Switch-like surface binding of competing multivalent particles

TL;DR

This paper presents a theoretical model explaining how multivalent particles exhibit switch-like binding behavior on surfaces depending on receptor density, with potential applications in selective surface binding.

Contribution

A simple theoretical framework is developed to predict switch-like binding behavior of multivalent particles based on receptor density.

Findings

The switch-point depends on receptor concentration and ligand valency.

The theory accurately predicts the switch-like behavior observed in numerical calculations.

Binding selectivity can be controlled by receptor density rather than ligand specificity.

Abstract

Multivalent particles competing for binding on the same surface can exhibit switch-like behaviour, depending on the concentration of receptors on the surface. When the receptor concentration is low, energy dominates the free energy of binding, and particles having a small number of strongly-binding ligands preferentially bind to the surface. At higher receptor concentrations, multivalent effects become significant, and entropy dominates the binding free energy; particles having many weakly-binding ligands preferentially bind to the surface. Between these two regimes there is a "switch-point", at which the surface binds the two species of particles equally strongly. We demonstrate that a simple theory can account for this switch-like behaviour and present numerical calculations that support the theoretical predictions. We argue that binding selectivity based on receptor density, rather than identity, may have practical applications.