(527e) A Microfluidic Toolbox To Experimentally Probe Macromolecular Transport During Gel Electrophoresis: Insights and Opportunities

This presentation describes our efforts harness miniaturization as a tool to obtain an improved fundamental understanding of biomolecular separations using gel electrophoresis. Our experimental approach is based on a microdevice design that incorporates on-chip arrays of electrodes, heaters, and temperature sensors. By embedding electrodes directly within the microchannel network and using a photocurable crosslinked polyacrylamide matrix, we are able to perform rapid high-resolution analysis of mobility and dispersion (band broadening) during separations of both single- and double-stranded DNA. These individually addressable electrode arrays can also be used to sequentially concentrate, focus, meter, and inject DNA into the separation matrix. In parallel with this experimental capability, we have also worked to obtain a detailed picture of average pore size and degree of polydispersity in crosslinked polyacrylamide hydrogel matrices. Our approach uniquely combines complementary information from transmission electron microscopy, in-situ dynamic mechanical analysis, and thermoporometry in a way that enables both the mean pore size and the pore size distribution to be quantitatively characterized. Insights obtained from these studies have enabled us to determine how to access a transport regime dominated by entropic trapping. Macromolecular transport in this regime can be synchronized to establish a resonance effect whose size-dependence can be exploited both to achieve improved separation resolution and as a new sensitive structural probe of DNA binding interactions.