28 May 2017 to 2 June 2017
Queen's University
America/Toronto timezone
Welcome to the 2017 CAP Congress! / Bienvenue au congrès de l'ACP 2017!

Examining the role of bias versus swimming in superdiffusion

30 May 2017, 16:15
Miller Hall 105 (Queen's University)

Miller Hall 105

Queen's University

CLOSED - Oral (Student, In Competition) / Orale (Étudiant(e), inscrit à la compétition) Physics in Medicine and Biology / Physique en médecine et en biologie (DPMB-DPMB) T4-7 Biomechanics and Fluid Dynamics (DPMB) | Biomécanique et dynamique des fluides (DPMB)


Mr Boris Barron (York University)


A key biophysical consideration in cellular biology is the role of motility. That is, can (and how does) a cell move in a preferred direction on its own accord (i.e., swim) for some physiological purpose (e.g., a bias due chemotactic gradient). One means to empirically characterize the result is by quantifying the so-called ‘anomalous diffusion,’ which directly arises from biases, of an ensemble of cells. Commonly, the observed response is that of superdiffusion, where the ensemble mean-squared displacement (MSD) is supra-linear (i.e., MSD exhibits a nonlinear time dependence with an exponent greater than unity). However, if the bias led to cell attraction (i.e. movement towards a localized high-oxygen concentration) the response is reversed. This suggests that quantification of the deviation from linearity can lead not only to distinguish cells which are capable of motility but also the degree, or strength, of their motion bias. Here we develop a heuristic computational model for E. coli motility to distinguish between swimming biases using the macroscopic effect on the MSD. Initial results indicate that objects which are motile, yet lack bias, exhibit characteristics consistent with normal diffusion. This observation motivates a deeper biophysical question as to how/if swimming and bias can be meaningfully disentangled and suggests that direct comparison to the diffusive motion, of similarly-sized not motile objects, under the same conditions is necessary.

Primary author

Mr Boris Barron (York University)


Christopher Bergevin (York University)

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