(222e) Experimental Study of DNA Electrophoresis in Post Array with Pulsed Electric Field

Microchannels with post array have been shown capable of separating long DNA in relatively short period of time than the conventional gel. However, the efficiency of the post array has been found decreased rapidly with increasing Peclet number (or electric field) due to the onset of the “channeling” phenomenon that DNA move through the hypothetical “channel” without collisions with the posts. In this study, we experimentally test the idea that using pulsed electric field with post array can attenuate the channeling phenomenon and regain the separation efficiency at high electric field. We have fabricated microchannels with array of posts of 1 micron in diameter on fused silica using standard photolithography and inductively coupled plasma (ICP) etching. The separation efficiency as a function of Pe is determined by measuring the electrophoretic mobility and the dispersion coefficient of λ-(48.5kbp) and T4(165.6kbp) DNA. The effect of the frequency and extension of the electric field pulse on the efficiency of DNA separation is also investigated.