Cilia Induced Bending of Paramecium in Microchannels

Most living organisms in nature have a preferential gait and direction along which they locomote, presumably derived from the evolutionary/mechanical advantage provided by the gaits. However under the influence of constrained geometries, organisms often exhibit peculiar locomotory characteristics. A Paramecium in its natural state preferentially swims in a helical path in the anterior direction. When introduced into channels with dimensions smaller than its length, a posterior swimming Paramecium bends its flexible body, executes a flip, and swims in the anterior direction again. We study the deformation of the body shape caused by forces generated by beating cilia, which are assumed to be acting at the tip of the organism. This method may lead to a non-invasive method of measuring the forces exerted during bending by self propelling organisms having high aspect ratio.