A nonlinear characteristic regime of biomembrane force probe.

A linear relation between stiffness and aspiration pressure is the basis for biomembrane force probe (BFP), a widely used technique to measure minuscule forces. Here we perform finite element simulations and semi-analytical modeling of the BFP operation to show that, at low aspiration pressures, there exists a characteristic regime in which the relation between stiffness and aspiration pressure is actually nonlinear. We find that this nonlinear characteristic regime arises from a transition in configuration of a partially aspirated biomembrane force probe under increasing aspiration pressure. We discuss both the conditions for the transition and the characteristics of the nonlinear characteristic regime, as well as its potential applications.