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Synergetic nanotechnology for innovations and sustainable developments
นาโนเทคโนโลยี ร่วมสร้างสรรค์นวัตกรรมและการพัฒนาที่ยั่งยืน
The 5th Thailand International Nanotechnology Conference, organized by Nanotechnology Association of Thailand and Suranaree University of Technology, will be held during November 27-29, 2016 at Greenery Resort Khao Yai Hotel, Nakhon Ratchasima, Thailand. This bi-annual conference will focus on the integration of Engineering, Materials Science, and Nanotechnology to address fundamental nanotechnology opportunities and its applications.
The focus will be on the following areas:
• Nanomaterials & nanostructures
• Theory and simulation related to nanosystem
• Nano-energy & storage
• Environmental nanotechnology
• Nano-medicine & biotechnology
• Nano-agriculture
• Nano-characterization & instruments
• Nano-fabrication & manufacturing
• Nano-safety
• Nano-electronics/systems
• Other related topics
Plenary Speakers
|
Prof. Harald Krug, EMPA, Switzerland |
|
Prof. Y. Kawazoe, Tohoku University, Japan |
Prof. Erik Reimhult, U. of Natural Resources and Life Sciences, Austria |
Prof. Albert Schulte, Suranaree Univ. of Tech., Thailand |
Venue
http://www.greeneryresort.com/
GPS: 14.540114, 101.375251
map
Journals
After a peer-review process, all accepted papers will be published in the following journals.
- Advances in Natural Sciences: Nanoscience and Nanotechnology (IOP) (ISI with Impact Factor = 1.581)
- Materials Today: Proceedings (Elsevier) (Indexed in ISI and SCOPUS)
- Walailak Journal of Science and Technology (in SCOPUS)
- Chiang Mai University Journal of Natural Sciences (in SCOPUS)
- Suranaree Journal of Science and Technology (in EPSCO and TCI Tier 1)
Website
https://indico.cern.ch/e/NanoThailand2016
In order to reduce the size of magnetic head in hard disk manufacturing, an important assemble process required to further develop is an adhesive dispensing at controllable small amount in order of nanoliter. Together with the confined tiny space during assembly, the exposure of UV light for rapid adhesive curing may not be possible thus the shadow curing with shorten period is also needed to be developed. For manufacturing process, a method to determine the percentage of cure of this tiny adhesive dot is also necessary to verify the optimum assemble process. In this work, the rheology of adhesive was studied for two dispensing systems including time-pressure and microdot valve dispensing systems. The system parameters including air pressure, dispensing time and spring force were varied to determine the limitation of parameters relative to fluctuation of dot size variation. The material parameters of adhesive especially viscosity were also modified in order to describe the type of fluid flow behavior. After forming the desired dot size, the curing process was investigated by heat cure, UV cure and dual cure. The gel fraction and differential scanning calorimeter (DSC) were used to determine the curing percentage. The amount of heat required to complete phase transition indicated in DSC cure is the reliable parameter to determine the degree of cure. Fourier transform infrared absorption is hard to apply to detect the curing process while the Raman spectroscopy has advantage potential to determine the degree of curing. The micro-Raman spectrometer can demonstrate the micro-region of different degree of cure on nanoliter adhesive dot size by the ratio of observed peak heights.
Highly dispersed Ni and Cu nanoparticles on SBA-15 were successfully prepared by a modified impregnation route and evaluated in hydrogenation of methyl levulinate to γ-valerolactone (GVL). This catalyst was mainly characterized by such techniques as high resolution transmission electron microscopy, X-ray diffraction, N2 adsorption-desorption analysis, H2 temperature-programmed reduction. It was found that Ni and Cu nanoparticles were highly dispersed and anchored into the well-ordered mesoporous channels of SBA-15. As compared with conventional impregnated catalyst, the catalyst exhibits higher conversion of methyl levulinate and better yield of GVL at 200 oC in 3 h with 2-propanol as both solvent and H-donor. The superior catalytic performance can be attributed to the confinement effect deriving from the mesoporous channels of SBA-15, as well as the synergy of highly dispersed Ni and Cu nanoparticles.
Freshness of products is a key factor for food industry to monitor to ensure high quality products and retain customers’ satisfactory. Integrity package is capable of pointing out the quality of the products, based on the reaction between indicator and metabolites of spoilage microorganisms. In these regards, detection of volatile compounds such as ammonia gas is one of effective approaches in monitoring meat freshness. Functionalized nano-sensors, such as nanofibers with high surface areas and light weight, are attractive candidates for use in these applications by embedding in package headspace. This can lead to enhancement in detection efficiency of the devices. In this work, nanofibers of blends of biodegradable and biocompatible polylactide (PLLA) and hydrophilic polyglutamic acid (γ-PGA) are prepared by electrospinning. This leads to a combination of carboxylic acid functional groups on supporting PLLA matrix nanofibers. The nanofibers are prepared at 4 PLLA/γ-PGA ratios (100/0, 95/5, 85/15 and 75/25). To restrain the presence of γ-PGA, the blended fibers are cross-linked by employing reaction of their carboxylic acid and hydroxyl groups of glycerol (G) and ethylene glycol (EG). FTIR and SEM results suggest that the γ-PGA component is released from the original (untreated) PLLA/γ-PGA fibers when submerged in water, while those cured by EG and G can retain high amount of γ-PGA on the fibers. Comparing the efficiency of cross-linkers, EG exhibits high value of retaining γ-PGA due to its higher the reactivity. The ammonia absorption activity of the materials are examined. The results clearly depict that the fibers can absorb ammonia molecules by using the reaction of carboxylic acid groups on γ-PGA. The materials have high potential for use as test kits for monitoring meat freshness or in extending shelf life of the products.
F-doped ZnO nanorod were synthesized via hydrothermal process with variation of processing temperature and Fluorine doping contents (0-10%) starting from zinc oxide thin film as a seeding layer for nanorod growth. The zinc oxide seeding thin film was prepared by sol-gel spin coating at 2000 rpm on glass substrate using zinc acetate precursor with annealing at 500 °C in air for 2 h. Ammonium fluoride (NH4F) was used as F doping precursor. The properties of F-doped ZnO nanorods were characterized by field emission electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Four-point probe technique and UV-Visible spectrophotometer. Corresponding results indicated that growth of ZnO:F nanorod with good crystallinity and grown in (002) plane. The influence of F dopant incorporated into ZnO nanorods has been extensively investigated and discussed.
Magnesium ferrite ($MgFe_{2}O_{4}$) is one of the magnetic materials in spinel ferrite group which could be utilized for using in adsorbent applications due to their removability from medium solution by applying external magnetic field [1,2]. The capability of functionalization by grafting specific functional groups on their surfaces provide the possibility to synthesize the different types of magnetic nanoparticles for removing a large number of both organic and inorganic contaminants in wastewater [3]. Amongst many pollutants, heavy metal ions and dyes are considered as the crucial problems in wastewater. Thus, this present work focuses on using the synthesized magnesium ferrite nanoparticles as the effective heavy metal and dye nanoadsorbents. Mesoporous amine-functionalized $MgFe_{2}O_{4}$ nanoparticles ($MgFe_{2}O_{4}–NH_{2}$ NPs), with maximum magnetization of around 35 emu•g-1, were successfully synthesized and simultaneously functionalized under a refluxing condition by using ethanolamine as a surface modifier. The grafting of amine groups onto the $MgFe_{2}O_{4}$ NPs was clearly confirmed by the Fourier transform infrared spectrum. Adopting the $MgFe_{2}O_{4}–NH_{2}$ NPs as magnetic nanoadsorbents to remove heavy metal and dye from simulated wastewater is reported. Related to this aspect, the optimal adsorption conditions were carefully examined. It was found that the obtained materials exhibited excellent removal efficiency together with rapid adsorption [4].
References
[1] B. Y. Yu and S. Y. Kwak: Dalton Trans. 40, 9989 (2011).
[2] S. Mohapatra, S. R. Rout and A. B. Panda: Colloids Surf. A 384, 453 (2011).
[3] J. Gómez-Pastora, E. Bringas and I. Ortiz: Chem. Eng. J. 256, 187 (2014).
[4] J. Nonkumwong, S. Ananta and L. Srisombat: RSC Adv. 6, 47382 (2016).
In this work, Titanium dioxide (TiO2) mix phase powders with specific mixing ratio were prepared by sonochemical process in combination with calcination at different temperature in range of 400oC to 1000oC. The as-prepared powders were dispersed with tetraethyl orthosilicate (TEOS) as supported matrix of TiO2 for homogeneous colloid and used as starting precursor for thin film coating. The designated thin films were deposited onto glass substrates by dip coating process. X-ray diffraction technique was employed to evaluate TiO2 phase ratio meanwhile the film morphologies and hydrophilicity were investigated using scanning electron microscope and water contact angle, respectively. UV-Vis spectrophotometer was used to analyse the optical properties of the film. Photocatalytic activity of the prepared film was performed by mean of the decolorization of Rhodamine B dye solution under solar irradiation. The photocatalytic performance of assigned films were investigated and correlated mechanisms responsible for the activity are discussed.
To be added
It is well known that many physical properties of materials can be determined by the existence of point defects, which might be intentionally or accidentally added to the materials. For example, the electrical conductivity of Al-doped ZnO sample can be decreased by the presence of Zn vacancy (VZn) defect, which might be unintentionally created under O-rich growth conditions. In addition, the hydrogen defect is also reported to be a major obstacle for achieving p-type ZnO. Therefore, understanding the role of defects in materials can help us improving the material properties in a desired way. By combining the first-principles calculations with proper characterization techniques, such as x-ray absorption, infrared absorption, and photoluminescence, defects in materials can be understood in a great detail. A few examples, including Al-doped ZnO, SO-doped CdTe and N-doped Cu2O, will be presented.
Optical Coherence Tomography (OCT) is an optical imaging technology that produces cross-sectional image similar to that obtained by Ultrasound imaging but at much higher resolution, higher imaging speed, and higher sensitivity. Unlike other optical microscope, OCT utilizes low-coherence properties of the broadband light source to gate the sample’s microscopic structure over depth and hence is capable of noncontact and nondestructive three dimensional (3D) mapping of sample’s structure. Moreover, utilizing the principle of light interference in the frequency domain, our custom developed OCT systems is capable of imaging speed of more than 100 frames per second. This high speed imaging capability allows for three dimensional (3D) imaging in less than 10 seconds, which is useful for nondestructive monitoring of micro structures of samples in 3D and in real time. Here, we report the progress on the development of several techniques of nondestructive metrology using OCT system, such as surface topography, thickness topography, refractive index profilometry, 3D flow velocity mapping, 3D elasticity measurement, and polarization sensitive characterization. Furthermore, several approaches to push the limit of OCT for 3D characterization of nanomaterials will be presented and discussed.
Keywords: Optical tomography, 3D imaging, Thickness topography, Elastography, Birefringence map, flow analysis
A systematic investigation of CO_{2} electroreduction to CH_{3}OH on copper-based alloys stepped (211) surfaces was performed using density functional theory calculations associated with the standard hydrogen electrode model. The interaction of the key C_{x}H_{y}O_{z} intermediates is shown to be related to the CO adsorption energy due to the similar charge transfer characteristics of the C−O bond in CO and those intermediates. The overpotential, the limiting-potential elementary step, and selectivity to CH_{4}, CH_{3}OH, and HCOOH are determined. The competitive reaction of H_{2} evolution is also investigated. The results demonstrate that the CO protonation is the limiting-potential step on most surfaces, with the exception on Cu_{3}Au and Cu_{3}Co surfaces. Methanol production is favorable on Cu_{3}Pd and Cu_{3}Pt surfaces, yet they show high overpotential (∼0.7 V). In spite of the excessive strong CO interaction on some surfaces, the overpotential may be reduced on the surface which is able to decouple the CO adsorption energy and HCO/COH adsorption energy. The key of methanol selectivity is CH_{2}OH intermediate formation favorability associated with the preference of CH_{2}OH protonation at the C atom over the O atom. The calculations reveal that the electroreduction activity on Cu-based alloys catalysts do not show a volcano-type relation as was previously found on pure metal catalysts.
Melatonin (N–acetyl–5–methoxytryptamine) is a natural hormone produced by the pineal gland, located behind the third ventricle in the brain that it is used to control the human sleep cycle. Consequently, it has been widely used as a drug for the treatment of the sleep disorder. Melatonin encapsulated niosome particle is an important key for drug delivery application. It is well–known that the melatonin has hydrophilic and lipophilic properties which enable it to pass easily into any cell, fluid or compartment within the body. In this study we report the molecular structure and dynamical properties of the melatonin molecules in the bulk water and at the water-air interface. Molecular dynamics simulations were performed at the temperature of 298 K and the pressure of 1 bar was simulated until it reaches to equilibrium. Afterward the structural and dynamical properties of the melatonin which are randomly distributed in the bulk water and at the water–air interfaces were calculated and compared with the previous studies. In the case of the melatonin in the bulk water, the simulation indicates that the melatonin molecules favor to form aggregation by separated from the bulk water, which is quite obvious. This implies that the melatonin exhibits more solubility in lipid phase than the water phase. In the case of the melatonin randomly distributed on the water–air interface, the simulation reveals that the melatonin molecules favor to form the monolayer film at the interface. The melatonin tailgroups favor to adsorb on the water surface while their headgroups point to the air phase. For the two systems, the self–diffusion coefficient of the water was calculated, and finding it decreasing ~ 36.1 % from the pure water simulation. Such characteristics shows that the self–diffusion coefficient of the water is reduced due to obstruction effects in which are similarities to that reported for surfactant self–assembly formation in solvent. In addition, we also find that the probability for hydrogen bond formation between the melatonin–water molecules of the two systems are occurred as follows: Carbonyl Oxygen(acceptors)–HW(donors), Indole NH(donors)–OW(acceptors), Amide NH(donors)–OW(acceptors), and Methoxy Oxygen(acceptors)–HW(donors), respectively. While, the melatonin–melatonin molecules of the two systems are occurred as follows: Indole NH(donors)–Carbonyl Oxygen(acceptors), Amide NH(donors)–Carbonyl Oxygen(acceptors), Indole NH(donors)–Methoxy Oxygen(acceptors), and Amide NH(donors)–Methoxy Oxygen(acceptors), respectively. Fortunately, this model can be good reproduced the quantum chemistry calculation that reported previously for the hydrogen bond formation.
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Nanotechnology are beneficial for safe and efficient consumption of food, water and agricultural products. The NANOTEC-CU center of excellent on food and agriculture has focused the research in molecular design, synthesis and fabrication of nanomaterials for applications in the field of food and agriculture including chemical analysis and delivery systems. Various chromophores and fluorophores responsive to changes of physical environment and chemical contaminants are developed as the indicators for ensuring safety and quality of foods, drinking water and agricultural products. Molecular self-assemblies of amphiphilic molecules or large -conjugated arrays allow facile fabrications of nano-sized materials for simple and efficient applications of sensing, storing and delivery systems. Micellar incorporation of essential oil into edible natural polymers allows effective preservation and simple usage of Thai natural herbs in foods and drinks. Graphitic nanocarbon cluster are developed as an efficient delivery vehicle for biological active compounds and genetically important agents into cells and nucleus.
Keywords: Drug delivery, Food safety, Molecular self-assembly, Sensor, Vesicle
Nanocellulose is a cellulose-based material that possesses at least one of its dimensions in the nanometer range. Due to its unique characteristics, including its excellent mechanical properties, high degrees of thermal stability and water holding capacity, biodegradability and biocompatibility, nanocellulose is a promising naturally-derived material that can be used for various biomedical as well as agriculture and food applications. Typically, nanocellulose is produced from wood-based sources but interest in producing nanocellulose from fruit and vegetable by-products is on the rise as these residues are available in large quantity. The residues can also be more easily transformed into the desired material with less use of chemicals since the fibers of fruits and vegetables are more vulnerable than those of the woody plants. Increasing the yield of nanocellulose produced from such residues remains a challenge, however. Hydrothermal, chemical or enzymatic pretreatment methods may need to be applied to help disintegrate the inter-fibrillar hydrogen bonds of native cellulose microfibrils into nanosized fibrils to achieve such an objective. In this presentation, a brief review on how selected pretreatment methods can help enhance the defibrillation process will be mentioned. Use of nanocellulose in various food-based applications, including its use as a food additive or as a starting material for the production of edible packaging films will also be highlighted.
Elongating filaments systems, such as actin, are polymerizing motors that drive movement in many biological processes. The actin filament is astonishingly well conserved across a diverse set of eukaryotic species. It has essentially remained unchanged in the billion years that separate yeast, Arabidopsis and man. In contrast, bacterial actin-like proteins have diverged to the extreme, many of which are not readily identified from sequence-based homology searches.My laboratory is particularly interested in understanding how the force generated from these varied polymerization system is integrated into different biological processes. Once understood, then these machineries have potential for exploitation in nanodevices.Finally, I will describe the non-physiological, yet curious, case the kinase domain of PAK4, which spontaneously forms crystals inside mammalian cells. We are exploiting this phenomenon to create sensors within mammalian cells.
The feasibility of using lime residues after juice extraction as a raw material to produce nanocellulose was determined in this study. Different processing schemes were applied by varying the pretreatment and defibrillation methods and conditions. Autoclaving at 110-130 C was performed as a pretreatment to remove hemicellulose and pectin from the native fiber. The fiber images obtained from transmission electron microscopy (TEM) technique revealed that the multiple homogenizing steps could effectively disintegrate the pretreated fiber into nanometer scale. X-ray diffraction (XRD) results showed that the prepared nanocellulose possessed much higher crystallinity index (CI) comparing to that of the native fiber; it was noted that the degree of CI was dependent on the processing conditions. The results suggested that there is a potential to produce nanocellulose from citrus by-products via the application of the developed chemical-free technology, which is safely to be used for food applications.
Keywords: Lime residues; Nanocellulose; Hydrothermal
Caffeic acid phenethyl ester was successfully prepared by rapid expansion of supercritical solutions into liquid solvent. An average size of these CAPE nanoparticles was characterized by TEM and DLS techniques. They were found that diameters CAPE-NPs were ~40 to ~400 nm. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentration (MBCs) of CAPE nanoparticles were compared to CAPE particles using the plate count method against Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Vibrio parahaemolyticus. The antioxidant activities determined by the 2,2-diphenyl-1-picrylhydrazyl assay, ferric reducing antioxidant power assay and total phenolic content, respectively. MICs and MBCs of Gram-positive bacteria and Gram-negative bacteria were 350, 700 μg/mL and 1400 μg/mL. CAPE-NPs presented antioxidant activities similar to CAPE dissolved in 40 % ethanol but higher activities than that of CAPE in water. Antimicrobial and antioxidant properties of CAPE can be improved by a particle-size reduction in the ranges of nano-scale. In addition, the results should be generally applicable to nanoparticles fabrication to improve their bioavailability. As a powerful antimicrobial and antioxidant activities, CAPE nanoparticles could be a potentially promising application for active food packaging.
Keywords: Active packaging, Antimicrobial, Antioxidant, Caffeic acid phenethyl ester, Nanoparticles
We are experiencing an explosion in the amount of digital content that is being generated every minute and the need to store this content has seen the demand for data storage reach unprecedented levels. This has led to the emergence of the “Cloud” as the pre-eminent paradigm for data storage and represents a marked shift from how data used to be stored just a few years ago.
This talk focuses on advances in the field of nano-materials engineering and manufacturing in order to achieve increases in storage capacities in hard disc drives to meet the growing demand for Cloud storage. Nano-engineering of the write and read elements, head-to-medium spacing, and media grains are discussed in, both conventional Perpendicular Magnetic Recording (PMR), as well as Heat-Assisted Magnetic Recording (HAMR) applications and some of the manufacturing challenges and considerations.
Finally, projections for the growth of Areal Density from the current 1Tbits/in$^2$ to 5 Tbits/in$^2$ and beyond are discussed.
To be added
Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and synthesis). Printed Electronic also is a new wave of large-area electronics and flexible electronics manufactured by printing technology. The fusion of these two emerging technologies created the new opportunity to invent variety of novel electronic devices with low cost including nanosensors. Recent development on printed sensors based on graphene and graphene hybrid composite at TOPIC are comprehensively presented. Printed graphene based biosensors exhibited promising properties with good reliability suitable for commercial applications such as food pathogen sensors, biomedical sensors etc. Moreover, the application of printed graphene-based electronic devices researched at TOPIC will be presented including graphene-based electroluminescent light sheet, touch switch and supercapacitors for energy storage applications.
