Capillary Electrophoresis in Nanofluidic Channels

We investigate electrokinetic transport of nanoparticles and biomolecules in nano-scale channels exhibiting novel features in comparison to microscale channels. Recent experimental work provides information about how the mobility and diffusivity depend sensitively and nonmonotonically on pH, ionic valence, and channel size. We discuss a TIRFM platform in which single quantum dot nanoparticles are used to probe in three dimensions single-particle transport through nanochannels. We also discuss studies at the ensemble level of both nanoparticles and biomolecules (e.g. oligoucleotides). We focus particularly on theoretical investigations toward explaining these experimental findings. We study as ionic concentration and valence are varied the role of particle proximity to the channel walls, the role of the electric double layer structure around the wall and particles with possible overlap, and the role of solvent hydrodynamic coupling.