SCHOOL OF CHEMICAL, BIOLOGICAL &
MATERIALS ENGINEERING
The University of Oklahoma
Norman, Oklahoma
2005 – 2006 Seminar Series
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DR. MICHAEL D. GRAHAM
PROFESSOR
DEPARTMENT OF CHEMICAL AND BIOLOGICAL ENGINERING
UNIVERSITY OF WISCONSIN - MADISON
MADISON, WISCONSIN
Will present a seminar on
“DNA DYNAMICS IN A MICROCHANNEL:
CONFINEMENT AND BOUNDARY EFFECTS
IN FLOWING POLYMER SOLUTIONS”
The structure, dynamics, and flow of complex fluids through nano- and micro-fluidic
geometries are at the heart of numerous proposed technologies, from accurate and inexpensive
genome mapping systems to fast and reliable sensors for pathogens and toxic chemicals. In
particular, emerging technologies for single molecule analysis of DNA in micron and smaller
scale devices have fueled considerable interest in the structure and dynamics of solutions of
long-chain polymers in confined geometries.
We have developed multiscale simulation methods for studying the dynamics of solutions of
long DNA molecules in microchannels. Detailed simulations of diffusion and relaxation of chains
confirm the predictions of a simple scaling theory, due to de Gennes and coworkers, that is
based on the screening of segment-segment hydrodynamic interactions by the confining walls.
More interestingly, during pressure-driven flow, the simulations predict that molecules migrate
toward the centerline of the channel. The effect is larger for longer molecules, providing a
means for selectively "focusing" very long DNA molecules at the center of a channel. Migration
has been widely observed in polymer solutions but heretofore poorly understood. We show
that the dominant migration effect arises from the fluid motion induced by a DNA molecule as it
tumbles around in the flow, and cannot be captured if the hydrodynamic effects of confinement
are ignored. In addition, an analytical theory for polymer transport that includes hydrodynamic
wall effects was developed; this can used to predict transient and spatially developing
concentration profiles for dilute polymer solutions in confined geometries.
THURSDAY, FEBRUARY 9, 2006
COOKIES AND COFFEE -- 2:45 P.M.
SEMINAR -- 3:00 P.M.
SARKEYS ENERGY CENTER, ROOM N-202A
THIS IS A REQUIRED SEMINAR FOR CHE 5971