Sorting of chiral microswmmers
Author
Mijalkov, Mite
Advisor
Volpe, Giovanni
Date
2014Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Microscopic swimmers, for example chemotactic bacteria and cells, are capable of
directed motion by exerting a force on their environment. In some cases, including
bacteria and spermatozoa swimming near boundaries, or many asymmetrical artificial
microswimmers, the driving force and propulsion direction are misaligned.
In those situations a torque acting on the microswimmers arises, resulting in motion
with a well-defined chirality which is circular in two dimensions and helicoidal
in three dimensions. In this thesis, I demonstrate with numerical simulations in
two dimensions, how the chirality of the circular motion can couple to chiral features
present in the microswimmer environment. I show that by employing static
chiral pattern of elliptical obstacles in their environment, microswimmers can be
separated on the basis of their motion parameters. In particular, levogyre and
dextrogyre microswimmers as small as 50nm can be separated and selectively
trapped in chiral flowers of ellipses. Patterned microchannels can be used as funnels
to rectify the microswimmer motion, as sorters to separate microswimmers
based on their linear and angular velocities, and as sieves to trap microswimmers
with specific parameters. I also demonstrate that these results can be extended
to helicoidal motion in three dimensions.