Abstract for the talk at 20.05.2014 (16:00 h)

Colloquium of the Faculty of Physics and Geosciences

Michael Cates (University of Edinburgh, School of Physics and Astronomy, United Kingdom)
The Physics of Cellular Motility

Cells attached to walls or in tissues can propel themselves by a variety of mechanisms. These are generally discussed in terms of the complicated biochemical feedbacks present in every cell. Here I will instead explore a physics-based approach: what is the simplest combination of physical ingredients that can allow cells to swim or to crawl through their surroundings? I will present a minimal model of cell propulsion based on an emulsion droplet of active polar liquid crystal. This object can swim through a bulk fluid by a mechanism that may (but need not) involve spontaneous symmetry breaking. When attached to a wall and subjected to suitable boundary influences, the droplet can also crawl. These results are possibly suggestive of a 'motility engine' whose function, although controlled by the cell's complex biochemical feedback networks, does not depend upon these for its operational principles.