A two-dimensional mathematical model for cells migrating without adhesion
capabilities is presented and analyzed. Cells are represented by their cortex,
which is modelled as an elastic curve, subject to an internal pressure force.
Net polymerization or depolymerization in the cortex is modelled via local
addition or removal of material, driving a cortical flow. The model takes the
form of a fully nonlinear degenerate parabolic system. An existence analysis is
carried out by adapting ideas from the theory of gradient flows. Numerical
simulations show that these simple rules can account for the behavior observed
in experiments, suggesting a possible mechanical mechanism for
adhesion-independent motility.Comment: 22 pages and 9 figure