A simple electrosping system for fabrication of core-shell nanofibers
Chaturong Nettonglang1 and Santi Maensiri1,2,3
1School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
2SUT CoE on Advanced Functional Materials (SUT-AFM), Suranaree University of Technology, NakhonRatchasima, 30000, Thailand
3SUT-NANOTEC CoE on Advanced Functional Nanoaterials, Suranaree University of Technology, NakhonRatchasima, 30000, Thailand
Abstract
In this work, a simple electrospinning system for fabrication of core-shell nanofibers has been developed. The electrospinning set up as well as experimental procedure are described in detail. The fabrications of metal oxide and composite nanofibers with core-shell structures and other nanostructures are demonstrated. The prepared nanostructures are characterized by various techniques including thermal analysis, X-ray diffraction, Fourier transform infared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray absorption spectroscopy. This simple electrospinning syetm can be used to fabrication core-shell nanofiebrs for many innovative applications including ultrafiltration, fuel cells, membranes, tissue engineering, catalysis and drug delivery or release and nanofluidics and hydrogen storage.
This research was focused in two parts, experimental results and regression model. First, the research was studied on the proportion of cylindrical length that affected to the separation efficiency using a 40 mm hydrocyclone. The effects of cylindrical lengths of 60, 80 and 100 mm were investigated. The tested suspension was the mixed of silica and water. The silica particles have an average size of 9-10 micrometer at the solid concentration of 0.5% w/v. The feed flow rate of 1 m3/hr was operated with the flow ratio of 0.1. From experimental result, it was found that the shorter cylindrical length, the higher separation efficiency. At the condition of the cylindrical length of 60 mm, the vortex finder length of 40 mm and the conical length of 200 mm revealed the best separation efficiency up to 84.06 percent. Second, regression model of Euler number of hydrocyclone was presented. In this work, data obtained from the experiments in the first part and data of earlier researches totally of 75 were used to make the relationship between the proportion of hydrocyclone and Euler number. By the multiple linear regression method, it was found that the constants, was 3,439 and the regression coefficient of n2, n3, n4 and n5 were 0.380, 0.486, 0.222 and 0.039, respectively.
Keywords: Cylindrical length, Regression model, Euler number, Hydrocyclone
Carefully controlled core-shell nanoparticles can be used in biomedical applications, e.g., as biomedical imaging contrast agents, for hyperthermia and in drug delivery [1, 2], as well as for biotechnological applications such as separation and purification. Unique material functions can be achieved by using nanoscale inorganic cores, such as plasmonic or superparamagnetic interactions with electromagnetic fields. However, to enable these functions in a biological environment a dense organic shell has to control colloidal interactions with biomolecules, cells and other nanoparticles [1, 3]. Control over nanoparticle physical properties through an organic shell also allows tailoring of the assembly of functional nanoparticles into supramolecular structures, such as nanoscale vesicles or nanoscale Pickering-type emulsomes. The self-assembled structures can incorporate environmentally responsive building blocks and therefore be controlled through the strong interaction of the inorganic core with externally applied electromagnetic fields.
I will describe multiple recent developments from our lab regarding the synthesis and assembly of superparamagnetic core-shell nanoparticles that illustrate this design philosophy. The combination of new organic shell grafting methods [3-7] and control over nanoscale self-assembly [8-13] has allowed us to vastly improve performance of superparamagnetic core-shell nanoparticles, perform detailed investigations of interactions of colloidal responsive nanoparticles as well as demonstrate unprecedented control over magnetically controlled nanovesicular and nanoemulsion systems for transport and release applications that could impact future directions in drug delivery and biomedical imaging.
During the last decade several literature surveys on “Nanotoxicology” have shown that most of the published data on toxicological effects of nanoparticles or nanomaterials is not useful for risk analysis or risk assessment of these materials1, 2. Although the evaluated publications use buzz words such as “toxicological effects”, “risk assessment”, “toxicity” or “genotoxicity” most of them do not respect the rules of toxicological studies. As the term “nano” in the title was nearly a guarantee for project proposals to get money within the last two decades, no one claimed for the adequate quality control which should be applied for toxicological studies.
Most of the published studies contain severe weaknesses such as missing controls, no well characterized materials or they show high-dose-experiments only to observe an effect which is publishable3. Altogether this ends up in the situation that we cannot use all published data without its critical evaluation4.
The evaluation of nearly 6000 publications is in some respect disappointing. If one looks carefully into the details of the published studies it becomes more and more apparent that many of these publications contain shortcomings as mentioned above and often the conclusions drawn from these studies are misleading1. Hence, it would be a great mistake if regulation would be built upon such studies. Obviously, the above described limitations offer difficulties in issuing clear statements on “Safety Aspects of Nanomaterials”. International standards and harmonization of test protocols are urgently needed and should be used in all future projects and experiments.
Nanotoxicology or better nanosafety research may be pushed back on track if the researchers will respect measurement uncertainty and other important rules for biological studies in total and specifically for toxicological studies5,6. One recent example for a possible approach to achieve better quality for nanosafety studies is available online. Here a consortium build up from 6 international institutes in different countries from America, Asia and Europe carried out a study on the harmonization of a cytotoxicity assay for the measurement of nanomaterials in an interlaboratory round robin7. This pioneering activity is our showpiece project and may serve as a set point for future nanosafety research quality standards.
References
Metal-oxide semiconducting (MOS) Nanostructures prepared by microwave assisted thermal oxidation technique are demonstrated. With this simple and fast process, MOS nanostructures with various morphologies can be synthesized such as ZnO tetrapods, interlinked ZnO tetrapod networks (ITN-ZnO), MgO nanoparticles, CuO/Cu2O fibers. Mostly, ITN-ZnO morphology which have tetrapod-like features with leg-to-leg linking is presented here. The electrical and ethanol-sensing properties related to the morphology of ITN-ZnO compared with those of other ZnO morphologies are investigated. It is found that ITN-ZnO unexpectedly exhibits superior electrical and gas-sensing properties in terms of providing pathways for electron transport to the electrode. A UV sensor and a room-temperature gas sensor with improved performance are achieved. Therefore, ITN-ZnO is an attractive morphology of ZnO that is applicable for many new applications because of its novel properties. The novel properties of ITN-ZnO are beneficial for electronic, photonic, optoelectronic, and sensing applications. ITN-ZnO may provide a means to improve the devices based on ITN-ZnO. Moreover, MgO nanoparticles and CuO/Cu2O fibers prepared by microwave assisted thermal oxidation technique are also demonstrated and applied for dye-sensitized solar cells.
Novel biodegradable nanocomposite blown films based on compatibilized poly(lactic acid)-poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends were fabricated for use as packaging for dried longan. Silver-loaded kaolinite (AgKT) dispersed in the polymer matrix as intercalated-exfoliated microdomains improved the properties of the films, in particular the moisture barrier properties. In addition, controlled silver release provided long-term antibacterial activity which can be attributed to AgKT's layered structure. The amount of released silver ions also complies with migration levels specified by the standard for food-contact plastic packaging. It was found that as little as 4 phr AgKT in the nanocomposites decreased the film’s elongation at break from 213.0±5.85% to 53.8±1.81%, increased thermal stability for processing, and decreased the water vapor permeability by 41.85%. The shelf-life of dried longan as predicted experimentally by a moisture sorption isotherm and theoretically by the Peleg model were almost identical (∼308 days) and were more than twice as long as for the films without AgKT under ambient conditions. Biodegradability testing for the whole life cycle was also carried out for the PLA/PBAT films both with and without AgKT and compared with PLA alone. The PLA film showed the highest rate of biodegradation followed by the PLA/PBAT blend and the PLA/PBAT/AgKT nanocomposite, respectively. Even though the presence of AgKT in the nanocomposite slowed down its rate of biodegradation, its % biodegradation of 69.94 % at the end of the test period (90 days) still conformed to the Chinese National Standard (GB/T 20197-2006) for a biodegradable plastic by being higher than 60 %. On the basis of these properties, the PLA/PBAT/AgKT nanocomposites are considered to be promising candidates for use in film packaging applications to replace non-biodegradable and petro-based plastics
Carbon nanofibers composite with manganese or copper manganese ferrite (CNF/MFe2O4: M = Mn, CuMn) have been successfully fabricated by a combination of electrospinning and heat treatment process. The structure and morphology of prepared samples were characterized by means of TGA, XRD, SEM, BET, XAS and XPS. The potential application of the prepared samples as an electrode material for supercapacitor was studied using CV, GCD and EIS techniques. The specific capacitance of about 122, 219, and 344 F/g were observed for CNF/MnFe2O4 carbonizaed at 500, 600 and 700 oC, respectively. The improvement is due to increasing of surface area with increased carbonization temperature. In this work, the ACNF/CuxMn1-xFe2O4 (x=0.2, 0.4, 0.6, and 0.8) were also prepared due to the activated carbon and cupper doping in manganese ferrite are two of the effective approaches to enhance the energy storage in supercapacitors. It was found from the result that, Cu content has a significant effect on the electrochemical performance of ACNF/CuxMn1-xFe2O4 electrodes. ACNF/Cu0.2Mn0.8Fe2O4 shows the best specific capacitance of 384 F/g compared to the other three samples. This might be largely attributed to the phase transition and anti-sites defects of spinel crystal cell resulting from the Cu substitution for Mn. By comparing the capacity of CNF/MnFe2O4 and ACNF/CuMnFe2O4 carbonized at 600 oC, the ACNF/CuMnFe2O electrode exhibited a maximum specific capacitance of 384 F/g, where as non-activated CNF/MnFe2O4 showed the specific capacitance of about 220 F/g .The superior electrochemical performance of ACNF/CuMnFe2O may due to large surface area from activation process and high conductivity from cupper doping. Moreover, the combination of the pseudocapacitance behavior of MFe2O4 (M = Mn, CuMn) and the electric double layer capacitance of CNF (or ACNF) well supported the enhancement of specific capacitance.
In this work we report the dc bias effect on dielectric properties and nonlinear current-voltage behaviors of Bi1-xBaxFeO3 (where x = 0, 0.05, 0.1, 0.2, and 0.3) ceramics synthesized by a co-precipitate process. Structural studies using X-ray diffraction (XRD) show the formation of small amount of second phase (Bi2Fe4O9). Ba-doped samples show the Rhombohedral (R3c) and Orthorhombic (Pbam) distorted structure mixed phase. SEM images indicate the average grain size decreases with the increase of Ba content and the average grain size of Ba-doped samples is about 6.48-3.28 . The dielectric constant and loss tangent of the Ba-doped pellets were measured between 100 Hz – 1 MHz under an applied dc bias voltage. Interestingly, it is observed that the dielectric constant gradually increases with increasing dc bias voltage for all of Ba-doped samples at low frequency region (<104 Hz). The grain boundary activation energy has been investigated using impedance microscopy. The leakage current density behavior is significantly enhanced with increase of Ba doping concentration. The relationship between J-E reveal that all of samples exhibits nonlinear characteristic, which is similar to that reported in Ba-doped CCTO ceramics [1]. The non-Ohmic property is described by the existence of Schottky-type barrier in the samples.
Keywords: Bismuth ferrite; Dielectric property; Nonlinear behavior; Impedance analysis
[1]. P. Thongbai,S. Vangchangyia,E. Swatsitang,V. Amornkitbamrung,T. Yamwong, & S. Maensiri. 2013. Non-Ohmic and dielectric properties of Ba-doped CaCu3Ti4O12 ceramics. Journal of Materials Science: Materials in Electronics, 24, 875-883.
Ce1-xFexO2 nanofibers (NFs) and nanoparticles (NPs) (x=0, 0.08 and 0.10) were prepared by electrospinning and the simple solution process, respectively. Each of sample was calcined at 500, 600, 700, and 800 ˚C. The calcined samples were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Spectroscopy (XAS) and Vibrating Sample Magnetometer (VSM). Both of XRD and TEM with Selected Electron Diffraction (SEAD) analysis indicated that the Ce1-xFexO2 nanostructures have a cubic structure without any secondary phase. TEM was shown nanofibers of ~30-60 nm while SEM was shown nanoparticles of ~9-40 nm. The as-spun samples were exhibited a diamagnetic behavior, whereas the calcined of Ce0.90Fe0.10O2 nanofibers samples exhibited ferromagnetic behavior with the specific magnetizations of 0.04 – 0.32 emu/g at 10 kOe. XAS spectra was showed the valent state of mixed Fe3+ and Fe2+ in the Ce1-xFexO2 samples indicating oxygen vacancies in the nanostructures. Similarly, XPS spectra confirmed that there are oxygen vacancies in the nanostructures. These oxygen vacancies play an important role to induce room temperature ferromagnetism (RT-FM) in the calcined of Ce1-xFexO2 nanostructures. Our results indicated that the ferromagnetic properties of Ce1-xFexO2 system is intrinsic and is not a result of any secondary magnetic phase or cluster formation.
Two 8-aminoquinoline derivatives, Q1 and Q2, containing one and two quinoline groups, respectively, are synthesized. In water, Q1 and Q2 showed strong electronic absorption peaks at 340 nm and 350 nm, with molar extinction coefficients of 3605 and 2475 M-1cm-1, respectively. The solutions are weakly fluorescent having quantum efficiency below 10%. In the presence of metal ions, the strong fluorescence signal at 480 nm is observed exclusively with Cd(II) ion. The fluorescence enhancement was probably the result of the restriction of photo-induced electron transfer (PET) process. In aqueous Tris solution pH 7.4, Q2 shows significantly greater fluorescence enhancement ratio (I/I0) of 30-fold comparing with 7-fold observed for Q1. The fluorescence detection of Cd(II) ion in water is possible in a wide pH range of 4 to 9 with the detection limit as low as 25 nM.
Interface and surface become important playgrounds for unconventional superconductivity, since they bring broken symmetry, competing orders, charge transfer, strain and other factors into the problem. Recently, interfacial superconductivity up to 75K has been discovered in FeSe/STO and FeSe/BTO interfaces [1,2]. In this talk, I will demonstrate that the combination of angle resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM) and molecular beam epitaxy (MBE) is a powerful tool to study the superconductivity at interfaces and surfaces. Specifically, I will present: our recent efforts in the understanding of the pairing symmetry of FeSe/STO [3] and the anomalous phase diagram of FeSe films upon surface electron doping [4,5]. Our results suggest that the interfacial effects, particularly interfacial electron-phonon interactions, may play a critical role in the high-Tc of FeSe/STO. In line with it, I will introduce our latest findings of the surprising interfacial structure of FeSe/STO.
[1] S. Tan et al., Nature Materials 12, 634 (2013).
[2] R. Peng et al., Nature Comm. 5, 5044 (2014).
[3] Q. Fan et al., Nature Physics 11, 946–952 (2015).
[4] C.-H.-P. Wen et al., Nature Comm. 7, 10840 (2016).
[5] W. H. Zhang et al., Nano Lett. 16 (3), 1969–1973 (2016).
Novel phenomena such as indirect to direct band gap transition, giant exciton binding energy, spin-valley-layer locking and polarization dependent valley control are attractive features of transition metal dichalcogenides (TMDs). Especially, the layer dependent indirect to direct band gap transition raised enormous interest in TMDs. There have already been many efforts to control the band gap with means other than the number of layers. Here, we report the possibility for electric field induced indirect to direct band gap transition in bulk MoSe$_2$ observed by using angle resolved photoemission spectroscopy (ARPES). In order to demonstrate the evolution of the electronic structure as a function of surface electron doping and/or surface electric field, we us in-situ alkali metal dosing on the surface of in situ cleaved MoSe$_2$. We find that the alkali metal evaporation affects the and the K point electronic structure differently. The difference in binding energy between valence band maximum (VBM) at the and the K points changes from 370 meV to 30 meV. Our results not only clearly show a possibility of indirect to direct band gap transition by electric field, but also show the relation between the gap size and surface electric field in this material.
Hydrogen is a promising candidate for the clean energy carrier that may replace fossil fuels. For the production of hydrogen, water splitting with efficient catalysts has been intensively studied over the past decades. Platinum, which is known to be the best catalyst for water splitting, is too expensive to be used in large-scale applications. Therefore, numerous earth-abundant materials have been investigated as a replacement of Pt. Recently, transition metal dicalcogenides (TMDs), most notably MoS2, are receiving a great deal of attention as a novel catalyst for water splitting. Although the basal plane of TMDs are efficient as catalysts, it was found recently that the sulfur vacancy in MoS2 can increase the catalytic activity for hydrogen evolution.
In this presentation, motivated by the previous work, we explore the detailed mechanism for hydrogen production from the sulfur vacancy in MoS2 and calculate the activation energies along the reaction path. Furthermore, we evaluate the catalytic efficiency of vacancy sites in various TMDs and suggest TMDs that may show high catalytic effects in hydrogen evolution reaction.
Alkali metal intercalation in layered-transition metal dichalcogenides (LTMDs) has been intensively studied due to a wide range of attractive properties such as enhancement of superconductivity, quasi-freestanding, and negative electron compressibility which lead to many potential nanoelectronic applications. Essentially, many researchers study the correlation between electron doping and strain (and vice versa) in order to manipulate their electronic structure, band gap, and carrier mobility. In this work, we have measured the electronic structure of 1T-HfSe$_2$ by using angle resolved photoemission spectroscopy (ARPES) together with $in~situ$ alkali metal evaporation. Our ARPES data as a function of electron doping show the monotonic increase of in-plane p-orbital valence band splitting (VBS) reaching as high as 350 meV and the band gap reduction up to 250 meV for a carrier density around 5x10$^{14}$ cm$^{-2}$ (corresponding to ~20% of Brillouin zone). These VBS values are very similar over various alkali metal dopants (including Na, Cs, and Rb) suggesting that the in-plane lattice reduction is dominated while the out-of-plane lattice expansion is neglected at the valence band maximum. The density functional theory calculation (DFT) has been used to understand the electronic structure of HfSe$_2$ under the condition of alkali metal intercalation and strain. At 25% of Na doping, the out-of-plane lattice constant (c) increases up to 11% while the in-plane lattice constant (a) decreases around 3% which can be described by the different coulomb interaction over Se atoms. The calculation of electronic structure under uniaxial tensile strain is very well in agreement of our ARPES data in both of VBS and band gap shrinkage indicating that uniaxial strain can be induced by alkali metal intercalation. Finally, our finding should help to simplify the study in strain physics as well as for large-scale strain engineered devices.
Keyword: alkali metal intercalation, layered-transition metal dichalcogenides, strain, angle resolved photoemission spectroscopy, density functional theory.
A two-dimensional electron gas (2DEG) (confined electron which is free to move in two dimensions at the interface/surface) was discovered at the LaAlO$_3$/SrTiO$_3$ interface; later on 2DEG was also observed at the bare surfaces of SrTiO$_3$ and KTaO$_3$. This system can enhance some physical properties (i.e. superconductivity and ferroelectric polarization) as well as the novel properties such as negative electron compressibility and unusual coexistence of ferromagnetism and superconductivity. In this work, by using angle-resolved photoemission spectroscopy, we have studied the temperature dependence (T=20-130K) of 2DEGs at bare surfaces of ferroelectric KNb$_x$Ta$_($$_1$$_-$$_x$$_)$O$_3$ (KTN) (x=0.02, 0.03 and 0.05) across their ferroelectric transition temperatures (T$_c$). We found that the 2DEG spectral weight gradually decreased at temperature below ferroelectric T$_c$. The possible reason can be described by the transition from paraelectric to the ferroelectric which broadens the quantum well state due to electrical polarization. The number of electrons, which are initially confined at the surfaces, will be delocalized and hence the electronic spectral weight of 2DEG nature is changed. Our finding may help mediate the fundamental study of 2DEGs and phase transition as well as for functional oxide devices.
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Cancer is the leading cause of death in Thailand. Despite advances in cancer research during the past decades, the survival of cancer patients has only marginally improved and the cure remains unlikely. Complex genomic heterogeneity and limited drug delivery represent major obstacles for effective antineoplastic treatments. Thus, new therapeutic strategies to increase drug delivery may improve outcome for cancer patients. Among several approaches, nanoparticle conjugate is a promising modality with distinct characteristics that are favorable for cancer drug delivery. Nanoparticles can be developed not only to improve drug delivery, but also to offer diagnostic and monitoring capabilities. This emerging molecular platform is called “theranostics”. Theranostic nanoparticles include liposomes, micelles, dendrimers, nanospheres and others. These particles can protect drugs and deliver them to targets in a controlled manner. In addition, they can be decorated with “molecular antennae” such as antibodies or aptamers on their surface to allow specific interaction with targets of interest. During this presentation, current collaborative research efforts between NANOTEC and Faculty of Medicine Siriraj Hospital, Mahidol University exploiting nanoparticles to target brain, liver, colorectal, breast and gynecologic cancers will be discussed.
