Speaker
Prof.
Aleksander Bilewicz
(Institute of Nuclear Chemistry and Technology, Poland)
Description
Ra-223, Ra-224 and Ra-225, among others alpha-emitting radionuclides, have attractive properties for use in targeted radionuclide therapy. Unfortunately, Ra2+ cations like other cations of the II group, forms very weak complexes, therefore labeling of the biomolecules with 223,224,225Ra is a very difficult task. On the other hand, some zeolites exhibit very high affinity for Ra2+ cations.
In our studies we propose to use nanozeolite as a carrier for transportation of 223,224,225Ra radionuclides to the tumor sites. Due to high ion exchange affinity, nanozeolites strongly bind radium cations and additionally, as aluminosilicates, nanozeolites could be easily attach to biomolecules by silanol-amine/carboxyl linkers.
Nanozeolite of type A (20-70 nm diameter) were synthesized by hydrothermal method. Next, the surface of the nanozeolites was modified by attaching polyethylene glycol (500 - 600 daltons) containing silanol group on the one end and active ester on the second end. The obtained samples were examined for encapsulation of 224Ra and 225Ra (milked from 228Th/224Ra and 229Th/225Ra generators). The stability of radiolabeled nanozeolites were examined in 0.9% NaCl, 0.02 M PBS, 0.001 M cysteine and glutathione and human serum. In the case of 224Ra, about 2% of gamma-radioactivity was found in the solution, which has been attributed to 212Pb - the decay product of 224Ra, while, in the case of 225Ra even above 15% of activity was found in the solution. The activity has been ascribed to 225Ac and 213Bi - the decay products of 225Ra. In the next steps we plan to stabilize 225Ra and all daughter radionuclides in nanozeolite structure. After that, the conjugation of the modified nanozeolites with two vector peptides – octreotide and substance P will be made.
Author
Ms
Agata Kasperek
(Institute of Nuclear Chemistry and Technology, Poland)
Co-authors
Prof.
Aleksander Bilewicz
(Institute of Nuclear Chemistry and Technology, Poland)
Edyta Leszczuk
(Institute of Nuclear Chemistry and Technology)
