FPCL is a useful functional assay that measures collagen contraction in vitro. Researchers studying wound healing and Dupuytren's disease (DD) have empoyed this assay to quantify collagen contraction, an important physiological event for both biological processes, in response to changes in mechanical stress or various agents (both contraction agonists or antagonists). Unlike traditional 2-dimensional (2D) cultures, FPCL assays provide a 3D matrix environment that reproduces many of the in vivo aspects of DD and wound healing. As shown in Figure 1, FPCLs are essentially a mixture of cells and collagen (predominantly type I with some type III, although the ECM composition can be altered to study its affects on contraction). The mixture spontaneously polymerize when placed at 37°C (~1hr) and can be cultured attached to the sides of wells (24 well plates) for several days in order to build up isometrix tension. The lattices are then mechanically released from the sides of the dishes, allowing the cells to contract the collagen matrix. The amount of contraction can then be measured and quantified.