Poor oral absorption and rapid enzymatic degradation are the major hurdles in to deliver peptide drugs orally and vaccines via the mucosa. We developed stable, orally available peptide drugs through the chemical addition of specifically designed lipids and carbohydrates, creating amphiphilic compounds capable to reassemble to form nanoparticles.Fertility is controlled by decreasing the level of circulating Gonadotropin-Releasing Hormone (GnRHor stimulating the down-regulation of GnRH receptors on gonadotrope cells. Using two independent approaches we regulated the action of GnRH on gonadotropic cells, thereby controlling fertility inmice and ram models.
We have also developedan oral vaccine delivery system to prevent infection byGroppA streptococcus (GAS) by encapsulating lipid core peptide (LCP) antigens into the liposomes.We synthesised the LCP constructby attachingC-16 lipoamino acid (Toll-like receptor 2 agonist)toJ-14 (B-cell epitope derived from GAS M-protein)andP25 (CD4+ T helper cell epitope).Blank liposomes were formulated and optimized for charge and lipid content using a thin film formation method.Optimized liposomes were coated with oppositely chargedpolyelectrolytes(positively chargedtrimethyl chitosan (TMC) and negatively charged sodium alginate)in a layer-by-layer approach. These formulations were subsequently characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Spherical-shaped liposomes surrounded by films of TMC and sodium alginate were observed by TEM. DLS analysis of coated liposomes showedmonodispersed particles with a polydispersity index of 0.24,hydrodynamic diameter230 nm andzeta potentialof -40mV. Optimized formulationswill be further investigated for theirefficiency of uptake by intestinal immune cells and ability to induce mucosal IgA and systemic IgG responses.
Nanotechnology and Health
Teerapol Srichana
NANOTEC-PSU Excellence Centre on Drug Delivery System, Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat-Yai, Songkla 90112, Thailand
Email address: teerapol.s@psu.ac.th
Nanomedicine and nanotechnology provides an early detection and prevention of diseases resulting in improved diagnosis, proper follow-up and treatment. Nowaday biological testings can be performed quickly and become more sensitive and reliable. Potential impact of nanoscience on healthy care is summarized and given in in this presentation. Electronic networks with semiconductors interface nerve cells can be applied in brain research and neurocomputation. Quantum dots (nanometer-sized crystals) contain free electrons and emit photons when submitted to UV light have been introduced into early tumor detection and could locate as few as 10 to 100 cancer cells.
Nanoparticles are used for site specific drug delivery. This technique required drug dose is lowered therefore side-effects are lowered significantly as the active agent is deposited in that region only. This highly selective approach can reduce costs and pain to the patients. Various nanoparticles such as liposomes, liquid crystals, micelles find an application. Liquid crystal and micelles synthesized in house are used for drug encapsulation. Nanodelivery system together with drug targeting to the organ can deliver drug molecules to the desired location. A targeted medicine reduces the drug dose and side effects.
Nanomedicines may improve drug bioavailability both at specific places in the body and over a specified period of time. The molecules are targeted and delivered to precised cells.
Unique nanostructures were designed for controllable regulation of proliferation and differentiation of stem cells by designing unique nanostructures. This will lead to stem cell-based therapeutics for the prevention, diagnosis and treatment of human diseases. Nanofibers help heart muscle grow in the lab. Viruses are prevented to infect human by nanocoatings over proteins on viruses that could stop viruses from binding to cells. Nanorobots of nanosized delivery systems could break apart kidney stones, clear plaque from blood vessels, carry drugs to tumor cells. In the new era of personalized medicine we can have in vitro diagnostics, in vivo diagnostics, nanotherapeutics and theranostics.
Current and future health care challenges are in the area of infectious diseases, cancer, genetic disorders, aging, obesity and addiction. Gene Therapy may be a solution in several diseases by employing electrostatic gene condensation, efficient cellular entry, non-toxicity and high gene expression/silencing.
Bioimaging has been employed together with new technology in confocal laser scanning microscope, quantum dots, fluorescence microscope. Advanced flow cytometry is capable to detect cells, infected cells and cell endocytosis and even the antibacterial activities from live and death cells.
Thus nanoparticles are promising tools for drug delivery advancement, as diagnostic sensors and bioimaging. The biodistribution of nanoparticles is still under investigated due to the difficulty in targeting specific organs. Efforts are made to optimize and understand the potential and limitations of nanoparticulate systems. It is expected that the benefits will be gained from nanotechnology including lower drug toxicity, improved bioavailability, reduced cost of treatment and extended economic life of proprietary drugs.
Some examples of drug delivery systems are examples of research work in the NANOTEC-PSU on amphotericin B and rifampicin in liquid crystals systems were demonstrated the successful stories of nanotechnology. We can use the liquid crystal as nanocubic and nanovesicle to encapsulate the drugs into the system to give more effectiveness with less toxicity to the cells
Key words: drug delivery stem, cells, bioimaging
Highly sensitive detection is a major goal for sensing and/or diagnosis of diseases, food-borne bacteria and biological warfare agents. High specific and sensitive detections can be achieved via labeling techniques in DNA hybridization and antibody-antigen interaction. Labels based on nanoscale materials open a new opportunity over the traditional methods - in terms of greater reporting signal per binding event. We have been able to lower the limit of detection (LOD) of < 1 fM for DNA and < 1 fg mL-1 for antigens or < 5 CFU mL-1, without using PCR or other methods of non-electrochemical amplification. In addition, some possibilities on high-throughput simultaneous assays have been attempted and reported. The talk will describe some our approaches engineered electrochemical labels using nanomaterials such as carbon nanotubes, graphene, and metal nanoparticles. Last, the talk will also present some real food pathogen applications.
Abstract
By the use of nanotechnology in the development of bioassay kit, the ideal goals that inevitable are rapid, convenience and cost effective. Through our knowledge toward Human Immunodeficiency Virus-1/Acquire Immunodeficiency Disease (HIV-1/AIDS), we successfully produced a novel test kit for investigating both of HIV protease activity and HIV-1 protease inhibitors (PIs). This assay was developed using an immunochromatographic (IC) assay combined with colloidal gold tracers to establish the enzymatic activity IC strip test which can interpret result with the naked eye. In this present study we evaluated the efficacy of strip test by comparing the result of the strip test with the quantity of level of PI in HIV-infected patients detected by the High Performance Liquid Chromatography (HPLC) method. Various parameters including relative accuracy, relative sensitivity, relative specificity, and Kappa co-efficiency (k) of test kit were analyzed. The results revealed that the relative accuracy, relative sensitivity and relative specificity of IC strip were 97.8, 100%, and 96.8 % respectively. The Kappa co-efficiency (k) value was 0.95 showing the high strength of agreement of PI strip with the gold standard, HPLC method (p < 0.05). Suggesting that IC strip test has suitable efficacy to determine the PI in plasma samples from human immunodeficiency virus-infected patients.
Keywords: HIV-1 protease, HIV-1 protease, Immunochromatographic strip test, gold
nanoparticle
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Thailand is currently in the stage of moving forward in the area of humane science by reduce, refine and replacement of animals, knowing as the 3Rs principle, in research and development of consumer products. With this regard, the Thai Food and Drug Administration (FDA), Ministry of Public Health, has adopted ASEAN cosmetic directive for non-animal testing of cosmetics. Meanwhile, the use of conventional animals for toxicity testing is becoming obsolete as alternative methods are increasingly developed and validated for chemicals, which are also useful for the field of nanotoxicology. This talk will give an overview of nanosafety research at NANOTEC using in vitro models of cells, tissues, as well as microorganisms for investigating effects of nanomaterials to human health and the environment. In addition, zebrafish embryo is now increasing of interest as an alternative, since they are not considered as animal experimentation according to the EU Directive 2010/63/EU on the protection of animals used for scientific purposes. This model allows for study on embryonic development and various biomolecular endpoints.
With the increase of nano-consumer using nanomaterials, the potential exposure to nanomaterials have been raised. Therefore recently the human and environmental impacts of nanomaterials have emerged as an issue. However, there are no suitable methods to evaluate the cytotoxicity of nanoparticles based on high-throughput screening method. High-throughput approaches allow the bulk of the screening analysis for manufactured nanoparticles and high volume data generation for nanoparticle toxicity. To assess the potential toxicity of manufactured or engineered nanoparticles, traditional in vitro toxicity studies have been performed using normal 2D culture system. But several problems were encountered during assay validation, ranging from particle agglomeration in biological media and optical interference with assay system. To date, there are several ISO activities on the cytotoxic effects of nanoparticle using cell viability assay and detection of ROS level. This work item is different from the others in that new assay platform such as 3D cells on pillar insert was applied to evaluate the cytotoxicity to exclude the artifacts of traditional cell-based assay such as optical absorption and reactivity with assay reagent. 3D cells based on pillar insert provide more in vivo mimicking state and to allow us to easily change cell growth media or expose 3D cells to detecting reagents by immersing the tip of the pillar insert in different reaction plates. This method allows the high-throughput screening of nanoparticle cytotoxicity by excluding the optical absorption and reactivity with assay reagent.
Nano information is crucial for nano safety along the life cycle of nanomaterials. Transparency on nano content offers advantages for producers, downstream users and consumers of nanoparticles. There are differences is the nano perception between different continents. Consumers in Asian countries like to buy nano products with nano particles because they appreciate the advantages of nano particles in them. In Asia many products are advertised as nano products, even if they are imitations. Thailand has introduced a certification system Nano Q which helps to distinguish between real and fake nano products.
In European countries industry often fears harm through stigmatisation, if companies have to declare nano particles in consumer goods. Many of them prefer not to label their products even if they contain nano particles. Therefore classification and labelling has only been introduced in a few regions and in a few product categories, such as in cosmetics and in biocides. The justification for such regulation is the protection of human health and the environment from hazards and risks of nanomaterials and / or the consumers’ right to know if they buy products containing nano materials. There is an ongoing debate whether nano regulation including the compulsory declaration of nano particles in products is compatible with WTO law. The present article investigates nano regulations in various regions and their compliance with WTO rules.
Nanomaterials is well-known for their versatile applications in electronics, medicals, chemicals, catalysts as well as environments. By tuning their size, shape, morphology, and composition, one could systematically change their chemical, physical, electrical, mechanical, and catalytic properties. In this contribution, we chemically synthesized complex gold and silver nanostructure (nanospheres, nanoplates, nanoporous, and nanostars) using hydrogen peroxide (HP) as the reducing and shape-controlling agents. The strong etchant of HP and surface passivation of chloride ion promote the dissolution of certain facets while preserving and promoting growth of other facets enables the formation of complex nanostructures. By systematically tuned the nucleation and growth environment, we could selectively fabricate desired nanostructure. We then later explore their nano-size effects and surface enhance capabilities for trace chemical analysis using surface enhanced Raman scattering (SERS), tip enhanced Raman scattering (TERS) as well as light harvesting potential using organic solar cell (OSC).
Keywords: nanostructures, SERS, TERS, selective etching, hydrogen peroxide
References:
1. S. Vantasin, W. Ji, Y. Tanaka, Y. Kitahama, M. Wang, K. Wongrawee, H. Gatemala, S. Ekgasit, and Y. Ozaki, Angewandte Chemie International Edition 2016, 55, 8391 –8395.
2. P. Pienpinijtham, S. Vantasin, Y. Kitahama, S. Ekgasit and Y. Ozaki, J. Phys.Chem. C 2016, 120, 14663-14668.
3. H. Gatemala, C. Thammacharoen, S. Ekgasit and P. Pienpinijtham, CrystEngCom. 2016, 18, 6664-6672.
4. H. Gatemala, P. Pienpinijtham, C. Thammacharoen, S. Ekgasit, CrystEngComm, 2015, 17, 5530-5537.
5. P. Parnklang, C. Lertvachirapaiboon, P. Pienpinijtham, K. Wongravee, C. Thammacharoen, S. Ekgasit, RSC Advances 2013, 3, 12886–12894.
6. P. Parnklang, B. Lamlua, H. Gatemala, C. Thammacharoen, S. Kuimalee, B. Lohwongwatana, S. Ekgasit, Materials Chemistry and Physics 2015, 153, 127-134.
We reported the effect of boron addition on magnetic properties and structure of CoPt nanoparticles. The CoPt-B nanoparticles were synthesized by means of the polyol process. The magnetic property measurement showed that the CoPt-B sample exhibited a much larger coercivity compared to the sample without B additive at the same annealing temperature. Transmission electron microscopy and energy dispersive X-ray spectroscopy revealed that the average particle size was about 2 nm for the as-synthesized sample with the ratio of Co and Pt was close to 1:1. After annealing, the particle sizes increased but the composition was maintained. The phase transformation of the nanoparticles versus temperature was investigated using a combination of X-ray diffraction and in-situ X-ray absorption analysis. It was shown that the phase transition temperature at which the nanoparticles change from the disordered A1 phase to the ordered L10 phase occurs at temperature of 600 C. We concluded that boron additives could reduce the ordering temperature of CoPt of about 100 C.
The addition of B at up to 60% promoted the formation of the L10 phase when the nanoparticles were subjected to annealing at 600 C. If the B content is higher than 60%, the phase transition is suppressed. The evidence of B addition on the structure of CoPt nanoparticles was further supported by the magnetic measurements. The results show that the coercivity of the annealed CoPt-B nanoparticles was enhanced by the B additions from 20 to 60%, with the maximum coercivity of 12,000 Oe for the CoPt-40%B sample.
Keywords: CoPt, nanoparticles, magnetic properties, boron addition, phase transformation, recording media
The titanate nanotubes (TNTs) were synthesized by hydrothermal method and were composited with silver oxide nanoparticles (AgO) in various 1, 5, 10 wt.%. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray microscopy (EDX), and ultraviolet-visible spectroscopy (UV-vis). The phases of TNTs and TNTs-Ag nanocomposites were confirmed by XRD and EDX results. The dielectric properties of TNTs-AgO were studied at different temperatures (-50 °C to 100 °C) in the wide ranges of frequency (100 Hz to 1 MHz). The TNTs-AgO exhibited dielectric constant in the range of $10-10^4$ at frequency 1 kHz and 30 °C. Moreover, the dielectric constants of TNTS significantly decrease with increasing Ag composition due to the increase in the conductivity in the sample causing the reduction of the dielectric properties of TNTs.
In this study, we report the magnetic properties of BiFe1-xCoxO3 nanoparticles (with x = 0.05, 0.1, 0.2, 0.3) synthesized by a simple solution method. The prepared samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray absorption spectroscopy (XAS). The crytallize size calculated by using the Debye–Scherer equation decreases with increasing Co doping content. The magnetic properties of the nanoparticles were measured by a vibrating sample magnetometer (VSM). The M-H loops of all BiFe1-xCoxO3 nanoparticles exhibited ferromagnetic behavior at room temperature. The saturation magnetization (Ms) increased to be from 1.08 emu/g for BiFe0.95Co0.05O3 to 8.26 emu/g for BiFe0.7Co0.3O3. Co-doped BiFeO3 nanoparticles with smaller crystallite size also caused to the enhancement of the coercivity (Hc) and squareness (Mr/ Ms). The effect of Co doping on the structure and magnetic properties of BiFeO3 nanoparticles is discussed.
Ce1-xMnxO2 (x = 0.05, 0.075 and 0.1) nanoparticles were synthesized by simple solution method using cerium(III) nitrate hexahydrate manganese (II) nitrate hydrate (Mn(NO3)2∙H2O) and freshly extract egg white (ovalbumin) in an aqueous medium. The precursors were calcined at 600 °C for 2 h in air. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray absorption near edge structure (XANES) techniques. The XRD results indicated the presence of a cubic structure of Ce1-xMnxO2 in all samples. The SEM and TEM images showed thin platelike clusters with the particle sizes 20-40 nm. The oxidation states of Mn and Ce K-edge in samples were confirmed by X-ray absorption near edge structure (XANES) technique. The magnetic properties were studied by a vibrating sample magnetometer (VSM). All samples exhibit superparamagnetism behavior. The saturation magnetization (MS) of Ce1-xMnxO2 (x = 0.05, 0.075 and 0.1) nanoparticles increase from 0.00003 to 0.00035 emu/g with increasing Mn content. The origin of the magnetic properties observed in the prepared Ce1-xMnxO2 nanoparticles is discussed.
Abstract
Photocatalytic activity of Zinc stannate (Zn2SnO4) ZTO described in our previous work [1, 2] depict that ZTO nanoparticles have comparable photocatalytic activity to other photocatalyst such as Zinc Oxide (ZnO) nanoparticles and Titanium dioxide (TiO2) nanoparticles. The aim of this work is to explore the effect of annealing i.e. high temperature behavior on size, morphology and photocatalytic activity of room temperature synthesized nanoparticles.
It has been reported that annealing at high temperature results in alterations in surface states of semiconductor [3, 4]. These surface alterations can impact the dye adsorption on surface of catalyst. Room temperature synthesized samples were annealed to study the annealing effect at different temperatures on the photocatalytic efficiency of ZTO. Annealing was carried out at two different temperatures i.e. at 250oC and 400oC.
Scanning electron micrograph (SEM) of annealed particles was carried out in order to observe morphological changes before and after annealing at two different temperatures. SEM micrographs obtained for above samples revealed that annealed samples did not result in any morphological changes in the length or diameter of ZTO nanoparticles.
Optical absorption spectra of Methylene Blue (MB) adsorption on surface of ZTO nanoparticles annealed at 250oC and 400oC for period of one hour was calculated which perceived that the amount of MB adsorbed is higher for the ZTO samples without annealing as compared to samples annealed at different temperatures i.e. at 250 °C and at 400 °C.
UV/Vis optical absorption spectra of annealed ZTO samples was used to study the effect of annealing on native defects. It was observed that the absorption peak is at about 270 nm in all the cases i.e. annealed and without annealed samples which illustrate that the ZTO nanoparticles preserve uniform size after annealing at different temperatures.
Photocatalytic activity of annealed samples and without annealing was observed for the degradation of methylene blue and corresponding reaction rate constant k values were calculated.
From reaction rate constant k values it is evident that annealing didn’t result in improvement of photocatalytic activity as samples without annealing showed higher photocatalytic activity then sample annealed at 400oC.
This can be attributed to removal of surface defects due to annealing and subsequent reduction in photocatalytic activity.
References:
A new palladium nanoparticles catalyst supported on individual calcium carbonate plates (Pd/ICCP) is prepared from Asian green mussel shells and used as heterogeneous catalyst in Suzuki cross coupling reaction. The reduction of palladium (II) generates palladium (0) nanoparticles which can embed on individual calcium carbonate plates (ICCP) to give Pd/ICCP. The prepared Pd/ICCP catalyst is characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), indicating an entire dispersion of palladium onto the surface of individual calcium carbonate plates. Furthermore, palladium content in the prepared Pd/ICCP catalyst is determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). The optimized study is investigated in Suzuki cross-coupling reaction between 4-iodoanisole and phenylboronic acid. It reveals that using potassium carbonate in mixed solvent of EtOH: H$_2$O (3:2) in the presence of 2 mol% of Pd/ICCP give 4-methoxybiphenyl in 90% isolated yield at 40 $^o$C. Moreover, in the presence of cetyltrimethylammonium bromide (CTAB) as phase transfer agent, the reaction can preform in water as a sole solvent to give the product in excellent yield under the same condition.
Recently, gas sensor based on the simple change in its resistance in response to the analytes, has been focused as a promising candidate for practical sensing devices. Several nanostructured materials such as carbon nanotube (CNT) and graphene, have attracted considerable attention as alternative sensing materials because of their distinctive characteristics in structural, electrical and mechanical properties. In this study, we studied on hybrid materials based on metal nanoparticle (NP) and polymer-functionalized nanocarbon materials for highly sensitive and selective volatile organic compound (VOC) detection. By taking dichloromethane (DCM) sensing as an example, we successfully demonstrated a highly sensitive detection of DCM vapor at room-temperature operation by means of functionalization of CNT with PMMA and Pt NPs. The response of hybrid sensor to DCM was 69-fold higher than that of pristine SWNT and linearly increased with increasing DCM concentration. The sensing mechanism was elucidated by polymer swelling and catalytic oxidation on the Pt NPs catalyst surface. Besides Pt/PMMA/CNT system, the sensing performance of the sensor based on polymer-coated graphene was also investigated. With the selection of coating polymer, the sensivity and selectivity of the sensor were successlly improved. These results suggest that the integration of nanocarbon materials with polymer and nanoparticle is a promising approach for highly sensitive and selective volatile organic compound detection.
