Dynamics of particles with "key-lock" interactions

TL;DR

This paper theoretically investigates particle dynamics with key-lock biomolecular interactions, revealing a transition from localized to diffusive regimes and connecting findings to experimental systems like DNA-functionalized colloids.

Contribution

It introduces a theoretical framework predicting two distinct dynamical regimes and the transition between them based on coverage, with implications for understanding biomolecular particle behavior.

Findings

Low coverage leads to broad departure time distributions.

Higher coverage causes a transition to diffusive and subdiffusive behaviors.

The dynamics resemble glassy aging and dispersive transport in semiconductors.

Abstract

The dynamics of particles interacting by key-lock binding of attached biomolecules are studied theoretically. Examples of such systems include DNA-functionalized colloids as well as nanoparticles grafted with antibodies to cell membrane proteins. Depending on the coverage of the functional groups, we predict two distinct regimes separated by a percolation transition. In the localized regime at low coverage, the system exhibits a broad, power law like distribution of particle departure times. At higher coverage, there is an interplay between departure dynamics and particle diffusion. This interplay leads to a sharp increase of the departure times, a phenomenon qualitatively similar to aging in glassy systems. This diffusive regime is analogous to dispersive transport in disordered semiconductors: depending on the interaction parameters, the diffusion behavior ranges from standard diffusion to anomalous, subdiffusive behavior. The connection to recent experiments and implications for future studies are discussed.