Cell organization in soft media due to active mechanosensing

I. B. Bischofs and U. S. Schwarz

Proc. Natl. Acad. Sci. USA 100: 9274-9279 (2003)

Adhering cells actively probe the mechanical properties of their
environment and use the resulting information to position and orient
themselves. We show that a large body of experimental observations can
be consistently explained from one unifying principle, namely that
cells strengthen contacts and cytoskeleton in the direction of large
effective stiffness. Using linear elasticity theory to model the
extracellular environment, we calculate optimal cell organization for
several situations of interest and find excellent agreement with
experiments for fibroblasts, both on elastic substrates and in
collagen gels: cells orient in the direction of external tensile
strain, they orient parallel and normal to free and clamped surfaces,
respectively, and they interact elastically to form strings. Our
method can be applied for rational design of tissue
equivalents. Moreover our results indicate that the concept of contact
guidance has to be reevaluated. We also suggest that cell-matrix
contacts are upregulated by large effective stiffness in the
environment because in this way, build-up of force is more efficient.