Dye-sensitized solar cell (DSSC) has emerged as one of the most attractive photovoltaic devices because it offers the possibility of low-cost conversion of photoenergy.Ruthenium complex dyes are currently the most efficient dyes. These dyes, however, are costly and hard to prepare in high yields,which have ledto the evolution of metal-free organic dyes.Organic dyes exhibit not only higher extinction coefficient, but simple preparation, structure modification and purification procedure with a low cost. In this talk, an improvement of the performance of the organic dyes as sensitizers for DSSC by fine tuning the dye chemical structures will be presented. A series of organic dipolar compounds forming D-D-π-A type of dyads bearing carbazole-carbazole, carbazole-diphenylamine, carbazole-phenothiazine and carbazole dendrons as D-D moieties were designed, synthesized and investigated. The relationships between structure of these dyes and properties and cell performances will be drawn and discussed. The power conversion efficiencies of the corresponding devices surpass that of the Ru-based device measured under similar conditions, suggesting that the organic dyes based on this type of donor molecular design are promising candidates for improvement of the performance of the DSSCs.
Zinc Ferrite (ZnFe2O4) nanopowders were synthesized by ball-milling technique at different milling times (0 to 24 h) starting from as-combusted powders. The XRD and SEM results ensure significant decrease in particle size of these ferrites with increasing processing time. The distribution of cations including zinc (Zn2+) and ferric (Fe3+) ions was investigated by Zn and Fe K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. Comparing to after-calcined zinc ferrite, both XANES and EXAFS spectra of milled-zinc ferrite powders obviously indicate the translocation of Zn2+ ions from the tetrahedral (A) sites to the octahedral (B) sites and the reverse translocation of some of Fe3+ ions without affecting the long-range structural order. Moreover, the analysis of Zn and Fe K-edge EXAFS spectra exhibit obviously increasing degree of inversion as the particle size decreases resulting in the difference in the magnetic properties of the powders.
Recently, nanofibers attract much interest not only in apparel industry, but also information technology, bio-medical, or environmental fields. In the presentation, I will introduce fabrication and characteristics of highly aligned carbon nanotube (CNT) nanofiber sheets [1-4]. The multiwalled CNTs (MWCNTs) were deposited by chloride-assisted chemical vapor deposition. The length of obtained MWCNTs ranges up to the millimeter scale, and they can easily be spun into yarn by hand with the naked eye. The aligned CNT sheets were formed by stacking CNT webs drawn from spinnable CNT forest. As applications of the CNT sheets I will present strain sensors [5]. In addition to the CNT sheets, we fabricated copolymer of vinylidene fluoride and trifluoroethylene P(VDF/TrFE)(75/25 molar ratio) nanofiber sheets [6]. The highly aligned P(VDF/TrFE) nanofiber webs with high uniformity and smooth surface were obtained by electrospinning. The stretching and annealing process improved their crystallinity. I will also present their characteristics in my presentation.
III-V solar cells have been extensively studied in both theoretical and experimental aspects. The efficiency of the solar cells can be enhanced by the insertion of quantum structures as a result of the quantized energy levels at which photons with energy lower than the host material can be absorbed. A window layer made of a wide band gap material increases the absorption of high energy photons but is transparent to photons absorbed by the next layers. The window layer also decreases the surface recombination. AlGaAs is one of the material used as a window layer and exhibits good optical absorption properties. Furthermore, AlGaAs has a lattice constant nearly matched to GaAs which is a well-known substrate, meaning that AlGaAs can be grown on GaAs with very low defect density. To design and optimize the solar cell structure, numerical simulation is very crucial as the fundamental phenomena of solar cell operation can be visualized prior to the implementation of real devices. In this work, a solar cell consisting of a single AlGaAs/GaAs quantum well with an AlGaAs window layer is simulated to gain the understanding in the influence of the quantum structure and the window layer on the solar cell performance. Other important parameters such as layer thickness and doping concentration are also varied to examine their effects.
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Nanocatalysts have played an important role in biorefinery and advanced biofuel applications. The conversion of cellulosic biomass feedstocks to platform biochemicals, such as organic acids and furans, is one of the key steps in biorefining. In our research group, metal phosphate catalysts have been developed for production of 5-hydroxymethylfurfural from C6 sugar. Incorporating metal species in phosphate networks provides suitable active sites and phases for the reaction. In addition, non-crystalline mesoporous aluminosilicate catalysts with combination of strong and weak acid sites have been developed for conversion of C5 sugar to levulinic acid in one-step without any solvent and H2 addition. The proposed processes proceed efficiently in hot water media, making it highly effective and friendly to the environment.
As for biofuel application, the conversion of vegetable oil and animal fat feedstocks to transportation fuels over heterogeneous catalysts is of interest for new biofuel industry. Such process is not only leading to lesser amount of imported petroleum and higher energy security of Thailand, but it is also valorizing byproducts from the country agricultural sector. We have developed the catalysts for the production of green diesel, a synthetic alkane, known to be one of the candidates for future energy. The process can be accomplished via deoxygenation over NiMoS2/Al2O3, Ni/Al2O3, and Co/Al2O3 catalysts with high product yield at above 95%. Hydrogen, which is an important chemical for the deoxygenation, can effectively be achieved from steam reforming of oxy-hydrocarbons over Cu- and Ni-based spinel nanocatalysts. The integration of all processes mentioned above would lead to new technologies for biorefinery and biofuel industries of Thailand.
A simple thermal oxidation has been used for fabricating nanostructured NiO/NFs electrodes at a temperature lower 1000 ͦC in air. The results obtained from x-ray diffraction (XRD) and scanning electron microscope (SEM) have shown the structure and morphology of Ni foam (NFs) before and after oxidation. The electrochemical characterization measurements have shown that the NiO/NFs electrodes are sensitive to UV light, as observed from the increase in measured current. The effect of UV-irradiation will be discussed.
Keywords: NiO electrode, UV light, Electrochemical, Thermal oxidation
Deoxygenation of vegetable oil has been employed as one of important processes for highly efficient production of renewable green diesel (bio-hydrogenated diesel). Moreover, to avoiding sulfur contamination in fuel product, metal oxides, metal phosphides, and metal nitrides have become attractive. In this work, bimetal oxide catalysts over supported alumina were selected to produce diesel-liked hydrocarbons via deoxygenation of oleic acid under facile condition. All catalysts were prepared by incipient wetness impregnation and characterized by XRD, SEM, TEM and BET. Furthermore, effects of reaction time and temperature were studied in a batch reactor (300 mL in size) under N2 pressure. The results revealed that NiMo/Al2O3 catalyst exhibited a high conversion over 90% and the contribution of decarboxylation (DCO2) enhanced by increasing both reaction time and temperature. In addition, saturated hydrocarbons and stearic acid were also detected. These result indicated that dehydrogenation and hydrogenation occurred during the reaction. Therefore, all active phases (MoO3 and NiMoO4) of Ni doped Mo oxide catalyst were deeply investigated using DFT method with ethane as a model compound. The calculations emphasized that both of metal oxide phases could produce unsaturated compounds through dehydrogenation by taking hydrogen atoms out to the surface. Interestingly, the NiMoO4 phase contained numerous vacancies on the surface, and consumed less energy for the reaction in respect with MoO3. As a results of that, it would be a better phase to produce unsaturated products compared to MoO3 phase. However, the hydrogen atoms were not enough for hydrodeoxygenation(HDO) pathway because of low selectivity of C18 compared with C17 in liquid products.
The external magnetic field was applied in a packed-bed reactor based on the concepts of green and sustainable production of alternative fuels through CO2 hydrogenation reaction. Accordingly, the roles of magnetic flux density and magnetic field direction on the performance of Fe-Cu/MCM-41 catalyst with intrinsic magnetic property were investigated and compared to that of without magnetic field. It was found that magnetic field strongly affected the activity of catalyst, both CO2 conversion and product selectivity. Over 10Cu–10Fe/MCM-41 catalyst, magnetic field remarkably promoted CO2 conversion, especially in the north-to-south (N-S) direction (1.8 times higher than that of without magnetic field at 260oC). With increasing magnetic flux density, CO2 conversion was increased followed the order of 27.7 mT > 20.8 mT > 0 mT in each magnetic field direction. Moreover, under the magnetic field conditions which gave the highest CO2 conversion, it was more favorable for CH3OH formation. CH3OH space time yield with magnetic field was 1.5 times higher than that of without magnetic field. The improvement of catalytic activity by the magnetic field application was described by mean of the reduction of apparent activation energy (Ea). With magnetic field, the apparent activation energy was decreased for approximately 1.18 times compared to that of without magnetic field. This outstanding performance was attributed to the fact that magnetic field could facilitate the adsorption ability of reactant gases on magnetized catalyst surfaces, leading to the increase of catalytic CO2 hydrogenation and selective conversion to CH3OH, and lowering of the activation energy.
Cellulose, extracted from plant, has been widely used in various purposes especially in paper industry. In industry, cellulose is modified by many organic and inorganic substances in order to improve the quality like smoothness, whiteness and mechanical strength. However the deterioration of the paper according to the degradation of cellulose has been found in many ancient documents and paintings. The causes of cellulose alteration are from biodegradation, photodegradation, acid hydrolysis and oxidation. In this research, filter paper, a representative of cellulose fiber, was coated by SiO2 to improve its stabilities. The surface of the cellulose was initially modified by various methods as follows:
1. esterification by polycarboxylic acids like tartaric acid (TA) and butanetetra-carboxylic acid (BTCA) to obtain FIL-TA and FIL-BTCA respectively
2. etherification by sodium monochloroacetate to obtain FIL-MCAA
3. coating by carboxymethylcellulose to obtain FIL-CMC
Then each of the modified filter papers was subsequently coated by SiO2. All paper samples were characterized by SEM/EDS, XRD and TGA. The Smoothness (Bekk method), air resistance (Gurley method) and bursting test of paper were also performed. All coated papers were then placed in saturated curcumin solution for 20 min. The stability of this natural dye on the paper was tested against UV-A radiation (= 315-400 nm) for various time interval. The changes in the color parameters L, a, and b were measured; L index of color represents black-to-white color, a index represents green-to-red color, and b index represents blue-to-yellow color. The overall change in color indices of the coated papers can be calculated as the following equation:
∆E = ((∆L2)+(∆a2)+(∆b2))1/2
where ∆L, ∆a, and ∆b are the differences between the values of the color indices before and after radiation. The TA-SiO2 paper shows the lowest ∆E value.
The new composite materials of TiO2 nanoparticles and biomolecules are promising to provide the potential alternative for improving the photocatalytic activity by merging the ability and features of both material types. In this research, the unique visible light-responsive chlorophyll and magnesium (Mg) co-modified P25 catalyst (Chl-Mg/P25) was successfully synthesized by using a simple incipient wetness impregnation method. Chlorophyll and Mg were loaded on P25 nanoparticles with an attempt to enhance photocatalytic efficiency and inhibit the recombination of photo-induced electron-hole pair. The existences of chlorophyll and Mg on P25 were verified by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The synthesized catalysts were tested for photocatalytic degradation under visible light by using Rhodamine B (RhB) as a probe molecule and the effect of chlorophyll and magnesium on photocatalytic degradation were investigated. It was found that the activities of catalysts were in the order of: P25 < Mg/P25 < Chl/P25 < Chl-Mg/P25. The addition of chlorophyll, Mg, and chlorophyll-Mg in the catalyst could promote the photocatalytic efficiency for approximately 1.9, 1.1, and 2.3 times of P25, respectively. These outstanding photocatalytic activities could be attributed to the enhancement in visible light harvesting from chlorophyll, the higher charge separation efficiency from Mg, and the synergistic effect between chlorophyll-Mg and P25 nanoparticles. Moreover, Chl-Mg/P25 catalyst also showed a good recyclability and high stability after seven repeated experiments.
Nanomaterials have enormous economic potential for technical and medical applications due to their new properties acquired on the nanoscale. However, given multiple exposure pathways from the raw material production to the final product and its disposal, it is necessary to understand where and how nanomaterials can be released, and how this release can lead to exposure of workers, consumers and the environment. Once we understand release and exposure, we can design and implement adequate measures to protect humans and the environment from potential exposure along these value chains. Focusing on release reduction from materials, products and during production processes is a very efficient approach to reduce risks of nanomaterials because no release means no exposure, and without exposure, even a dangerous material cannot lead to negative health effects.
The management of nanomaterial-related risks poses some special challenges, such as uncertainties related to human hazard data and exposure assessment; as well as insufficient communication of risk-relevant information along the value chain. Good management strategies need to identify adequate and cost effective solutions for such safety and health challenges. Risk mapping is a novel tool for addressing safety, health and environmental challenges in companies, from R&D over production facilities all the way to the interaction with end-consumers. Risk mapping identifies the various elements in a company and along the value chain that need to be addressed for a complete risk management, such as product development and testing, workplace assessments, facility design, and training of staff. These elements then are mapped onto the business processes to integrate the health and safety approach into the corporate management and effective company policies.
This talk will provide an overview of how risk mapping can help to successfully address nanomaterial specific challenges and what role release management by smart design can play in risk reduction.
A survey of 512 students from two local universities revealed that perception of nanotechnology regarding its importance to Thailand's economy and personal welfare was overall positive. Students especially 'agreed' or 'strongly agreed' with survey questions that focused on government support and regulation of nanomaterials and nano-labelling and were overwhelmingly in favor of developing a nano-safety program in Thailand. Most students believed that nanotechnology-based products would be cheaper, would improve the quality of life and aid in producing high technology jobs— even though knowledge about nanotechnology by a majority of students was still in the formative stages (not different from similar surveys done in other parts of the world and not unexpected considering the newness of nanotechnology). Demographics included gender, field of study (engineering & sciences vs. social sciences), nanotechnology experience, nanotechnology knowledge and home university.
Taiwan Nanotechnology Program has been launched from 2003 up to now in which nano-EHS program remains one of the main projects collaborated by many different agencies, including Taiwan MOST, EPA, ILOSH, MOHW, BSMI, universities and research institutes (ITRI, NHRI etc.). Through inter-agency efforts, progress has been made in core facility establishment for nanomaterial characterization, certification of nanoproducts as nanoMark products, promulgation of regulations for registration of new chemicals, issuing guidances for the Assessment of Hazardous Chemicals and CCB (Chemicals Control Banding) Management of Chemicals, and the Registration of Nanomaterial-containing Food utensils, Containers and Packages…etc. It can be said that the commercialization of nanotechnology-related products is being emerged and promoted while it is being regulated at well.
To support nanoproduct commercialization and regulation, research progress has been made in the development of Nanoscale Reference Material, exposure assessment of nanotechology workplaces, development of personal nanoparticle samplers, development of hiighly Raman-enhancing substrates based on silver nanoparticle arrays with tunable gaps, in-vitro studies using impedance-based Real-Time Cell Analysis detection platform, in-vivo studies using the whole body exposure chamber and efficient powder dispersion system etc. The progress in regulations and researches has been documented and archieved in Taiwan Nanotechology EHS Database (http://ehs.epa.gov.tw/Home/EN_F_Home_Index) which serves as the platform for the exchange of information and communication among different stakeholders and for the promotion of collaboration among international communities.
Nanotechnology has been implemented in the construction industry and one application is the use of photocatalytic cement which is Portland cement containing titanium dioxide (TiO2) nanoparticles. Photocatalytic cement makes the surface white without the need of paint. TiO2 acts as a biocide making the surface selfcleaning.
However, TiO2 is a human carcinogen (Group 2B; IARC) and construction workers are exposed to airborne particles while handling cement. The deposition of inhaled particles is influenced by physical and chemical properties such as particle size and density, shape and penetrability, surface area, electrostatic charge, and hygroscopicity. Portland cement is well characterized fine powder with an aerodynamic diameter in the range of 0.05-5 μm. Photocatalytic cement has not previously been described in terms of physical characteristics and chemical composition. This cement might have a smaller aerodynamic diameter, changing the lung deposition mechanisms from that of regular cement. Nanoparticles have been shown to accumulate in the lungs, especially in the alveoli, and be translocated into blood circulation where they are transported to different target organs (lymph nodes, kidney, liver, heart, and brain). Physical parameters for cement can be obtained using an aerosolizing nanoparticle generator system. Our research aims are to (1) characterize
photocatalytic cement and (2) compare the parameters to regular cement using this aerosolizing system.
Photoemission electron spectroscopy (PES) is a powerful technique that provides information about chemical composition and electronic structure of a material surface. In this talk, the basic concepts and methods of PES will be introduced. The PES experiment facilities at the Siam Photon Laboratory, Synchrotron Light Research Institute (SLRI), will be overviewed. Examples for its applications will also be given and discussed to demonstrate the technique capabilities.
The attractive properties of diamond-like carbon (DLC) films consist of chemical inertness, high hardness, excellent tribological behavior, optical properties, and biocompatibility.1,2 These properties make them reasonable for using in a broad range of the industrial applications. For example, the DLC films are used for magnetic storage disks, automotive parts, biomedical devices, cutting tools, and solar cells.1-3 In the last decades, many research groups published the articles of 5,555 in an international journal based on Scopus database which is related to the DLC films through improved by doping with a “hetero element”.4 The data plays a significant role in the increment of the DLC applications and fields of studies in future. Currently, the combination of near-edge X-ray absorption fine structure (NEXAFS) and the X-ray photoemission electron microscopy (X-PEEM), so-called spectromicroscopy method at the Beamline 3.2Ua/b, enables us to make a sensitive evaluation of the surface structure together with the chemical states. It is a necessary result because it opens up the way to examine the classification of the DLC films for further understanding of chemical characteristics.
The investigation of the local geometric and electronic structure of probing element in bulk samples is the most extensive field of application in X-ray Absorption Spectroscopy (XAS). XAS consists of two main regions which are X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). The former region is used to explain the local geometry and oxidation states of selected element in a sample whilst the latter one is used to address the local structure around probing element in samples. In my talk, the introduction of XAS, the XAS beamlines at the Synchrotron Light Research Institute, THAILAND, and applications of synchrotron-based XAS on advanced functional materials such as carbon-ferrite composite nanofibers [1] and thermoelectric materials will be introduced in order to obtain the accuracy of their locally structural information which cause different properties in these materials.
BL1.3W: SAXS/WAXS (Small/Wide angle x-ray scattering) at SLRI is a dedicated beamline for nano-structural investigation of material that has electron density fluctuation on the length scale under 100 nm. High intensity x-ray is obtained by incorporating the synchrotron radiation from a wiggler insertion device and a double multi-layers monochromator. The beam is focused by a toroidal mirror while three four blades slit systems were used for collimation purpose. Rayonix SX165 CCD detector having the diameter of 165 mm was employed as the x-ray detector.
The beamline is equipped with sample holder where the temperature of 15-200 °C can be controlled. The sample situated in air environment can be powder, solid or liquid state. A temperature controlled tensile machine is also available for in-situ study of nano structure of material under tension. The sample to detector distance can be varied from 0.1 to 4.8 m to cover the q-range of wide and small angle x-ray scattering 0.08<q<35 nm-1.
SAXS can be used to study several types of material. For nano particle in colloidal system, the size, size distribution, fractal dimension can be obtained. For protein solution, SAXS offer folding/unfolding, aggregation, shape and conformation. For polymer system, orientation and period of periodic domain in block copolymer, lamellar structure of semicrystalline polymer can be extracted. The setup for WAXS measurement is also possible for the study of crystal structure such as phase identification and calculation of crystallinity.
Nanomaterials have a vast range of applications in various fields due to their superior properties. There are a number of methods for nanoparticle-thin film coatings, for example spray pyrolysis, electrodeposition, spin coating and sol-gel process. However, these methods are either time consuming or require the use of toxic substances. The sparking method can be used to prepare nanoparticles and nanoparticle-thin films by applying a high voltage across any two metal wire tips. This talk will cover the effects of electric and magnetic fields on film morphology and crystalline phase formation. Preparation and characterization of ZnO, TiO2, In2O3, FeN nanoparticle-thin films will be presented. It was found that the electric and magnetic fields enhanced the growth rate and uniformity of the films, whereas the magnetic field also altered the phase formation. Investigations of the sparked nanoparticles or nanoparticle-thin films as a photo-catalyst in dye-sensitized solar cells, a self-cleaning glass and a volatile organic compound sensor will be reviewed. A commercial lab-scale instrument of the sparking method from Nanogeneration Co., Ltd. as a spin-off company will be also demonstrated.
