Authors: P.J. Atzberger, F. Gibou, S. Pennathur
Affilation: University of California Santa Barbara, United States
Pages: 454 - 457
Keywords: separation, electrophoresis, nanochannel
Electrophoretic separation in nanofluidic channels exhibits significant differences with microfluidics. We discuss a theoretical / experimental collaboration investigating particle separation by electropohoresis in nanochannels. Recent experimental results in the laboratory of our collaborator Dr. Pennathur (UCSB, Dept. ME) indicate that increased fidelity can be achieved in separating particles by size and charge when using channels with cross sections of nanometer dimensions (100nm x 1000nm), as opposed to larger microfluidic channels. For short double-strands of DNA (10 - 100 base pairs) it is found that separation in microfluidic channels produces electropherograms with only one lumped peak. However, for nanofluidic channels several clearly distinct peaks are observed. Given the small dimensions of the nanofluidic channel, it is expected that new effects which were relatively weak in microfluidic channels play an important role. Identifying how these underlying mechanisms augment electrophoretic mobility poses significant experimental and theoretical challenges. In this work, we report on our investigations of the role of the large surface area to volume ratio, steric restrictions imposed on molecular configurations, the overlap of double layers of the wall and analyte molecules, the coupling of electrical currents and hydrodynamic flow, and the translational and rotational diffusion of analyte molecules. We compare our theoretical results with the electropherograms of double-stranded DNA separations.