Feel the force: using a bed of needles to map single cell generated traction forces

Understanding of how cells exert and respond to mechanical forces depends on the ability to measure the origin and magnitude of those forces at subcellular resolutions. We have developed a novel system to measure cell contractility by culturing cells on top of an array of micrometer scale elastomeric posts. Each post in the array independently bends in response to local forces exerted by the attached cell. We demonstrate that the system can consistently measure cell traction forces with a high degree of precision in real time. We use this system to measure the contractility of cells spread to different degrees. We found that cell spreading is required for cells to organize its actin cytoskeleton and exert traction force on the underlying substrate.