In this study, CeO2photocatalyst was modified by composite with SiO2 to increase efficiency and improve photocatalytic activity. The as-prepared SiO2 particles have been incorporated into the precursor mixture of CeO2 by homogeneous precipitation and subsequent calcination process. The phase compositions of CeO2 before and after compositing with SiO2 were identified by X-ray diffraction (XRD). The morphology and particle size of CeO2/SiO2 composite was analyzed by high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). The results showed SiO2 spheres with the particle size approximately 100–120 nm, and a uniform layer of CeO2 nanoparticles with a diameter of about 5–7 nm that were fully composite to the surfaces of SiO2. The X-ray photoelectron spectroscopy (XPS) technique was carried out in order to characterize the change in valence state and composite characteristic by shifted peaks of binding energies. The photocatalytic activity was studied through the degradation of Rhodamine B in aqueous solution under visible light exposure. The highest photocatalytic efficiency of CeO2/SiO2 composite was also obtained. To explain the high photocatalytic efficiency of CeO2/SiO2 composite, the proposed mechanism involves the high surface properties of the CeO2/SiO2 composite, as measured by Brunauer–Emmett–Teller (BET) method.
Keywords: Composite materials, CeO2, Rhodamine B, Silica, Photocatalysis
Glasses are source of material have properties like low cost, easy to prepare, high transparency at room temperature, hardness along with sufficient strength, excellent electrical resistance, absence of the grain boundaries and continuously variable composition for the optical applications. Glasses doped with Lantanide ions (Ln3+) can be well developed as luminescence materials because of high emission efficiencies, corresponding to 4f–4f and 4f–5d electronic transitions in the Ln3+. The 4f–4f transition gives an especially sharp fluorescence patterns from the ultraviolet to the infrared region, because of shielding effects of the outer 5s and 5p orbitals on the 4f electrons. Investigation of the optical and luminescence properties of the Ln3+ doped into various glasses have been found great attention due to their feasible properties, (including intense emissions in the visible and near infrared region) and vast applications in the field of lasers, scintillators, sensors, light converters, hole burning high-density memories, optical fibers, amplifiers, and three dimensional display devices. In this work, optical and luminescence from Ln3+ doped glasses and their applications have been explained and the effect of some nano-particles on luminescence properties have been discussed.
The objective of this work was to use the spinning waste in form of short fibres for the
preparation of nano size fillers in nanocomposite applications. The present paper concerns with the
jute fibres as the source to produce nanocellulose by high energy planetary ball milling process
and its potential applications as fillers in biodegradable nanocomposite plastics used in
automotives, packaging and agriculture applications. Influence of various milling conditions like
nature of milling (i.e. dry or wet), milling time and ball size are studied on the particle size
distribution and morphology of jute nanoparticles obtained. Wet milling in the deionised water
resulted into particle size refinement below 500 nm with narrow size distribution after 3 hours of
milling at the cost of small amount of contaminations introduced from milling media.
A one-step “top-down” process was proposed in this work to obtain nanoparticle products of tetragonal barium titanate (BaTiO3; BT) with highly accurate stoichiometry and morphological control. A micrometer-sized BT precursor significantly decreases to nanometer-sized product particles and its irregular shape changes to nearly spherical with narrow size distribution via surface active etching. Both XRD and Raman results of BaTiO3 nanoparticles indicated a tetragonal crystal structure. The 77.5 ± 2.5 nm sized BaTiO3 powder product still polarized spontaneously at room temperature and the ferroelectric phase transition was confirmed at around 127 °C. Dielectric permittivity was found to be ~ 166.42 by Landauer-Bruggeman effective medium approximation (LB-RMA). Experimental procedures revealed a possible process mechanism observed within the etched surface and Oriented-attachment growth models, and this demonstrated approach could be used as an excellent platform for preparing advanced ceramic nanoparticles.
The magnetite Fe$_3$O$_4$ nanoparticles have been synthesized successfully by hydrothermal method in the egg white solution. The egg white solution was used as a surfactant and it can also reduce impurity phase in samples. This work aims to study the influence of different reaction temperatures (160-220 $^o$C) on the structure and magnetic properties of the synthesized Fe$_3$O$_4$ nanoparticles. The results of X-ray diffraction (XRD) and selected area electron diffraction (SAED) indicate that the synthesized Fe$_3$O$_4$ nanoparticles have the inverse cubic spinel structure without the presence of any other phase. The particle sizes of samples are in the range of ∼10–50 nm as revealed by transmission electron microscopy (TEM). X-ray absorption near edge structure (XANES) spectra show the oxidation state of Fe$^{3+}$ and Fe$^{2+}$ in the samples. The hysteresis loops of the Fe$_3$O$_4$ nanoparticles exhibit superparamagnetic behavior at room temperature for all conditions. The saturation magnetization increases with increasing reaction temperature except at 220 $^o$C.
Mosquito repellents can help to protect against mosquitoes which transmit many disease such as Zika, malaria, dengue and other viral diseases [1,2]. Recently, people have used the products which made of both chemical and natural mosquito repellent agents [3]. However, the fast evaporation of active ingredients in mosquito repellents limits the time protection against mosquitoes [3,4]. To prolong the release time of mosquito repellent agent, the encapsulation technique can be applied. In this study, polymeric nanocapsules containing mosquito repellent agents, i.e. N,N-diethyl-m-toluamide (DEET) and eucalyptus oil were prepared by oil-in-water precipitation method. The hydrodynamic diameter and particle size distribution of prepared nanocapsules were characterized using dynamic light scattering method (DLS). Protection time against mosquito bites was investigated at various storage time. Moreover, the primary skin irritation of the nanocapsules were studied in using rabbit model. DEET-based mosquito repellent and eucalyptus oil-based mosquito repellent nanocapsules provided up to 12 hours and 3 hours of protection against mosquitoes, respectively. The polymer encapsulation is one effective approach to reduce the risk of mosquito bite and consequently prevent from many mosquito-borne diseases.
Density functional theory (DFT) and time dependent DFT (TDDFT) were used to study on electronic and photoelectrochemical properties of monascus, cochineal, lac insects and anthocyanin dyes. The low-cost dye-sensitized solar cells (DSSCs) utilized by crude and pre-concentrated anthocynins extracted from mangosteen pericarp, roselle, red cabbage, Thai berry, black rice, blue pea and purple corn were fabricated. The ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photo-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs. Nanoporous carbon microspheres from carrot juice and mesoporous honeycomb-like carbon structure from mangosteen peel were used as counter electrodes for DSSCs.
References
[1] Chaiamornnugool, P., Tontapha, S., Phatchana, R., Ratchapolthavisin, N., Kanokmedhakul, S., Sang-aroon, W., Amornkitbamrung, V., “Performance and stability of low-cost dye-sensitized solar cell based crude and pre-concentrated anthocyanins: Combined experimental and DFT/TDDFT study,” Journal of Molecular Structure, 1127, pp. 145-155. (2017)
[2] Phinjaturus, K., Maiaugree, W., Suriharn, B., Pimanpaeng, S., Amornkitbamrung, V., Swatsitang, K. “Dye-sensitized solar cells based on purple corn sensitizers,”
Applied Surface Science, 380, pp. 101-107. (2016)
[3] Maiaugree, W., Lowpa, S., Towannang, M., Rutphonsan, P., Tangtrakarn, A., Pimanpang, S., Maiaugree, P., Ratchapolthavisin, N., Sang-Aroon, W., Jarernboon, W., Amornkitbamrung, V., “A dye sensitized solar cell using natural counter electrode and natural dye derived from mangosteen peel waste,” Scientific Reports, 5, art. no. 15230, (2015)
[4] Lowpa, S., Pimanpang, S., Maiaugree, W., Saekow, S., Uppachai, P., Mitravong, S., Amornkitbamrung, V., “Nanoporous carbon microspheres from carrot juice used as a counter electrode for a dye-sensitized solar cell,” Materials Letters, 158, pp. 115-118. (2015)
[5] Sang-Aroon, W., Laopha, S., Chaiamornnugool, P., Tontapha, S., Saekow, S., Amornkitbamrung, V., “DFT and TDDFT study on the electronic structure and photoelectrochemical properties of dyes derived from cochineal and lac insects as photosensitizer for dye-sensitized solar cells,” Journal of Molecular Modeling, 19 (3), pp. 1407-1415. (2013)
[6] Sang-Aroon, W., Saekow, S., Amornkitbamrung, V., “Density functional theory study on the electronic structure of Monascus dyes as photosensitizer for dye-sensitized solar cells,” Journal of Photochemistry and Photobiology A: Chemistry, 236, pp. 35-40. (2012)
Titanium dioxide (TiO$_2$) is a promising material for versatile applications, i.e., air-water purification, anti-fogging, anti-corrosion. However, those applications are limited to the available of the appropriate light source. To overcome this problem, modification with energy storage substances such as WO$_3$ [1], Phosphotungstic acid [2] and TiO$_2$-V$_2$O$_5$ [3] is applied. An energy storage system is composed of electron generating source (i.e., TiO$_2$) and energy storage substance. The mechanism of energy storage in the air states that TiO$_2$ generates photo-excited electrons under UV light and those electrons transfer to energy storage substance. Those stored electrons release and carry on the cathodic reactions in the dark as shown in Fig. 1. The energy storage system can be used as multipurpose materials for many aspects i.e. anti-corrosion, pollutant decomposition, coating substances for smart window. The photo catalytic electron can subsidize the electron deficiency that metal lose to the environment [3], while coincident hydroxyl radical, which is a product from water oxidation by photo-excited holes can decompose the pollutant [4]. However, the efficiency of the system is relied on the contact between TiO$_2$ and an energy storage substance. The use of conduction polymer to bridge the electron generating source and the energy storage substance has proved to be effective and overcome the aforementioned problem [4]. In this presentation, we demonstrate the use of the hybrid materials as energy storage catalysts. The photocatalytic oxidations of toluene in a gas phase and methylene blue are given as examples.
Keywords: Impedance spectroscopy; Lithium iron phosphate; Electronic conductivity;
The ever-growing public and now commercial sentiment supporting the widespread adoption of low and zero-emission vehicles, it is unsurprising those Li-ion batteries which currently assume the bulk of the cost of electrified vehicles. The main challenge is obtaining cathode material with high energy density, high safety, low cost, environment friendly and long cycle life. Lithium iron phosphate (LiFePO4, LFP) has proved itself to meet these requirements. However, the key limitation has been extremely low electronic conductivity, until now believed to be intrinsic to this family of compounds. Cation doping is one of the most promising methods in improving conductivity of this material. Here, we study the electrical properties of Co-doped LFP samples synthesized by solid state reaction. The phase composition was identified by X-ray diffraction confirming the single phase of LFP. The unit cell volume of LFP obtained by Rietveld refinement method shows that it decreases with increasing Co contents. The electric properties of the samples were measured as a function of temperature and doping content by Impedance spectroscopy technique. The conductivity of LFP sample is dependent on Co doping level.
Acknowledge: PK acknowledges the financial support from the Thailand Research Fund and Human Resource Development in Science Project (Science Achievement Scholarship of Thailand, SAST)
By using KOH as the chemical activating agent to prepared activated carbon from pineapple leaf fiber waste as the carbon source. The structure, morphology and the surface functional groups of the as-prepared activated carbon were investigated by X-ray diffraction (XRD), field emission scanning electron microscope equipped with energy dispersive X-ray spectroscopy (FESEM-EDX), X-ray photoelectron spectroscopy (XPS), respectively. The electrochemical behavior and performance of the as-synthesized activated carbon electrode were measured by the cyclic voltammetry (CV) and the electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4 electrolyte solution by using the three electrode setup. The activated carbon electrode exhibited the specific capacitance of 131.3 F g-1 (5 mV s-1) with excellent cycling stability. The capacitance retention after 1,000 cycles was about 97% of the initial capacitance at a scan rate of 30 mV s-1. Given good electrochemical properties along with the simple accessibility make this activated carbon electrode a promising candidate in future large-scale production of the electrochemical capacitors (ECs).
Keywords: Electrochemical capacitors, Biochar, Activated carbon, Pineapple leaf fiber, Agro-waste base materials
The rapidly growing demand for renewable energy storages, there has been growing the interest in nanomaterials from biomass waste. One of the key to improve performance of the nanomaterial depends on the structure of materials. The rice husks (RHs) are the most agricultural biomass waste found in Thailand. They are source of SiO2 and carbon nanostructure. Nano-silica (SiO2) and activated carbon (AC) can be extracted from RHs employing a simple procedure without any destruction the nanostructures, which can provide high surface area and high electrical conductivity. In this work, SiO2/AC nanocomposites were synthesized by calcination under Argon atmosphere at temperatures between 400 and 1,200 °C. The chemical and crystal structure of SiO2/AC nanocomposites were identified by SEM, TEM, XRD and FTIR techniques, respectively. The XRD results show crystalline and amorphous phases of silica and carbon at different calcination temperature. The FTIR results show the intensity of the major chemical groups of SiO2 and the aromatic hydrocarbons peak of AC. Moreover, the results also show the relationship between carbon allotropes and calcination temperature. The electrochemical properties of SiO2/AC nanocomposites in lithium ion batteries depend on chemical groups of SiO2 and the aromatic hydrocarbons of AC.
Acknowledgements: YK acknowledges the financial support from Young Scientist and Technologist Programme, NSTDA (YSTP: SCA-CO-2559-2446-TH)
Keywords: Rice husks; Silica; Activated carbon; energy storage.
Rechargeable lithium ion batteries are amongst the most advanced electrical energy storage system available today. Many families of compounds have been developed for use as cathode materials in Li-ion batteries such as layered oxides LiMO2 (M = Co, Ni, Mn, or V), manganese spinel (LiMn2O4), and phospho-olivines LiMPO4 (M =Fe, Mn, Co, or Ni). Lithium iron phosphate (LiFePO4) have become the most interesting cathodes materials for lithium ion batteries because of their inexpensive, environmental friendly, high theoretical capacity (170 mAh/g) and long cycle life and high safety. However, LiFePO4 inherently show poor electronic conductivity causing low rate performance . Many approaches have been used to improve conductivity of this material, e.g. carbon coating and nano-sizing. These also include isovalent doping which significantly increasing conductivity of the material.[1-3] Co is an element widely chosen as dopant due to the increasing of rate capability. However, there is not clearly evident showing mechanism of Co2+ incorporating with the improving rate capability during batteries operation. Here, we study the electronic structure change of Co2+-doped LiFePO4 materials during battery operation by in-situ X-ray absorption near edge structure (XANES). The materials were synthesized by the solid-state reaction. The single phase of LiFePO4 was confirmed by X-ray diffraction. The in-situ Co and Fe K edge XANES were measured during charge-discharge to observe the oxidation state of Co2+ . The XANES result indicate that the oxidation state of Co2+ do not incorporate in phase transition during batteries operation. It only provides the improvement in conductivity of LiFePO4 material.
Here, we introduce a new technique, called rapid convective deposition, to fabricate planar perovskite solar cells. This technique uses a reclining blade to draw a liquid droplet across a substrate thus advancing thin film can be deposited on a substrate. Thickness and morphology of the thin film can be controlled by deposition speed and blade angle as well as liquid volume and concentration. Unlike the conventional spin coating, the convective deposition consumes much less material in fabrication process. Recently, we have demonstrated high efficiency and low cost fabrication of perovskite solar cell with ITO/PEDOT:PSS/Perovskite/PCBM/TiOx/Al structure. Except the ITO and Al metal electrode, all the solid films were deposited layer by layer via the convective deposition. In addition, the low temperature treatment less than 120 oC were conducted in this experiment. Recently, more than 10% solar cell efficiency has been achieved. Furthermore, this rapid and scalable deposition technique has been used in fabrication of electrochromic windows, polymer/hybrid solar cell and anti-reflective glass.
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Smell, taste, appearance and flavor are central to the value of agricultural products, especially fruits and their post-harvest spin-offs such as teas, coffees and wines. In specific, the uniqueness of a wine depends on types and ratio of such aroma molecules collected in the leaves or fruits during the growing seasons, which is related to many external factors such as soil conditions, fertilizers, irrigation, sun light and climate. Aroma management is a complex task involving various kinds of day-to-day activities that require year-long vigilant attention from the people concerned. Recently, modern technologies, for example, “precision farming”, have been introduced to plantation at the farm level. We have developed several technologies for farm management. The system features: (1) wireless sensor networks to monitor microclimate conditions such as solar energy, temperature, humidity, rain, air mass flow and pressure, soil water contents throughout the farm area; (2) plant monitoring system to monitor various parameters for proper irrigation management and analysis of plant growth; (3) web-based farm monitoring tools that farmer can access all information over the farm intranet/internet; (4) daily activities monitoring in which GPS-tracking systems follow activities of all equipments in the farm; (5) electronic nose system to monitor soil abundance, fruit growth and development of the fermented wines. This system was tested at various sites such as GranMonte vineyard in Nakhon Ratchasima, paddy in Kanchanaburi, HCF eggplant farm in Chiang Rai and Edamame farm in Chiang Mai. We have integrated both commercial and in-house technologies to build up such smart farm system. For wireless sensor networks, we have developed microclimate monitoring system based on IEEE 802.15.4, or the so-called ZigBee, using the mesh topology. For the monitoring of fruit and its post-harvest products, electronic nose has been demonstrated that it can be helpful tool both in the field (vineyard) and winery. By that, grape ripeness and fermentation stage can be tracked, leading to better quality control of the products.
In this paper, gold nanoparticles were synthesized by means of a green approach with T. triandra leaf extracts under different conditions. No additional reducing or capping agents were employed. The gold nanoparticles were characterized using UV-visible spectrometry, transmission electron microscope, X-ray diffraction and Fourier transform infrared spectroscopy. Gold nanoparticles that had been synthesized at temperatures of 80oC were further used to treat rice (Oryza sativa L.) grains at different concentrations (0, 10, 100, 500, 1000, 2000 mg/L) for one week. While germination percentages were high (95 to 98.38 %), a slight decrease in root and shoot lengths relative to the control was observed. Phytotoxicity results indicated that the plant synthesized gold nanoparticles were of minimal toxicity to rice seedlings. Increases in cell death, hydrogen peroxide formation and lipid peroxidation in roots and shoots were noted. However, these increases were not statistically significant(p≤0.05). The overall results confirmed that T. triandra synthesized gold nanoparticles are biocompartible and can be potentially used as nanocarriers in agriculture.
A highly sensitive turn-on fluorescent sensor for cyanide was developed based on benzylidenes containing methylindolium group. Three benzylidene derivatives were synthesized from the condensation reactions between benzaldehyde derivatives and methyleneindoline. Only one of these three derivatives shows strong visible blue fluorescence selectively to cyanide which was clearly observed in submicromolar range. The detection of cyanide with this compound was optimized in aqueous media using a non-ionic surfactant, Triton X-100 and sonication technique to give very low limit of detection in subnanomolar range. The compound was also developed into a paper-based and gel-based sensing kits for on–site naked eye detection of cyanide in micromolar range under black light illumination (360 nm).
Fluorescent-based sensors have received extensive attention due to its highly sensitive and rapid sensing ability to detect metal ions. In this study, we have developed a new BODIPY derivative, mTBODdiSalic for detection of metal ions in aqueous media. The probe has been synthesized from 2,4-dimethylpyrrole and 5-formylsalicylic acid in 4 steps and fully characterized with NMR and Mass spectrometry. mTBODdiSalic displays a maximum absorption and emission at wavelength 642 and 662 nm which appear as blue color in daylight and pink under fluorescent black light, respectively. Among 19 various metal ions, mTBODdiSalic's emission was selectively quenched by the addition of Cu$^{2+}$ and Al$^{3+}$ ions. Moreover, mTBODdiSalic could react with Au$^{3+}$ to afford maximum absorption wavelength shift from 642 into 573 nm (purple color) along with maximum emission wavelength shift from 662 into 596 nm (orange fluorescence). Therefore, mTBODdiSalic could be used to visually discriminate between Au$^{3+}$ over other cations in aqueous solution under a UV−vis lamp.
