DNA Dynamics in Microfluidic Devices

Owing to the continual advances in micro- and nano- fabrication techniques, the study of particle dynamics has taken on renewed importance. Understanding the detailed dynamics of single macromolecules in microdevices is essential to the practical development and ultimate utility of these devices. My work focuses on understanding how macromolecules, particularly long chain polymers, behave when the variations in the devices are on the same order as the molecules themselves: the precise situation arising in microfluidic devices.

Currently there is demand for improved techniques to separate genomic DNA. In this group we are working to develop separation methods than could one day supplant current gel and capillary electrophoresis techniques. Using theory, computation and experiments (with UC Berkeley) we are studying the properties of long chains in precisely machined arrays of posts to serve as a DNA sieving medium. As an extension of this work we are also investigating the use of post fields to stretch DNA, thus exposing the genetic information, and probing sequences by binding site specific tags.

Continuing with this theme, we are also studying the dynamics of long chains when confined to geometries on the same scale as the chain. Using stagnation point flows at both free points and at boundaries, we are extending chains and probing for the presence of particular gene sequences. The purpose of this work is twofold since before attempting to bind tags we must first investigate chain behavior in confined geometries. These dynamics are much different than those in large macroscopic flows, and a precise knowledge of how the chains behave is imperative in variety of fields, including the modeling of the macroscopic rheology of polymer solutions and single chain microfluidic manipulation.