Stress concentration at the base of primary cilium due to application of a thin elastic layer

Primary cilium is an organelle in approximately every cell in the body. It is believed to play a major role in sensing mechanical stimuli including shear strain exerted by fluid flow. In previous studies, researchers modeled this organelle as a cantilevered beam attached to the cell surface. In the present study we cast doubts on this assumption and modeled cilium in a way that cilium base was free to change direction so that a variable angle forms between cilium base and cell surface. This is done by application of a thin elastic layer with adjustable spring constant between bottom of the cilium and surface of the cell. In this case, extremely concentrated stress develop in small regions near the cilium base where a huge number of stretch-activated ion channels exist. From a biological point of view, this stress concentration effect brings about an enhanced and more sensitive primary cilium which is able to respond to minor stimuli.