Measurement of mechanical forces generated by skin fibroblasts embedded in a three-dimensional collagen gel.

Mechanical activities developed by cells play a significant role in the embryogenesis, development, and physiopathology of pluricellular organisms. A technique is described to measure in vitro the traction force developed by cells seeded into a three-dimensional polymeric collagen lattice. It is based on the use of strain gauges generating an electrical signal upon tension that is amplified and recorded. The intensity of the signal depends on the number and type of cells, cytoskeleton integrity, concentration of collagen in the lattice support, and fetal calf serum in the culture medium. Skin fibroblasts from humans and animals produce traction forces ranging from 100 to 1000 mg per million cells. In the gel under tension, the cells are in mechanical dynamic equilibrium with their support. It is suggested that the mechanical activity of fibroblasts and the control of the tension that they operate on the lattice support participate in the structural organization of the dermis and in its physiologic tension.