Development of the cytodetachment technique to quantify mechanical adhesiveness of the single cell

Adhesion of cells to biomaterials or to components of the extracellular matrix is fundamental in many tissue engineering and biotechnological processes, as well as in normal development and tissue maintenance. Many cells on adhesive molecules will spread and form an organized actin cytoskeleton and complex transmembrane signaling regions called focal adhesions. Focal adhesions appear to function as both signaling and stabilizing components of normal adherent cell activity. To better understand adhesion formations between cells and their underlying substrata, we have designed, developed, and utilized a novel 'cytodetachment' methodology to quantify the force required to displace attached cells. We allowed bovine articular chondrocytes to attach and spread on a substratum of either fibronectin, bovine serum albumin, or standard microscope glass. The cytodetacher was then employed to displace the cells from the substratum. Our results demonstrate that a significantly greater force is required to detach cells from fibronectin versus the two other substrata, suggesting that a cell's actin cytoskeleton and perhaps focal adhesions contribute significantly to its mechanical adhesiveness. The cytodetacher allows us to directly measure the force required for cell detachment from a substratum and to indirectly determine the ability of different substrata to support cell adhesion.