Enhanced Polymer Transport in a Crowdier Nanoslit Micropost Array

We found enhanced transport of DNA molecules in more crowded nanoslit micropost arrays, contrary to the expectation of slower diffusion in more crowded environments. The nanofabricated post arrays are weakly attractive and emulate crowded interactive environments, resulting in weak DNA adsorption. The coupling between DNA diffusion with adsorption to the microposts results in increased mobility with increasing post density, in contrast to studies of decreased DNA/protein mobility in dense gels. Hidden Markov analysis was employed to identify the apparent free energy barriers, which is in agreement with theoretical estimates of based on polymer conformation fluctuations between posts. We also performed Langevin dynamics simulations of macromolecular transport in micropost arrays to verify the enhanced diffusion in denser arrays. Faster DNA diffusion and hopping in crowded systems have important implications for biological systems and for technological applications such as macromolecule purification, and targeted drug delivery.