Abstract
The adsorption of a single collapsed homopolymer onto a planar smooth surface in shear flow is investigated by means of Brownian hydrodynamics simulation. While cohesive intra-polymer forces are modeled by Lennard-Jones potentials, surface-monomer interactions are described by stochastic bonds whose two-state kinetics is characterized by three parameters: bond formation rate, bond dissociation rate and an effective catch bond parameter that describes how the force acting on a surface-monomer bond influences the dissociation rate. We construct adsorption state diagrams as a function of shear rate and all three surface-monomer bond parameters. We find shear-induced adsorption in a small range of parameters for low dissociation and association rates and only when the surface-monomer bond is near the transition between slip and catch bond behavior. By mapping on a simple surface-monomer interaction model with conservative pair potentials we try to estimate the conservative potential parameters necessary to observe shear-induced surface adsorption phenomena.
Highlights
Some biological bonds exhibit prolonged lifetimes in the presence of tensile forces, a counter-intuitive phenomenon referred to as catch bond behavior [1,2]
While cohesive intra-polymer forces are modeled by Lennard-Jones potentials, surface-monomer interactions are described by stochastic bonds whose two-state kinetics is characterized by three parameters: bond formation rate, bond dissociation rate and an effective catch bond parameter that describes how the force acting on a surface-monomer bond influences the dissociation rate
The present study is motivated by the blood protein von Willebrand Factor (VWF), which plays a key role in hemostasis [11] by unfolding and activation at elevated shear rates and subsequent binding to the vessel wall [11,12,13]
Summary
Some biological bonds exhibit prolonged lifetimes in the presence of tensile forces, a counter-intuitive phenomenon referred to as catch bond behavior [1,2]. We study the adsorption of globular polymers by stochastic two-state surface-monomer bonds, which is a model that for particular parameter values was previously shown to lead to shear-induced adsorption [17]. Similar models with simple two-state kinetics have proven useful in a number of studies since it is relatively straightforward to include the force-dependent bond stability in a heuristic manner so that either slip or catch bond behavior is obtained [17,18,19,20,21]. We present adsorption state diagrams as a function of shear rate, the surface-monomer bond dissociation and association rates and an effective catch bond parameter that describes the continuous change from slip to catch bond behavior.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
