Effective surface interactions mediated by adhesive particles

TL;DR

This paper develops a statistical-mechanical model to understand how adhesive particles mediate surface interactions, revealing a non-monotonic dependence of adhesion energy on particle concentration with implications for biomembrane adhesion.

Contribution

The study introduces a general model for surface interactions mediated by adhesive particles, highlighting the maximum adhesion at intermediate concentrations and extending to biological and colloidal systems.

Findings

Effective adhesion energy peaks at intermediate particle concentrations.

Secondary minimum in interaction potential at surface contact.

Implications for biomembrane adhesion and colloidal phase transitions.

Abstract

In biomimetic and biological systems, interactions between surfaces are often mediated by adhesive molecules, nanoparticles, or colloids dispersed in the surrounding solution. We present here a general, statistical-mechanical model for two surfaces that interact via adhesive particles. The effective, particle-mediated interaction potential of the surfaces is obtained by integrating over the particles' degrees of freedom in the partition function. Interestingly, the effective adhesion energy of the surfaces exhibits a maximum at intermediate particle concentrations, and is considerably smaller both at low and high concentrations. The effective adhesion energy corresponds to a minimum in the interaction potential at surface separations slightly larger than the particle diameter, while a secondary minimum at surface contact reflects depletion interactions. Our results can be generalized to surfaces with specific receptors for solute particles, and have direct implications for the adhesion of biomembranes and for phase transitions in colloidal systems.