Measurement of cell forces using a microfabricated polymer cantilever sensor

A polymer MEMS sensor was developed for measuring the mechanical forces generated by single adherent cells. Mechanical forces are known to play a role in cell regulation, and measuring these forces is an important step in understanding cellular mechanotransduction. The sensor consisted of four polystyrene microcantilever beams with cell adhesion pads at the end of each beam. Finite element analysis was used to guide the design of a compound cantilever to allow measurement of forces in any direction in the plane of the sensor. The device was used to measure the forces generated by WS1 human skin fibroblasts under a microscope. Single cells were placed on the sensor using a custom micromanipulator. Forces were calculated by optically measuring the deflection of each probe during cell attachment and spreading. Measurements were performed on normal WS1 fibroblast cells and those treated with cytochalasin D to disrupt the actin cytoskeleton. Cytochalasin D treated cells showed a significant decrease in force, with time information about the rate of force change obtained from the sensor. This device can be used to evaluate the mechanical response of cells to a variety of chemical, mechanical, and other environmental stimuli.