Authors: F. Tessier and G.W. Slater
Affilation: University of Ottawa, Canada
Pages: 84 - 87
Keywords: microfluidics, electrophoresis, ratchet, DNA
We present Monte Carlo simulation results for the motion of long linear polyelectrolytes inside a microchannel of molecular dimensions, structured as a periodic array of wells linked by narrow constrictions. Molecules are driven in the channel by a low-intensity electric field, which we model realistically by solving the Laplace equation numerically inside the channel. Our results agree with the counterintuitive experimental observation that longer molecules advance faster than shorter ones, and we show how this separation capability is related to the conformational changes of the molecule as it approaches a constriction. We further discuss possible improvements to the original channel design using pulsed fields, notably by exploiting ratchet operating modes and resonance effects. We support these new ideas with calculations in the zero-frequency limit and simulations in the finite frequency domain.