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Silver nanoparticles (Ag-NPs) were impregnated on the surface of coffee grounds (CF) (referred to as Ag-CF hybrid, having 0.44 and 0.80 % weight of Ag), for achieving water disinfection in a batch set-up. First, Ag-CF was synthesized by coating with nature-inspired nanoparticles that containing Ag-NPs on their surface. Subsequently, Escherichia coli and Staphylococcus aureus cells-killing experiments were performed in a 1000 ml flask with Ag-CF hybrid (batch-mode) for 15 min. Experiment with E. coli using 50 mg Ag-CF hybrid having 0.80% weight of Ag per 1 ml cell suspension showed that, 106 CFU/ml of cells was completely disinfected within 15 min contact time. The visible colony was zero. For S. aureus, water having 106 CFU/ml S. aureus could not be completely killed in all treatments. A maximum inactivation of S. aureus was 98.75% for 50 mg Ag-CF hybrid having 0.80 % weight of Ag per 1 ml cell suspension at 15 min. Moreover, the pH and Ag concentration in the water after adding CF were 4.61 and 86 μg/L, respectively. Hence, water disinfection can be easily achieved in a batch manner within 15 min, with our Ag-CF addition.
Keywords: Silver nanoparticles, Antibacterial, Escherichia coli, Staphylococcus aureus
A composite film of Cassava root and Poly (3,4-ethylenedioxy thiophene):polystyrene sulfonate (C/PEDOT:PSS) was prepared as a high electrocatalytic material for the counter electrode (CE) of a dye-sensitized solar cell (DSSC). The effect of sintered of Cassava root under Ar atmosphere at 1000 $^o$C was intended for increasing the conductivity, and the PEDOT:PSS was used for a strong adhesion of the composite film to the FTO-Glass substrate. The DSSC with the C/PEDOT:PSS composite CE exhibited a high energy conversion efficiency (η) of 9.54% under full sunlight illumination condition of 100 mW/cm$^2$, comparable to that of the DSSC based on the Pt electrode (10.03%). The composite catalytic film of C/PEDOT:PSS is a low-cost alternative for replacing the conventional and expensive Pt film.
In this work, high efficient sensor array for sweet taste classification was demonstrated for electronic tongue application. The sensor array was fabricated by electrochemical sensors based on multiwall carbon nanotube (MWCNT) paste blending with modify electroactive species including either nickel oxide (NiO), copper oxide (CuO), cobalt phthalocynine (CoPC) or iron phthalocyanine (FePC). The sensor arrays was design to response to varieties of sweet. Samples used for sweet taste classification had the same sweetness level with different kinds of sweeteners including of glucose, fructose, maltose, sucrose and honey. Cyclic voltammogram (CV) of the modified MWCNT paste sensor was performed in the sweet taste solutions in the range of 0 to 1 V. The CV feature of the metal phthalocyanines and metal oxides can be modified due to dominant oxidation and reduction of sugar molecule catalyzed by the blended materials. To classify sweet taste, input variables of principal component analysis (PCA) were extracted from the measured CV. The PCA results were clearly separated indicating that the sweet samples can be clearly classified by this modified sensor array. The relative positions of the data clusters can approximately relate to molecular weight of sugars, i.e. monosaccharide sugars (glucose and fructose) and disaccharide sugar (maltose and sucrose). The data group of honey presented at area between the area of mono- and di-saccharide sugar because this sweetener composed of both types of sugars. The PCA results also showed that the input parameters from CuO modified sensor had the strongest influence on the first principle component.
The National Nanotechnology Centre under the Ministry of Science, Technology and Innovation Malaysia is embarking a 5-year project on benchmarking studies for risk assessment of nano-based products. Four major activities have been outlined. First activity will look into the distribution of nano-based products in the local market and the nanomaterials involved. Data will be used to develop an inventory list to be made publicly available. Second activity targeted for nanosafety studies will assess and recognize the gaps at local infrastructure and expertise. Third activity will be to identify the relevant testing and toxicology methods, and conduct some of the studies. Life cycle assessment studies will also be carried out on some of the nano-based products. Final activity will be to establish strategic collaboration with international and smart partners. The presentation will discuss the four activities above.
A good form of teaching and learning approach for nanosafety related topics is the mse of games and entertainment values activities. According to experts much of the way we learn today is through the use of higher order skills. Games naturally support the form of education that requires ability to think through and solve complex problems, or interact critically through language or media. Game playing is an excellent way to help wire our brains in ways that are crucial to the what, why, and how of learning needs for the 21st century.
How we learn from occupational diseases induced by exposure to conventional particles and how we prevent diseases from new materials by bridging the above with human studies and experimental studies? Many studies focus on specific effects of particles to obtain the knowledge on safe by design, but also we should understand non-specific effects of particles. The idea of mixed-dust pneumoconiosis (MDP) tells us the existence of commonality in the effects of different types of particles. The pneumoconiosis-inducing effects of dusts are known to depend on the content of the crystal silica in them. This idea gives a basis for occupational exposure limit by Japan Society for Occupational Health. The commonality of particles in induction of fibrosis can be described histopathologically by comparison with silicosis or asbestosis. Size, surface area or charge of the particles may influence these effects. A recent pilot study also generates a hypothesis of common effect of exposure to particles on autonomic nervous system in humans. Exposure to different-sized titanium dioxide and heart rate variability (HRV) was monitored in workers. The result showed that the number of particles with diameter less than 300 nm was associated negatively with HRV parameters of parasympathetic function, although the number of bigger particles did not show such associations with the HRV parameters. Understanding the non-specific effect of particles on lung and cardiovascular/autonomic nervous system might be useful for setting exposure limit of nanomaterials.
In the 50 years of the history of DFT proposed by Professor Walter Kohn in 1964, applying this formulation, a number of ab initio calculations have been performed to explain experimental observations and to predict new materials from atomic and electronic levels. Unfortunately, recent trend is to increse number of atoms to treat complex systems and to include parameters such as U for band-gap fitting or to modify Exc for van der Waals interaction, and shifting to phenomonology. By these methods, we can only explain experimental data, but not have good confidence to design new materials. In the talk, I will introduce several new methods which certifies our ab initio calculations with confidence; (1) initial atomic configurations desining with mathematicians based on symmetry consideration, (2) checking necessary conditions such as virial theorem and cusp condition, and (3) checking dynamical stability by phonon calculation.
After 5 years from the big tsunami attaked Tohoku area in Japan, still there remain a large amount of garvages. They have been collected to limited areas and classified as stones, steels, woods, etc., and among them there are a large amount of electronic circuit boards, which contain expensive metals should be reused. We have been trying to extract such metals by using ionic liquid experimentally and theoretically. The ionic liquid is functionalized by attached ligands for extraction of specific metal element, and is called “task specific ionic liquids (TSIL)”. Since the properties of TSIL varies strongly as a function of temperature and not easy to understand experimentally, especially temperature dependence of viscosity and hydrophobicity are difficult. We have developed a new theoretical method based on molecular dynamics and hydrodynamics to determine theoretically the viscosity in TSIL, and successfully applied to compute for several TSIL Up to the present Rh has been the worst to be extracted efficiently from garvage in industry. We studied the properties of Rh and proposed a new TSIL, which atomic structure is shown on the right and is expected to be suitable for Rh extraction compared to existing industrial methods.
The author is thankful to the Tohoku Innovation Materials Technology Initiatives for Reconstruction for the support of this research. He also is greatful to the HPCI project for the supply of supercomputer power as the grant ID hp150076, .
Global work in the Nanoscience & Nanotechnology (NS & NT) section is with great enthusiasm a nonstop challenge in methodology development for high-quality visualization and controlled manipulation of surface and/or bulk matter properties on the nanometre scale. Logical further exciting endeavour in the field is obviously clever utilization of developed skills in the defined delicate tasks for miniaturized device fabrication and advanced high-tech commercial product synthesis. Introduced in this plenary session will be recent and current research work of the Biochemistry-Electrochemistry Research Unit of Suranaree University of Technology that, in a broader sense, has a relation to the distinct frame setting of the NS & NT research. Covered with a general technical background introduction and presentation of own accomplishments will be:
• Graphitic STM probe tip (‘carbon nano-needle’) fabrication for in situ electrochemical scanning tunnelling microscopy (EC-STM) with widened assessable electrochemical potential window.
• Carbon nanotube (‘nano-conduit’) utilization in enzyme biosensors with a joint of high signalling molecule collection efficiency and long response stability.
• Disease marker biosensing with allosteric enzyme (‘nano-biocatalyst’) facilitation.
• Bacterial outer membrane protein channel (‘nano-biopore’) adaptation for efficient nutrient uptake under tough environmental conditions.
Worth mentioning that the enormous level of sophistication that with no doubt has been gained in areas such as scanning probe microscopy and (bio-) sensors through cumulative efforts of the many worldwide contributors is a clear demonstration of the capacity of human intelligence, talents and ambition for technology progress. Nevertheless, as evidenced, for instance, by the inherent perfection of metabolic enzymes, genetic DNA and membranous protein ion channels, the by far best current Nanotechnologist is Mother Nature and a lot can still be learned from an understanding and exploitation of life science nano-objects and processes.
Perovskite barium titanate (BaTiO3) BT-based ceramics have been of interest as one of the promising smart materials in commercial electrical components due to their non-toxic and variable electrical properties for several decades. However, these BT-based ceramics suffer from high sintering temperature requirement, low dielectric constant and high dielectric loss, causing a limitation for their practical utilizations, especially for the multilayer ceramic capacitors with ultrathin layers. Therefore, several approaches have been introduced to minimize these limitations including a method of reinforcing the ferroelectric matrix with high electrical conducting phases. Apart from their environmental friendly, gold nanoparticles (AuNPs) are thought to be reasonable candidate used for shortening the electrode distance (i.e. leading to stronger effective electric filed in the dielectric phase) in nanometal/BT ceramics. Hence, composites of BT and AuNPs phases are expected to synergistically combine the properties of both the ferroelectric BT and the conductive AuNPs, which could exhibit dielectric properties that are better than those of the monolithic BT ceramics. Here we demonstrate that under suitable sintering condition and AuNPs content, both densification and dielectric properties of the composites with fine-grained microstructure fabricated in this work were significantly improved, as compared to the monolithic BT ceramics.
Keywords: Barium titanate; Gold nanoparticles; Sintering
Colossal dielectric responses in rutile-TiO$_2$-based ceramics were investigated. Very high dielectric performance with ultra-high dielectric permittivity $(\varepsilon ^{\prime} \approx 10^{3} - 10^{6})$ and very low loss tangent $(\tan (\delta)<0.05)$ over wide frequency and temperature ranges were achieved by co-doping with M$^{3+}$ and N$^{5+}$ ions. Good temperature stability of $\varepsilon{\prime}$ was also obtained. Electron-pinned defect-dipoles, grain boundary response, surface-barrier layer and electrode effects have a great influence on the overall dielectric properties of rutile-TiO$_2$-based ceramics. X-ray photoelectron and Raman spectroscopy analyses were carried out to describe the origin(s) of the colossal permittivity. Impedance spectroscopy was used to study the electrical responses of the grains and grain boundary.
Gel electrolytes (GEs) are used in electrochemical devices replacing liquid electrolytes in order to avoid the evaporation of solvent and to increase the stability of devices. Many additives such as polymers, carbon fillers, and inorganic fillers have been used as a matrix in gel electrolytes to increase the viscosity and the ionic conductivity of gel electrolytes. In this work, silica nanoparticles were added to tertraalkyl ammonium based liquid electrolyte with propylene carbonate as a solvent to prepare GE. We selected N(Bu)4PF6 as a supporting solid electrolyte due to its stability at high temperature and under atmosphere as comparison to traditional lithium based electrolyte salt. Silica nanoparticles has been selected as a matrix due to its low cost and solidified properties in electrolytes. The conductivity measurements of GEs with varying nanoparticle contents were performed to determine the effectiveness of ion transport in the GE matrix. The conductivity of gel electrolyte was in a range of 1.0-6.0 mS/cm at room temperature. An operative potential window of the GE in contact with a Pt electrode were determined by cyclic voltammetry was -2.5 - +2.5 V vs. Ag(s). We also evaluated the diffusion coefficient of ferrocenium ions in prepared gel electrolyte to determine the effectiveness of gel electrolyte as a comparison to liquid electrolyte. The cyclic voltammograms of both gel and liquid electrolyte showed that the nanoparticles increased the viscosity of liquid electrolyte while maintained the effectiveness of ferrocenium ions transport in the prepared electrolytes. These novel gel electrolytes are a good candidate for electrochemical based gel electrolytes.
We report here the production of one-dimensional carbon nanomaterials (1D-CNMs) including carbon nanotubes (CNTs) and carbon nanofibers (CNFs) via the use of the oxidative dehydrogenation (C2H2-CO2) and the acetylene (C2H2) decomposition using a catalytic chemical vapor deposition (CCVD) method. Ni was selected as the catalyst for the synthesis due to its ability to produce different types of 1D-CNMs (CNFs and CNTs) by simple variation of the synthesis temperature. The successful synthesis was obtained via the currently used technique. CNFs were obtained at a relatively low temperature (400ºC) via both reactions whereas at relatively higher temperatures (>500ºC), CNTs were obtained. The electrocatalytic activity of the obtained products was investigated for oxygen reduction reaction (ORR), which is one of key reactions for the development of many technological devices including oxygen sensors, fuel cells and batteries. It was found that the carbon products exhibit good electrocatalytic activity (with the current density ranging from 1.22-5.04 mA/cm2), although they have not been incorporated with any metal catalyst and modified with any additional treatment. In addition, the products with different characteristics exhibit different catalytic behaviors. The insight obtained in this work is important for the development of non-metal electrocatalysts for ORR.
Al-doped ZnO (AZO) thin films were deposited on glass and silicon substrates by magnetron co-sputtering of two targets, a ZnO ceramic target and an Al metallic target. During the samples fabrication, ZnO was prepared by RF magnetron sputtering while Al pulses were added by DC magnetron sputtering with various shutter opening conditions. During the ZnO sputtering, the Al shutter was opened periodically with a fix duration time of 3 seconds. The amount of Al in the thin film was modulated by varying the number of Al pulses. In order to achieve the same film thickness for all samples, the total deposition time was then fixed. The properties of the AZO thin films were characterized by several techniques. From UV-Vis spectroscopy, all samples show more than 85% transmission in the visible range but reveal absorptions in the ultraviolet region, corresponding to the energy gap of ZnO. The results suggest an increase in the energy gap with higher Al concentration in the ZnO films. In addition, electrical properties of thin films were characterized by the Hall measurement. The film resistivity changes with Al pulsing. With increasing number of Al pulses, the film resistivity reduces and reaches the minimum at 105 pulses before bouncing up. The Al atomic concentrations in the films were also investigated by Auger electron spectroscopy. It was found that the Al atomic concentration at the minimum resistivity corresponds to 5.6%. Corresponding to the XRD results, they express the highest peak intensity of the 002 plane at the same Al pulsing condition. Such agreement of both techniques suggests a relationship between the electrical resistivity and the film crystallinity and grain size. Furthermore, the results suggest that the Al doping and oxide formation might be occurred at every pulsing condition. At Al pulsing below 105 times, the Al doping is more effective, however for Al pulsing above 105 times, the amount of Al in this region could be over the solubility limit of Al in ZnO. The aluminum oxide cluster which is the electrical insulator might form and take the dominant role for blocking the charge transport in thin film. The formation of insulating cluster might be confirmed by the slightly shifting of signal peaks from the X-ray photoelectron spectroscopy technique. This study could lead to the growth mechanism realization of transparent conductive oxide thin film to obtain the desired properties for optoelectronic devices application.
Recently there have been reports of room-temperature ferromagnetism induced in carbon compounds, including “Teflon” sheets and “Q-carbon”. In this work, we would like to create room-temperature ferromagnetism with the 1-cage from adamantane; the smallest member of the material called “diamondoid” series (nano-diamond structures). By using chemical vapor deposition (CVD), we prepared the films on various substrates, e.g. Si, quartz and sapphire. Intriguingly, we found the signature of moderately strong ferromagnetism with saturated magnetization up to 120 emu/cm$^{3}$. By using XPS and EDS, we have found no trace of any magnetic elements, e.g. Fe, Co, and Ni. The Raman spectra display forms of carbon bondings occurring in the film surface, including sp$^{2}$, sp$^{3}$ and C-H. Furthermore, NMR spectra show that chemical bonding of the substrate have changed during the CVD process. These suggest that carbon atoms of adamantane molecules are largely decomposed to other forms with non-sp$^{3}$ bondings. The origin of this ferromagnetism, including dangling bond (which is suggested to be the cause of ferromagnetism in Teflon sheets) and a single π-state coupling (which is reported to be cause of ferromagnetism in isolated hydrogen atom absorbed on graphene), will be discussed.
Materials Science and Engineering Program, and Nanoscience and Nanotechnology Center, Faculty of Science, Mahidol University, Rama VI Road, Phyathai, Bangkok 10400
Honeycomb sheet, graphene like, structure has been interested and the planar structures of silicon carbide (SiC), boron phosphide (BP) and mixed of both materials h-(SiC)1-x(BP)x were investigated with x values of 0.00, 0.25, 0.50, 0.75 and 1.00. The 2 atoms per unit cell of hexagonal and 4, 8 and 16 atoms per unit cell of orthorhombic configurations were used in atomic structure calculation with 1.5 nm space distance between layers of graphene like structure. The calculation is set for 500 eV energy cutoff, using local density approximation (LDA) exchange-correlation functional, 200 Ry mesh cutoff. The lattice constant was varied to evaluate the stable atomic structures together with the bond lenght. Then, the band structures including energy band gap, used to determine electronic property, was calculated to guide the utilization of novel electronic device for new millennium.
Nowadays, environmental problems, for example, climate changes, overpopulation, and emerging and re-emerging diseases are considered as the global issues obstructing the human activities. In fact, environmental healthrelated problems are derived from several microbialforwhich an accurate and early detection and separation is a way to prevent the spread over. Therefore, specific sensors and/or effective extraction to detect the types of microbial are important. On this viewpoint, polymeric nanomaterials can be developed to obtain the materials as desired. For the past decades, our group focuses on functionalization of chitosan in water-based system for biomedical purposes. Here, we consider chitosan-metal nanoparticles so that the materials obtained are satisfied for microbial detections and extraction. The presentation covers the preparation of chitosan hybridized with metal nanoparticles,i.e. magnetic and gold nanoparticles, including the model studies on bacteria and fungi detection/extraction. The presentation also extends to the system in which we can entrap-release metal nanoparticles to isolate the metal nanoparticles which was hybridized with chitosan after use.Based on this concept, we demonstrate the way to fabricate the naturally abundant biomaterial, i.e. chitosan to be nano-biosensors which are simple, effective and practical for environmental health’s purposes.
Although manganese oxide and graphene supercapacitors have been widely studied, their charge storage mechanisms are not yet clear. In this work, we have investigated the charge storage mechanisms of MnO2 nanosheets and N-doped reduced graphene oxide aerogel (N-rGOae) using in situ X-ray absorption spectroscopy (XAS) and electrochemical quartz crystal microbalance (EQCM). The in situ XAS carried out together with a chronoamperometry indicates that the oxidation state of manganese in the MnO2 electrode being charged increases from +3.01 at 0.0 V vs. SCE to +3.12 at +0.8 V vs. SCE and then returns to +3.01 for the discharge process. This is an origin why the MnO2 nanosheets can provide excellent capacity retention. The mass changes of the N-rGOae and MnO2-coated Au/TiO2 quartz crystal EQCM electrodes during the charge process gradually increases to 8.15 μg cm-2 and 10.34 μg cm-2, respectively. A finely tuned mass ratio of MnO2 to N-rGOae is 1.75 providing the maximum charge storage performance. A single coin-cell asymmetric supercapacitor (CR2016) of MnO2//N-rGOae provides a maximum specific capacitance of ca. 467 F g-1 at 1 A g-1, a maximum specific power of 39 kW kg-1 and a specific energy of 40 Wh kg-1 with a wide working potential of 1.6 V at 93.2% capacity retention after 7,500 cycles. The coin-cell supercapacitor can practically supply electricity to a spinning motor with a nominal voltage of 3 V for 1.45 min. The enhancement in the specific energy and specific power of the MnO2//N-rGOae supercapacitors can compete with the batteries in many applications.
