Micah Dembo

Department of Biomedical Engineering, Boston University

Cells exert forces on their external environment for a variety of reasons; for example to crawl, to rearrange than deform the extracellular matrix, and to send and receive information. A longstanding goal of cell biology is to measure and quantify these very tiny forces, in situ, while perturbing the cell as little as possible. I will describe a methodology we have developed for reaching this goal. It involves plating a cell on an elastic material of known mechanical properties, observing the way the substrate deforms, and then utilizing detailed knowledge of substrate mechanics as a basis for deducing the exact magnitude and placement of the cellular traction forces. This last step typically requires the solution of an ill-conditioned integral equation subject to various nonlinear constraints. We will describe the way this problem can be solved numerically and we will then go on to discuss a few practical applications that combine this method with other more classical techniques to yield new insights into the mechanics and control of cell motion and into the molecular biology, physiology and pathology, of force production at the cellular level.