ChE Seminar: Microfluidic processing of DNA using flow and electric fields

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ABSTRACT:

The efficient and innovative processing of bio-macromolecules relies increasingly on their transport and manipulation within sub-millimeter geometries, or microfluidic devices. The motivation to innovate is clear, as improvements in the ability to detect, concentrate, and separate biologically relevant molecules will accelerate fundamental advances in biomedical technologies, drug discovery, biomedical testing, and more.

In this lecture, I describe a simple method to control the distribution and transport of polyelectrolytes, and DNA in particular, within microfluidic channels. The method uses parallel and anti-parallel flow and electric fields to either migrate DNA toward the channel walls or to focus DNA along the center-line. An electro-hydrodynamic interaction is identified as the physical mechanism that drives the migration; predictions of theories and simulations incorporating these interactions are compared with experimental results as a validation of the proposed mechanism. Furthermore, alternative hypotheses explaining the migration are shown to be invalid or inapplicable.

The revelation that motion exits transverse to the electric field is a previously unrecognized insight into the electrokinetics of polyelectrolytes. This insight can be exploited for biotechnological applications of DNA. As examples, the ability to trap and concentrate DNA using the mechanism is presented. The separation of DNA from other macromolecules and particles in a microfluidic chip of simple design is also demonstrated. This latter process is a promising approach for purifying long-read DNA from lysates.

BIO:

Jason E. Butler is a Professor of Chemical Engineering at the University of Florida (Gainesville, Florida). Dr. Butler completed his doctoral work at the University of Texas at Austin and post-doctoral studies at Stanford University. Prior to joining the faculty at the University of Florida in 2001, Dr. Butler also worked at Aix-Marseille University in Marseille, France, where he still frequently visits and works. Dr. Butler’s research interests encompass dynamic phenomena within complex fluids, and his work spans theoretical, computational, and experimental approaches to resolving questions that impact applications as diverse as microfluidics for bioseparations and slurry flows in the mining industry. Among other achievements, Dr. Butler has contributed to the theory and modeling of sedimentation and rheology of non-spherical particles, the Brownian dynamics of rigid polymers and Brownian rods, and the electrokinetics of polyelectrolytes.