KEYWORDS
Charge storage mechanism; Asymmetric supercapacitors; Birnessite-type potassium manganese oxide; N-doped graphene aerogel; In situ X-ray absorption spectroscopy
Conformational dynamics of proteins have been suggested to play crucial roles in protein-protein binding and dissociation which are the two fundamental steps of protein–protein interactions, and determine the binding affinity. Intrinsic disorder in specific protein regions plays its role in recognition and such disordered protein regions may control the degree of motion between domains and in fact confer advantages over folded proteins in binding. Not surprisingly, a major endeavor in recent years has been to develop models and methods for simulating the dynamics of proteins, and relating the observed behavior to experimental data. Here, we demonstrate how protein dynamics dictate the binding affinity through the atomistic molecular dynamics simulations (MDs) and Gaussian Network Model (GNM), an elastic network model introduced at the amino acid residue level. A study cases for HIV and Dengue will be discussed. Comparison of both methods will be discussed. Binding free energy from longtime-scale molecular dynamics simulation under graphic processing units (GPUs) computing and mode shape analysis from GNM can be used to distinguish the higher/lower affinity protein towards the protein target.
Manganese cobalt spinel oxide (MnCo2O4) nanofibers were fabricated by electrospinning technique using polyacrylonitrile (PAN) as a polymer source and Mn and Co nitrates as metal sources. TGA-DSC was used to study the thermal property of the as-spun. The as-spun and calcined MnCo2O4 samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). After calcination of the as-spun MnCo2O4 nanofibers (fiber size of 986±12 nm in diameter) at 700, 800, and 900 °C in air for 3h, the MnCo2O4 nanofibers with spinel structure were successfully obtained. The MnCo2O4 nanofibers have fiber size of 274±8, 254±8, and 239±7 nm in diameter for the sample calcined at 700, 800, and 900 °C, respectively. The electrochemical performance was investigated by using a three-electrode cell system in 6.0 M KOH. The results show that the specific capacitance was determined to be 44.30, 31.79, and 25.27 F/g at a scan rate of 2 mV/s, and 66.78, 57.12, and 51.12 F/g at a current density of 1.0 A/g for the samples calcined at 700, 800, and 900 °C, respectively. The best capacitance retention over 70% after 1000 cycles was observed for an electrode prepared from 700°C-calcined MnCo2O4, indicating its long term cycling stability.
In this work, we report the electrochemical properties of the KFeO2 nanoparticles synthesized by a sol-gel method. The synthesized KFeO2 nanoparticles were calcined in air at the different temperatures from 500 to 800ºC for 2 h. The X-ray diffraction (XRD) pattern confirms the phase formation of KFeO2 with the average crystallite sizes ranging of 20-50 nm. With increasing calcination temperature, the crystallite size of the calcined samples decreased. SEM and TEM images revealed the calcination temperature affect to the morphology of the calcined samples, causing the formation of nanoparticles different in sizes. Moreover, the formation of KFeO2 phase of the calcined samples was also confirmed by energy dispersive spectroscopy (EDS) and selected area electron diffraction (SAED) techniques. The electrochemical performances were studied by cyclic voltammetry (CV), galvanostatic charge/discharge (G-CD), and electrochemical impedance spectroscopy (EIS). The CV results show that the highest specific capacitance (CS) was calculated to be 175.03 F/g at scan rate of 2mV/s in the sample calcined at 700ºC. For the G-CD results, the highest CS was determined to be 263.18 F/g at current density of 1A/g in the sample calcined at 800ºC. Ragone plots of power density versus energy density show that the calcined samples are supercapacitors. In addition, the EIS analysis of the results is also discussed.
Activated biomass carbon from coconut shell was composited with FeOx and MnOx by hydrothermal method at 160 oC for 18 h. The phase structure, morphology and chemical composition of samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy dispersive X-ray spectroscopy (EDX). The electrochemical properties of samples were studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) technique in a three-electrode electrochemical cell with 6 M of KOH electrolyte solution at different scan rates (2-200 mV/s) and constant current densities (1-30 A/g), respectively. The activated biomass composite with FeOx show the highest specific capacitances of 141.8 F/g at 2 mV/s scan rate while the activated biomass composite with FeOx and MnOx show the highest specific capacitances of 146.3 F/g at 1 A/g current density. These results show that the specific capacitances of activated biomass electrode can be improved by composite with FeOx and MnOx. Moreover, all samples also exhibit charge-discharge reversibility efficiency more than 87% after 500 cycles.
Dye-sensitized solar cells (DSSCs) are a leading contender for low-cost solar energy generation. The highest efficiency of DSSC is from platinum(Pt) counter electrode (14.1%), however platinum is very expensive and there are other materials that can use as counter electrode such as conductive polymer, carbon nanotube and other carbon form. In this work we use diamondoids (nano powder of diamond) which exhibit negative electron affinity property, enabling the better transfer of electrons back to DSSC. We prepared counter electrodes by using diamondoids with –thiol function and applying the self-assembly monolayer technique on gold and platinum substrate. We fabricated working electrodes by using TiO2 coated on FTO glass and immersing it in N719 dye. For electrolyte we used iodine electrolyte as media collector. The efficiency of the DSSC with adamantane (smallest molecule of diamondoids) film is close to one with the reference cell Pt film. The large enhancement comes from the DSSCs with tetramantane films which give efficiency as high as 10.95%, comparing to the reference Pt cell with efficiency of 8.55%; this increase is approximately 25%. However, we still have some problem with this technique. Iodine electrolyte destroys the gold substrates and shortens the cell lifetime greatly. Then we try to deposit diamondoids films on platinum substrate and found that diamondoids can enhance efficiency of platinum slightly with very high stability as platinum. Irrespective of the exact microscopic mechanism driving this, our results already reveal exciting, but hitherto unappreciated, possibilities for the use of diamondoids in dye-sensitized solar cells. We expect our findings to be of relevance to perovskite-based solar cells. More generally, our approach offers an attractive and low-cost route to exploit diamondoids in a range of applications in other catalytic processes.
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We have designed a complete-antibody-like construct where the CL and CH1 domains of trastuzumab are exchanged for a pair of CH3 domains and efficient heterodimerization of the light and the heavy chain is achieved using “Knobs-into-Holes” strategy. The construct prepared in this way expressed at a high level in HEK293 system. Rational mutagenesis of the amino acid residues located at the interface between the variable domains and the exchanged CH3 domains was applied to significantly improve thermostability and solubility of the molecule. The domain-exchanged construct was able to bind to the surface of the strongly HER2/neu positive cell line SK-BR3 within less than 2-fold the affinity of trastuzumab, but could nevertheless incite a more potent T-cell activation in an ADCC assay. This could be explained by a more than 3-fold stronger binding to the FcRIIIa. The domain-exchanged antibody presents a novel class of engineered immunoglobulin molecules of therapeutic interest due to their potentiated engagement of the molecules that can elicit effector functions.
SHuffle is a genetically engineered E.coli strain that allows disulfide bond formation in its cytoplasm with high fidelity. Many proteins containing disulfide bonds have been successfully expressed in SHuffle. In this study, we have expressed for the first time full length human, rabbit and mouse antibodies, along with chimeric versions, including the commercial blockbuster Humira in SHuffle (Nature Communications (2015) Aug 27; 6:8072). In order to improve the folding and assembly of IgG, we have co-expressed a set of chaperones and other helper proteins from our newly developed pAL plasmid system. The co-expression of the pAL plasmid set increased the production of IgG in SHuffle several fold. The IgG produced in SHuffle was comparable to hybridoma produced IgG. SHuffle is an easy, fast, robust platform for antibody engineering, screening and expression.
To be added
Nanomaterials have received unceasingly consideration for decades. Profuse utilizations have been afforded to raise the efficacy of research in numerous scientific fields since their discovery. This novel supplies trigger the versatility of materials properties in which diversely expedite the applications in analytical research. Due to exceptional features derived from indigenous of particles in nanometer-size, they have received abounding attraction in environmental, food, clinical analysis. Particularly, medical detection based on nanomaterials as signal amplification has been positively subjected as crucial keys towards conceptual biomedical analytical tools because nanomaterials process biocompatible property. For these reasons, many research groups have proposed various strategies engaging nanomaterials for detection of biological targets. Our group also resembles an interest of nanomaterials use and characteristic. However, we exclusively highlight the reinforcement of excellent properties of graphene in electrochemical detection, also nanoparticles as probe for optical detection.
The outstanding physical, chemical, and electrical features compel an adaptation of graphene (G) in many means of electrode modification. Its magnificent electrons conductivity arises from layer of carbon atoms packed closely into a two-dimensional honeycomb arrangement. Consequently, our groups have adopted graphene in numerous clinical sensing applications including cholesterol and glucose. In our works, graphene was consolidated with polyaniline (PANI), a conducting polymer, on the electrodes. The integrity of geminate materials improved the sensitivity in electrochemical detection substantially. Following a thorough investigation of electrochemical properties, the composite nanomaterials were electro-sprayed onto screen-printed carbon electrode (SPCE) and applied for cholesterol detection. The results demonstrated clearly that the signal was improved and more-well defined. The limit of detection proposed in this work was as low as 1 μM after optimization. Another work has confirmed the advantages of G-PANI by casting the working electrode in the electrochemical compact disk (eCD) platform prior detection of glucose. Wide linear dynamic range (1-10 mM) was obtained with low detection limit of 0.29 mM. Both methods were applied in real serum and blood samples showed satisfied results validating with the standard methods. In addition, recently our groups have reported methodology for detection of human papillomavirus (HPV) using SPCE surface modified with G-PANI. The signal was distinctly increased as a great function of G-PANI, while the selectivity was achieved from the PNA probe.
Nanoparticles are particles in nanometers range which dominate the extra unique properties contrasting from their bulk materials. Numerous prestige is inscribed for optical features of nanoparticles. Therefore, applications based on colorimetry and spectrophotometry of nanoparticles are extensively introduced. Our groups also developed a superior methodology for detection of metal ions in blood samples on facile and cheap paper-based analytical devices (PADs). The etching reaction between silver nanoplates (AgNPls) and metal target was attributed to the resulting color change. From pink to colorless, the detection of copper ions (Cu2+) was successfully achieved. On the other hands, nanoparticles occupied high surface area to volume ratio which benefits the electrons transferring among surface of conducting materials. A comprehension of this behavior accomplished our skilled electrochemical works on enzymatic cholesterol detection using silver nanoparticles (AgNPs) electroplating incorporating with cholesterol oxidase (ChOx) on boron doped diamond (BDD) electrode. The enhancement of H2O2 signal was obtained from AgNPs depositing on the surface of working electrode, whereas ChOx provided the selectivity for this reaction. In this works, not only the sensitivity was increased, but the cathodic peak also displayed more well-defined compared with bare electrode. This work demonstrated that cholesterol as low as 0.25 mg dL-1 can be detected in real serum samples with the involvement of AgNPs.
Keywords: Graphene, Nanoparticles, Electrochemical detection, Optical detection, Paper-based analytical devices (PADs)
Selective Permeability of Antimicrobial Agents through the Protein Nanopore of the Highly-Drug Resistant Melioidosis Bacterium Burkholderia pseudomallei
Anuwat Aunkhum, 2 and Wipa Suginta*1 ,2
1Biochemistry-Electrochemistry Research Unit, Suranaree University of Technology, Nakhon Ratchasima, Thailand
2School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
Tel: +66-44226187; E-mail: wipa@sut.ac.th
BpsOmp38 is a trimeric β-barrel protein abundantly located on the outer membrane of the ultra-drug resistant Melioidosis bacterium Burkholderia pseudomallei. Each barrel of BpsOmp38 has a diameter of about 1.2 to 1.5 nm and contains 16 β-strands connected with each other in an antiparallel fashion. This biological nanopore acts a molecular entry, allowing small, hydrophilic molecules, such as monosaccharides, amino acids, and antimicrobial agents, to pass through the bacterial membranes by passive diffusion. In our study, we determined the rates of sugar permeation, using liposome swelling assays and found that the permeability rates decreased as the molecular sizes of sugar increased. The permeation rates of the selected neutral sugars were in the order: L-arabinose (Mr 150) > D-galactose = D-glucose = D-mannose (Mr 180 ) > D-GlcNAc (Mr 221) > D-sucrose (Mr 342). Slight permeation of D-melezitose (Mr 522) or D-raffinose (Mr 504) was observed, suggesting the size exclusion limit of the molecules to pas through the BpsOmp38 nanopores to be < 500 kDa. The permeability of antimicrobial agents through the BpsOmp38 channel was further investigated and found to be barely correlated with molecular sizes, since most antimicrobial compounds carried net charge(s) that affected their relative mobility. For example, ceftazidime and cefoxitin with a net charge of -1 showed significantly higher permeating rates than the rates for meropenem and imipenem with a net charge of 0. The results emphasized the importance of ionizable groups lying inside the pore interior in controlling the molecular passage of BspOmp38. The data provide an implication for the strategic drug design that may help to improve the susceptibility of this highly drug resistant pathogen towards new drug molecules.
Keywords: Biological nanopore, outer membrane protein; melioidosis, antimicrobial resistance, Burkholderia pseudomallei
Supported by Suranaree University of Technology and the Thailand Research Fund.
Here we developed a fluorescent probe for in vivo colorectal cancer detection using Cy5-doped silica nanoparticles (Cy5-SiNPs) conjugated to monoclonal antibody (mAb) with controlled orientation. Monoclonal antibody specific to anti-epithelial cell adhesion molecule (EpCAM), a cell surface protein overexpressed in colorectal carcinoma, was conjugated on the Cy5-SiNPs coated with protein G layer. The site specific interaction between protein G and constant domains (Fc) of the antibody allowed for oriented immobilization of the antibody with binding sites (Fab) facing outward. As a result, the target binding affinity of the antibodies is maintained. The targeting efficiency of the Cy5-SiNPs with oriented mAb conjugation demonstrated 8 times higher sensitivity than Cy5-SiNPs with randomly conjugated mAb for in vitro detection of HT-29 cells using confocal fluorescence imaging and flow cytometry. In vivo targeting efficiency of the Cy5-SiNPs with oriented mAb conjugation was further investigated on HT-29 tumor xenograft model. Fluorescent signal was only observed at the tumor site of the mouse injected with Cy5-SiNPs with oriented conjugation of anti-EpCAM mAb and the fluorescent signal remained up to 14 days post injection. Whereas the mouse injected with control probe demonstrated weak fluorescent signal at all timepoints. In conclusion, this study demonstrated that the Cy5-SiNPs with oriented antibody conjugation has enhanced tumor targeting efficiency in vitro, and is applicable for targeted in vivo imaging. This make them a promising candidate to be developed into a new class of effective fluorescence contrast agents for cancer diagnostics.
Material surface properties are considered as critical factor for the study of in Vitro cell growth pattern and activities. It provides advantages not only for study of cellular activity but also for biomedical technology such as tissue engineering. Neuron is a typical cell type widely used to examine cell communication, alignment and differentiations. In the present study, a simple pattern of indium tin oxide (ITO) for neuron culture is introduced. Circular inter-digitated design of ITO electrode was fabricated to capture a small amount of cell for cellular observations. In order to enhance cell attachment, the fabricated electrode surface was modified by poly-L-lysine, a type of extracellular matrix. SH-SY5Y cell, a human neuroblastoma cell line, was cultured on the modified surface and the cell growth was observed periodically. Small electrical field was applied to the culture for a period of time then cells were fixed for SEM imaging. It is clearly demonstrated that the amount of differentiated cell increased from 42% to 63.5% after subjected to small electric field. In addition, the possibility of fabricated nanostructure electrode can indicate the potential utilize as a single cellular activities without cell invasion.
Keywords: Neuron, SH-SY5Y, cell differentiation, ITO electrode, electrical effect
Abstract
Self-healing materials are a class of materials that can repair themselves. This feature is very interesting because it allows for saving resources to build new materials, saving energy need to make new materials, and finally reducing the amount of waste that can contaminate the environment.
In our research, we use the power of nanotechnology to tailor new materials that are useful for self-healing and anticorrosion properties. We show here different methods for encapsulating healing agents and corrosion inhibitors. The release of the healing agents is either trigger by mechanical damage of the capsules or triggered by the corrosion of metal. In another approach, we embedded nanocapsules in nanofibers by colloid-electrospinning. The release profile of payloads encapsulated in the nanocapsules could be controlled by the materials constituting the nanocapsules shells and the nanofibers matrix.
Keywords: Anticorrosion, Colloid-electrospinning, Nanocapsules, Nanofibers, Self-Healing Materials
References
[1] Zhao, Y.; Fickert, J.; Landfester, K.; Crespy, D. Small 2012, 8, 2954
[2] Fickert, J.; Landfester, K.; Crespy, D. Polym. Chem. 2016, 7, 4330
[3] Tran, T.H.; Vimalanandan, A.; Genchev, G.; Fickert, J.; Landfester, K.; Crespy, D.; Rohwerder, M. Adv. Mater. 2015, 27, 3825
[4] Lv, L.-P.; Zhao, Y.; Vilbrandt, N.; Gallei, M.; Vimalanandan, A.; Rohwerder, M.; Landfester, K.; Crespy, D. J. Amer. Chem. Soc. 2013, 135, 14198
[5] Vimalanandan, A.; Lv, L.-P.; Tran, T.H.; Landfester, K.; Crespy, D.; Rohwerder, M. Adv. Mater. 2013, 25, 6980
Generally, Organic LEDs can be fabricated using either vacuum deposition or wet processes. It is well known that vacuum deposition can produce high efficiency Organic LEDs. Solution processable organic light emitting diode offers simpler, cheaper method of fabrication which is compatible with the roll-to-roll and inkjeting process. However, generally solution processable LED suffers from poorer efficiency and the generally lack of materials in the market. Here, we demonstrate that by simple surface engineering, the efficiency of commercial available long lifetime ‘super-yellow’ poly-(p-phenylenevinylene) (SY-PPV) can be almost doubled. In order to obtain high efficiency solution processable Organic LEDs, molecules of size larger than 1000 molecular weight with triplet energy higher than 2.8eV are required. Hence, we have developed an accurate computational method to predict the triplet energies of materials allowing us to screen a wide range of materials. From here, we are able to synthesize materials with high triplet energies. We also found out that intermolecular distance and non-chromophoric side group substitutions such as bulky alky groups and fluorine can significantly influence the triplet energy. Effective charge confinement is also important to obtain charge balance for high efficiency Organic LEDs. Here we also demonstrated fully solution processable red, green blue organic phosphorescent light emitting diodes with little deviation of CIE colour coordinate within a wide range of brightness as a result of effective excitons and charge confinement.
To be added
Self-assembly nanoparticle films from convective deposition using assistance of vibrated substrate can show optical diffraction in reflected mode, due to uniform high order surface structure. In this work, we investigated the optical diffraction from binary-nanoparticle films which were coated by two types of nanoparticle with different diameter i.e. 100 and 1000 nm of polystyrene and silicon dioxide nanoparticle, respectively. The mixed suspension was prepared by 7 and 20% of polystyrene and silicon dioxide nanoparticles, respectively. The assembled films from binary nanoparticles were deposited with horizontal vibration frequency of 40-60 Hz and at room temperature. The first and second orders of light reflection from film’s surface can be observed by detecting light wavelength from various angles of reflection at each incident angle. The films coated with two sizes of particle had the shift of an diffraction angle. This is due to nanoparticles are assemble among the microparticles then the closed packing is differ from the monosize nanoparticle deposition. The angles of reflection from binary sizes were larger than those of single-size coating.
Multiferroic materials, which exhibit both electrical and magnetic ferroic orders, have attracted much attention due to its potential application in electronics. Normally, the relation of both phenomena have to be analysed by several instruments. Here, optical-Kerr-effect properties of bismuth ferrite (100) thin film has been investigated. The Kerr rotation of light reflected from the BiFeO$_3$ surface was measured through reading from the photodiode while the magnetic field and electric field was applied. Our results shows the electrical-polarization and magnetization of films. Moreover, an ultraviolet-induced enhancement of polarization can be detected, imply magneto and electro-optical measurement may be a powerful method in multiferroic materials research.
Nanoparticles-based drug/gene delivery have been reported for potential therapeutic management of various ocular surface and corneal disorders [Kompella UB, et al., Nanomedicines for back of the eye drug delivery, gene delivery, and imaging. Prog Retin Eye Res. 2013;36:172-98]. In this study, we have examined penetration of mono-dispersed silica nanoparticles stained with Rhodamine B (RhB) and FITC at the microscopic level. Specifically, we have employed a custom-built confocal scanning microfluorometer (CSMF).
Our custom-built CSMF is designed for recording depth-resolved fluorescence across the cornea repeatedly over long periods (several hours) [Srinivas SP, Maurice DM., A microfluorometer for measuring diffusion of fluorophores across the cornea. IEEE Trans Biomed Eng. 1992 Dec;39(12):1283-91]. Depth resolution of the CSMF is ~ 7 µm using a 40x water immersion objective of 1.2 mm working distance; Zeiss) at 2.66 µM of fluorescein. Excitation, obtained from blue/green LEDs, is < 2 µW at the focal plane. This limits the potential for photobleaching. Scanning speed > 40 µm/sec. Simultaneous trans-corneal fluorescence and scatter can be accomplished.
