Influence of Polymer Shape on Depletion Potentials and Crowding in Colloid-Polymer Mixtures

TL;DR

This study investigates how polymer shape fluctuations influence depletion interactions and crowding effects in colloid-polymer mixtures through simulations and comparisons with theoretical and experimental data.

Contribution

It introduces a model of polymers as fluctuating ellipsoids to analyze their impact on depletion potentials and crowding in colloid-polymer systems.

Findings

Polymer shape fluctuations significantly affect depletion interactions.

Simulation results align well with density-functional theory and experiments.

Polymer shape influences crowding behavior in biological and colloidal systems.

Abstract

Depletion-induced interactions between colloids in colloid-polymer mixtures depend in range and strength on size, shape, and concentration of depletants. Crowding by colloids in turn affects shapes of polymer coils, such as biopolymers in biological cells. By simulating hard-sphere colloids and random-walk polymers, modeled as fluctuating ellipsoids, we compute depletion-induced potentials and polymer shape distributions. Comparing results with exact density-functional theory calculations, molecular simulations, and experiments, we show that polymer shape fluctuations play an important role in depletion and crowding phenomena.