Ion Drive for Vesicles and Cells

Non-uniform ion pumping across the bounding membrane of a biological cell or artificial vesicle can generate electro-osmostic effects. Self-propulsion of cells at speeds of up to several microns per second is possible. Viscous stresses are generated that lead to significant distortion for a membrane lacking considerable reinforcement by, for example, a cytoskeleton, even if immobilized by adhesion to a substrate. A relation between magnitudes of self-induced effects and the measured electrophoretic mobility is shown.