Dynamics of particles with “key-lock” interactions

Department of Physics and Michigan Center for Theoretical Physics, University of Michigan 450 Church Str., Ann Arbor, MI 48109, USA

Received: 4 October 2007
Accepted: 21 December 2007

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. In the localized regime at low coverage, the system exhibits an exponential 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.