Enhanced bacterial motility in colloidal media
ORAL
Abstract
The study of the locomotion of biological and artificial microswimmers in Newtonian and non-Newtonian fluids is gaining rapid momentum with applications in many areas such as pathogenicity, bioremediation, and drug delivery. Here, we experimentally investigate the motility of Escherichia coli, a flagellated bacterium, in colloidal media. We systematically vary the size of passive colloidal particles in the mixture from 20 nm to 1 μm and the volume fraction up to 20%. Using confocal microscopy, we image the motion of fluorescent-labeled bacteria and implement an in-house tracking algorithm to obtain the speeds of bacteria. We observe a substantial increase in bacterial speeds (up to 74%) as the colloid volume fraction increases to 3%, followed by a decrease at higher volume fractions. Additionally, we find that increasing the size of colloidal particles results in larger speed enhancement. We construct a model that qualitatively explains our experiments. Our study highlights the unusual locomotion of swimming microorganisms in colloidal suspensions and illustrates the rich dynamics that arises from swimmers’ interactions with their environment.
–
Presenters
-
Shashank Kamdar
Department of Chemical Engineering and Materials Science, University of Minnesota-twin cities
Authors
-
Shashank Kamdar
Department of Chemical Engineering and Materials Science, University of Minnesota-twin cities
-
Lorraine F. Francis
University of Minnesota, Department of Chemical Engineering and Materials Science, University of Minnesota-twin cities
-
Xiang Cheng
Chemical Engineering and Materials Science, Universitiy of Minnesota, University of Minnesota, Department of Chemical Engineering and Materials Science, University of Minnesota, Department of Chemical Engineering and Materials Science, University of Minnesota-twin cities