Dynamics of self-interacting bio-inspired polymers in shear flows

Biopolymers interact with each other, triggered by external stimuli, to carry out key biological functions. Blood clotting is a perfect example of that. Triggered by the shear of the flowing blood, the giant von Willebrand factor (VWF) adhesive protein establishes specific interactions with several partners, including with itself via specific protein-protein auto-inhibitory interactions. However, the impact of such self-interactions on the flow-induced non-equilibrium conformational dynamics of such polymers remained unclear. We tackled this question by implementing Brownian dynamics simulations at a coarse-grained resolution of VWF-like self-interacting biopolymers. In the absence of specific interactions, we recapitulated previous estimates of the critical shear-rate upon which the polymer underwent a globular-to-stretched conformation. Introduction of specifically interacting points within the polymer, increased the critical shear-rate roughly by an order of magnitude. Accordingly, our data demonstrate that the state of self-interacting biopolymers, under shear flows, can be effectively tuned by increasing either the number or the strength of self-interacting units. This information is highly useful to understand how specific-molecular interactions modulate VWF assembly.