As part of their physiological functions, most cells need to adapt to their mechanical environment. In particular, the rigidity of the extracellular matrix was shown to control cell traction forces, shape, and ultimately cell differentiation. In this context, most studies focused on the role of biochemical regulation in rigidity sensing.

In contrast to this biochemical signaling-centered approach, our aim is to reveal the physical/mechanical phenomena involved in mechanosensing. To this end, we have developed original single-cell techniques combining mechanical measurements (traction force, mechanical power…) with monitoring of cell structures (evanescent wave microscopy). In particular, we have designed a unique protocol allowing us to change the effective stiffness felt by a single cell in real time (~0.1 second), thus allowing us to show that an early purely mechanical response of single cell to stiffness indeed does exist.

We will present the results of experiments combining single-cell traction force measurements, dynamic control of stiffness, and monitoring of adhesion complexes, and will discuss how cell shape (~ contact angle) and mechanical adaptation to rigidity (~ impedance matching) could control cell fate.