(392f) Brownian Dynamics Simulations of Electrophoretic DNA Separations in a Conducting Post Array

We use Brownian dynamics simulations and computational fluid dynamics to exam the electrophoretic DNA separations through a conducting post array. Electrophoretic separation of DNA through a post array has been heavily investigated in both experiments and simulations. However, the posts were assumed to be either insulated or having the same conductivity as the buffer solution. In this study, we exam the idea that conducting posts may result in better DNA separation. Since the electric field lines concentrate around the more conductive posts, DNA molecules were expected to have higher probability to collide with the posts and to experience hooking and unhooking events more frequently, leading to better separation. In our simulations, we set the posts to have different degrees of conductivity higher than that of the buffer solution and analyze the average electrophoretic mobility and dispersion coefficient of lambda-DNA (48.5 kbp) and T4GT7-DNA (166 kbp) as they move through the array. However, the simulation results show that DNA separation has not been improved in spite of the higher collision rate. Moreover, in contrast to the observation in the insulated post array, T4GT7 DNA was found to move faster than lambda-DNA. We will explain these rather unexpected results with more detailed analysis.