Mono-dispersed silica of 6 nm (Sigma Inc; Cat # S5130) were stained with RhB (Sigma Inc; Cat #83690) by overnight exposure of the nanoparticles to 0.1 mg/mL of the dye. The particles were washed in PBS 2-3x and then used next day. Excitation from a blue LED was filtered through an interference filter (470 + 10 nm). RhB fluorescence ( > 530 nm) and scattered light collected through the exit slit, which is held parfocal to excitation slit, were detected by the PMTs (Fig. 1). Experiments were performed with excised porcine eye. As a lipophilic dye, RhB partitions into epithelium and accumulates over time and eventually diffuses into stroma as observed. We found significant uptake of the nanoparticiles into the epithelium. But lack of significant fluorescence at anterior stroma following FITC-stained nanoparticles (Fig. 3C) indicates that although the nanoparticles are taken up by the epithelium, not much is released into the stroma. When RhB-Si or FITC stained chitosan-dextran sulphate (CDNs; 400 nm) nanosuspension were administered on bare stroma, the particles penetrated significantly.
Our data is insufficient to explain the penetration of the Si nanoparticles across the cornea with and without epithelium. The collagen fibrils in the stroma, which lie in the lamellae and are parallel to the surface of the tissue, can be expected to offer steric hindrance to the movement of the particles in conjunction with the charged glycosaminoglycans surrounding each fibril. Moreover, we recall that the fibrils in a given lamella are parallel to one another with each lamella oriented at a finite angle with respect to the neighboring lamellae. How this intricate ultrastructure permits movement of nanoparticles (6-50 nm), with and without an inwardly-directed water movement, remains to be explored.
Carbon nanotube (CNT) has an excellent property in high electrical conductivity and can be mixed with an active compound in order to use as a functional electrode. Due to variety of metal phthalcyanine (MPc) compound can be formed by different metal atom, the MPc with several metal spices was used as an array detection in electronic tongue classification for a number of coffee types. In this work, 100 mg of CNT and 100 mg of MPc including CoPc, FePc, ZnPc, and MnPc powders blended with 700μl of paraffin oil were used as working electrodes by embedding in a hollow Teflon rod. Electrochemical characteristics of the fabricated electrodes in Robusta, Arabica, blend coffee and cocoa were investigated by scanning cyclic voltammogram (CV) with scanning rate of 0.05V/s from -1.5 to 1.5V respectively to Ag/AgCl electrode for five scanning loops. The CV of blended CNT with some MPc indicated the effect of catalytic oxidation of saccharides and/or polyphenol on the sensor surface. This leaded to distingue pattern of CV for successful classification in these four groups. The obtained main feature of electrochemical information was analyzed by using wavelet analysis and then the principal components analysis (PCA) was implemented to represent the distribution in the first few principle components. The PCA results indicated separate groups with total contribution more than 90% representing from the PC1 and PC2 and the major feature extraction can be described by components of wavelet analysis.
A ‘consume within’ indicator is important for the perishable foods because the oxygen is the growth factor of aerobic microorganisms in perishable foods. It follows that a useful addition in intelligent packaging technology is a capable diagnostic indicator which allows the real-time monitor of the quality or safety of the foods. A novel UVA-activated, ‘consume within’ indicator ink is based on TiO2 as a nano-semiconductor photocatalyst. An anatase TiO2 is encapsulated in CWI-ink containing remazol brilliant blue r, glycerol and hydroxyl ethyl cellulose. This study focused on characteristics of UVA-activated, CWI-ink, which utilized a nanocrystalline, TiO2, to activate the indicator. This novel CWI-ink was applied as a thin film on a glass cover slip. The dried-ink film, originally blue color was photoactivated to yellow by UVA-light under oxygen-free condition, and recovered to its original color when exposed to the oxygen. The result indicates that the uncovered (i.e. no O2 barrier) and covered RBBR indicator may find a role as consume-within indicators for fresh food at 5°C (where consume-within lifetimes of 24/48 h are of relevance for fresh foods like meat and seafood).
Keywords: Anthraquinone, ‘Consume within’ indicator, Intelligent packaging, Oxygen indicator, Semiconductor
Pomegranate extracts have been reported as biologically active having desirable properties such as antioxidant, antifungal, anticarcinogenic and anti-inflammatory capabilities. Anthocyanins found in pomegranate fruit have higher antioxidant activity than vitamin-E (α-topcopherol), β-carotene, and ascorbic acid. Although, it shows good biological activity against a variety of target, it easily decomposes and has high acidity (pH 2.90-3.75), which is not appropriate for topical treatment on human skin (pH 3.5-5.5). It is very important to improve the properties of the pomegranate extracts to obtain desirable characteristics and properties appropriate for skin treatment. In this work, the pomegranate extracts have been encapsulated in a particle, called “liponiosome”. The liponiosome is composed of phospholipids, which are the main components in liposomes, and non-ionic surfactants, which are the main components in niosomes. The combination of these encapsulation substances, liposomes and niosomes, is referred to as “liponiosome”. This encapsulation technique provides desirable properties in terms of particles sizes (~100 nm), stability (at various conditions such as at 4˚C, room temperature and 40˚C for 1 month and during a heating-cooling cycle for 6 cycles) and efficacy. Moreover, this process is cheap, provides a non-toxic product and is biocompatible with the human skin.
Lead-free xBaZrO3-(0.85-x)BaTiO3-0.15CaTiO3; x = 0.00-0.20 (xBZ) ceramics were successfully prepared using the conventional solid-state reaction method. X-ray diffraction data showed a pure-phase perovskite structure for compositions up to x < 0.200. At room temperature, x-ray diffraction patterns of ceramics with the composition range of 0.00 ≤ x < 0.10 possess tetragonal structure. Mixed-phase coexistence of tetragonal and rhombohedral phases were found at 0.10 ≤ x ≤ 0.15 and transformed to cubic for x > 0.125 according to the lowered Curie temperature. Raman scattering showed mixed phases of tetragonal and orthorhombic phases. Temperature-dependent dielectric data shows anomaly phase transitions determined by composition changes. Phase diagram was provided according to temperature-dependent dielectric data. Compositions near composition-induced phase transition provided enhanced ferroelectric and piezoelectric properties. Unipolar electric field induced strain of x = 0.125 ceramic shows surprisingly high longitudinal piezoelectric coefficient (d33*) of 2244 pm/V at relatively low electric field of 5 kV/cm. Fatigue measurement carried out on the morphotropic phase boundary composition showed a small degradation in maximum strain after 106 cycles using an applied field of 20 kV/cm at 10 Hz.
This study was aimed to determine the effect of methane gas concentration on the voltage response of tin oxide (SnO) film. The sensing circuit of the tin oxide film was interfaced to a laptop computer throug an arduino microcontroller for data acquisition. Real time data table and graph can be visualized on the laptop screen during the gas sensing process.
The sensor was enclosed in an airtight plastic jar container connected to a gas source and a water trap that maintained atmospheric pressure in the chamber. A mixture of 1% methane in helium was introduced into the chamber at a rate of 2 liters per minute (LPM) using a mass flow controller. The gas mixture was introduced intermittently at several stages. Each stage was followed by a standby stage during which there was no gas flow and the sensor was allowed to equilibrate with the gas mixture. It was observed that during the introduction of gas at each stage the voltage output of the sensor was increasing. During the standby stage there was no observed change in the voltage output as indicated by a flat response in the graph of voltage output versus time. The added quantity of gas can be computed from the flow rate and time duration of each stage. The incremental concentration of gas was also computed after each succeeding stage.
The computed concentration in parts per million (ppm) was plotted with the measured voltage output per stage. Results showed a linear relationship between gas concentration and voltage output in the range of 3.75 to 7.8 ppm with a linearity of 0.99 and sensor sensitivity of 140 mV/1000 ppm. The sensitivity and linearity were 161 mV/1000 ppm and 0.98, respectively in the range 1000 to 9000 ppm. It is recommended to conduct more trials at different concentration ranges, different methane input mixture percentages, and different flow rates.
Keywords: tin oxide, sensor, methane, gas concentration, gas response, sensitivity
The wetting property of materials continues to be studied due to its important applications in many natural and industrial processes. Applying an external voltage affects the contact angle and offers a way to manipulate wettability without changing the chemical composition of the contacting phases. The use of external electric fields to control wettability has promising new applications in microfluidics which include laboratory-on-a-chip platforms for various biological sample preparation and analysis processes, fluid lens systems, electrowetting displays, and control of fluids in multichannel structures. Among various droplet manipulating mechanisms, electrowetting-on-dielectric (EWOD) is widely used because of its relatively simple device structure and fabrication. In this study, we investigate enhanced wetting effects of metal nanoparticles at very low concentrations in fluids in an electrowetting on dielectric (EWOD) experiment.
Nanoparticles manifest completely different properties (physical, chemical, electronic, magnetic and optical) from their bulk material. We explore the interaction of gold nanoparticle (AuNP) suspensions in a liquid droplet with applied electric field which cannot be observed with bulk gold. A basic planar electrowetting set-up is employed consisting of a bottom copper electrode coated with a thin insulating layer of uncured PDMS (Silicon oil) mounted on an adjustable stage and a platinum wire upper electrode injected in contact with the sessile electrowetting gold nanofluid microdroplet sitting over the dielectric layer. A voltage source is connected across the top and bottom electrodes and changes in the contact angle of the droplet, as voltage is varied, is captured using a USB microscope camera. The contact angles of the images are determined using a free software Image J.
We first tested our experimental set up with pure fluid (deionized water) microdroplets as the reference fluid. We found the uncured PDMS (Silicon oil) dielectric layer to have high hydrophobicity where the sessile water droplet is observed to have an average initial contact angle of 102.6 degrees (no applied voltage). As voltage is applied at increasing increments of 1 volt, we observe electrowetting actuation (decrease in contact angle). The data for electrowetting of the reference fluid fits well with the Young-Lippmann equation for EWOD with an effective dielectric constant of about 18 and a saturation or breakdown voltage of 35V corresponding to decrease in contact angle to 67.2 degrees. Very low concentrations of gold nanofluid (deionized water containing gold nanoparticles with an average size of 10 nm) were prepared with the following concentrations (µM) : 0.5, 0.25 and 0.05. Following the same procedure with the reference fluid microdroplets, we found that the presence of nanoparticles enhanced the electrowetting actuation of the sessile microdroplets in the described EWOD configuration. All concentrations containing gold nanoparticles showed enhanced electrowetting response (greater decrease in contact angle as voltage is increased) compared to the reference fluid (deionized water). The higher concentration, the more sensitive the electrowetting response. The 0.5 µM gold nanofluid concentration showed sensitivity to very low applied voltage (0-10V) with voltage breakdown (Vx) at 10V corresponding to a saturation contact angle (θx) of 68 degrees and a corresponding effective dielectric constant of 160. The 0.25 µM gold nanofluid concentration showed voltage breakdown Vx =20V, θx = 64.5 degrees and k = 50 while for the 0.05µM gold nanofluid concentration, Vx =30V, θx = 59.5 degrees and k = 30.
Finally, to further verify that the gold nanoparticles are really the reason for the enhanced electrowetting actuation in the microdroplets, an ultra low concentration (0.005 µM) of the gold nanofluid is prepared. The ultra low gold nanoparticle concentration showed identical response to the electrowetting of the reference fluid verifying our claim of the enhanced electrowetting effect due to the gold nanoparticles. These results with sessile microdroplets in EWOD may pave the way to introducing metal nanoparticles towards better and more sensitive microdroplet for electronic and optical manipulation and other applications.
Two different series of conjugated polymer, poly(m-phenyleneethynylenes) (m-PPEs) containing different amounts of salicylideneaniline moieties (50% and 100%) have been synthesized via a post-functionalization of aniline group on m-PPEs backbone. PPEs are successfully prepared in excellent yield (90-99%) and spectroscopically characterized the structure by $^1$H, $^{13}$C NMR and FTIR exhibited signals that reasonably correlate with the desired polymer. The resulting polymers displayed weak orange emission at 560 nm and undergo remarkable turn-on bright blue fluorescent emission at 450 nm response to Fe$^{2+}$, Fe$^{3+}$, Al$^{3+}$ and Cr$^{3+}$ without any change with other cations.
Observing Chitooligosaccharide Traveling through a Biological Nanopore of Escheriachia coli
H. Sasimali M. Soysa1, 2 and Wipa Suginta*1 ,2
1Biochemistry-Electrochemistry Research Unit, Suranaree University of Technology, Nakhon Ratchasima, Thailand
2School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
Tel: +66-44226187; E-mail: wipa@sut.ac.th
Porins assembled inside the outer membrane of Gram-negative bacteria typically serve as molecular filters, allowing hydrophilic compounds to pass through by either general diffusion or facilitated diffusion process. Porins are composed of β-strands that lie in an antiparallel fashion and form a cylindrical tube, called a β-barrel, with overall dimension of 1-3 nm in diameter and 5 nm in height. In this report, we describe the identification and characterization of chitoporin, namely EcChiP, from Escherichia coli. Using black lipid membrane reconstitution (BLM) technique, we prove that EcChiP could readily form a stable nanopore in artificial phospholipid membranes, permitting an ion flow of average conductance of 0.55±0.01 nS. Together with bulk permeation study by liposome swelling assays, we demonstrate that EcChiP is a sugar-specific transporter, with pronounced specificity towards long-chain chitooligosaccharides. From physiological point of view, this study provides the first evidence that non-chitinolytic bacteria (here is E. coli) can exploit chitin degradation products as alternative energy supply to thrive under glucose-deficient conditions by expressing chitoporin as a molecular gateway for nutrient uptake.
Keywords: Biological nanopore; chitooligosaccharides; single channel conductance; sugar transporter
Supported by Suranaree University of Technology and the Thailand Research Fund.
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Cosmeceuticals from natural products or herbal cosmetics has become the most topic of interest in nowadays cosmetic trend, as they are natural, safe and free from all the harmful synthetic chemicals. Many naturally available herbs serves as active ingredients in different uses for skincare, haircare and antioxidant formulation. However, the application of phytochemical extracts in cosmeceutical products is still challenging due to their stabilities as well as their abilities for skin adsorption and penetration. To address these challenges and to overcome a skin barrier, nanotechnology have been widely applied.
In our Nano-cosmeceutical laboratory, the main focuses are based on the implication of nanotechnology and delivery system in novel cosmeceutical products, especially from Thai medicinal herbs. The expertise also includes an in vitro and cell-based assays for the investigation of bioactivities as well as cosmeceutical efficacies of the extracts for anti-oxidation, anti-ageing, anti-acne, anti-septic, anti-inflammatory, and whitening prior to technology transfer and commercialization.
This current talk gives a brief overview of importance of nanotechnology in cosmeceutical products. It also covers different types of nanoencapsulation systems and carriers in present products including the development of lipid-based nanoparticles such as liposome, noisome, and nanostructured lipid carriers (NLCs). The investigation of bioactivity, biocompatibility and cytotoxicity of these carriers using cell-based assay will be addressed. Finally, our ongoing research on applications of these carrier in cosmeceutical formulation will be also highlighted.
Over the last several decades, there has been tremendous amount of interest in developing novel nanoparticles for drug delivery to cancers. These nanoparticle platforms can be categorized as organic-based (e.g., lipid nanoparticles, biodegradable polymeric nanoparticles, and viral vectors), inorganic-based (e.g., metallic nanostructures, silica nanopartices, and quantum dots), or a hybrid combination of the aforementioned.
The Nano Delivery System Laboratory group of National Nanotechnology Centre has been focusing on the use of nanotechnology for targeted delivery and controlled release of drugs, and biopharmaceuticals, in order to improve their effectiveness for the prevention and treatment of human diseases. Our group has generated a number of nanocarrier platforms and demonstrated their potential for cancer treatment. For example, we investigated the application of modified chitosan biopolymer as a potential vector for suicide gene delivery to cancers related to the reproductive system. We also engineered the bacteriophage-based nanocarrier (derived from a virus of bacteria and non-pathogenic for humans) that has promise in cancer gene therapy. Moreover, our group has reported a number of improved versions of lipid-based nanocarriers such as phospholipid-chitosan nanoliposomes, antibody-directed lipid nanoparticle platforms and mucoadhesive nanostructure lipid carrier (NLC), all of which have great potential for the delivery anti-cancer drug to various types of cancers.
Importantly, numerous nanoparticle platforms are being investigated and therefore require preclinical in vitro studies that accurately represent physiological conditions. In addition to conventional cell culture models, we have developed three dimensional (3D) tumour spheroid models as well as a flow chamber system and evaluated the possibility of using these system as a valuable device to examine efficiency of nanocarrier-mediated anticancer drug delivery and targeting specificity before moving on to animal studies.
This talk covers our current research as well as our previously reported nanocarrier platforms, their conceptual design and development, and the success of these platforms that present a breakthrough in the delivery of anti-cancer agents. This talk will also summarize the established models for in vitro therapeutic screening that have potential to provide reliable information superior to conventional cell culture to improve and optimize drug delivery systems for an effective cancer targeting.
A simple electrochemical aptasensor was developed for the detection of glycated albumin (GHSA) using ssDNA aptamer that selectively binds to GHSA as a recognition element. The biotinylated ssDNA aptamer was immobilized on a streptavidin-modified screen-printed carbon electrode (SPCE). The changes of interfacial features of the electrode surface, which were based on the aptamer-GHSA interaction, were probed in the presence of the reversible redox Fe(CN)63- using square wave voltammetry (SWV) measurements. Our results showed that the minimum detection limit of this sensor was 10 µg/ml with a calibration curve to the range of 16 mg/ml. The aptasensor showed high selectivity for GHSA over other molecules that is usually available in the blood. Importantly, our aptasensor was successfully applied to detect GHSA in blood serum samples, which demonstrated the higher levels of GHSA concentrations in diabetes than normal persons. These indicate that our electrochemical aptasensor has a potential for diagnosis and monitoring of diabetes mellitus.
Magnetofection, a site-specific delivery of nucleic acids to cells guided by a magnetic field, has received increasing attention for its great potential on gene therapy. To promote its clinical therapeutic applications, development of safe and effective magnetic nanocarriers is in high demand. Superparamagnetic iron oxide (SPIO) nanoparticles have been clinically proven safe and used as a magnetic resonance imaging contrast agent approved by Food and Drug Administration. In this work we present an initial study of the development of novel silica-coated SPIO nanoparticles for efficient magnetofection. Our patented silica-coated SPIO nanoparticles have many features including 1) facile synthesis with a 2-hour reaction time (compared to a 24-hour standard Stöber process; 2) stability in biological fluids for a year with low degree of aggregation; 3) lack of degradation and oxidation due to polyvinyl alcohol coating layer; and 4) versatility for surface functionalization and drug loading of the silica shell. In this study, the silica-coated SPIO could efficiently condense plasmid DNA (pDNA) into nanoparticles (PSPIO), which exhibited several favourable properties for gene delivery. In vitro transfection efficiency of PSPIO was significantly enhanced under an external magnetic field in a variety of cancer cell lines and PSPIO were found advantageous over existing nonviral transfection methods with the additional benefit of maintaining high cell viability. The superiority of magnetofection could not be inhibited by serum, and fast accumulation of PSPIO on cancer cells was observed. In conclusion, our results demonstrate that the silica-coated SPIO is a technically simple and effective alternative to current methods for gene transfer as well as molecular imaging under the guidance of a magnetic field. Ongoing and future work includes pharmacokinetic study of PSPIO and tumor-directed gene therapy in vivo.
Diabetes has been one of the major health issues worldwide and also in Thailand. More importantly, almost half of those with diabetes are undiagnosed. Although various test methods have been developed, the existence of anemia and thalassemia may cause inaccuracy in the diabetes mellitus testing from blood. An alternative biomarker molecule is glycated albumin which directly corresponds to the diabetes mellitus. Aim of this work is to utilise nanopore technology to detect level of the glycated albumin. The nanopore was fabricated by Focus Ion Beam technique on a 70 nm thick silicon nitride membrane. The testing system composes of 2 solution chambers separated by the silicon nitride nanopore. Electrochemical technique was performed for 2 purposes, 1) to identify the existence of the nanopore and 2) to determine the analyte shape, charge, and concentration from the ionic current profile during the analysis. Preliminary results suggested that the glycated albumin could be detected by the 100 nm nanopore with electrochemical measurement.