Having a rheological bent to my thoughts, I was struck by this question which does not seem to have been raised:
When the cell pulls on the substrate, is the pulling continuous or, as occurs in dynamic mechanical analysis, is it modulated in some manner?
Certainly the latter approach would be able to help the cell better understand the substrate, and given that large molecules such as proteins naturally oscillate, it is not inconceivable that the adherents of the cell would too. This can be important as in all the cases that I’ve seen, the modulus of the substrate is taken as a constant, an assumption that clearly needs to be questioned when the substrate is a softer viscoelastic gel.
So are cells the worlds smallest rheologists?