Eur. Phys. J. Special Topics 225, 1673-1682 (2016)
https://doi.org/10.1140/epjst/e2016-60119-6

Regular Article

Switch-like surface binding of competing multivalent particles^{*, **}

Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK

^a e-mail: nicholas.b.tito@gmail.com

Received: 15 April 2016
Revised: 8 June 2016
Published online: 18 July 2016

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.