ChEMS Seminar: Nanoparticle-hydrogel Interactions: Electrophoresis, Rheology, Electroacoustics, and Optical-tweezing Interferometry
Abstract: Nanoparticles bearing charge and soft coronas are often the intermediate and/or final product of nanoparticle synthesis strategies for smart drug delivery and other biomedical applications. Electrophoresis—including micro-electrophoresis, capillary electrophoresis, and gel electrophoresis—is widely used to characterize these particles, but the interpretation is often challenging. This talk will begin by presenting recent progress using theoretical models and experiments to interpret free-solution and gel-electrophoretic mobilities based on nanoparticle structure and charge, elucidating, for example, several cases of mobility reversal. Next, rheological and electroacoustic studies of hydrogels and their nanocomposites will be discussed. These highlight, for example, universal scaling, and mechanical enhancement arising from multifunctional physical crosslinking. Finally, control of the adhesion of lipid-bilayer functionalized microspheres to polyacrylamide hydrogel films will be demonstrated, as probed by optical-tweezing interferometry. Here, the interaction is controlled by repulsive dispersion forces and an attractive steric interaction/entanglement.
Bio: Reghan J. Hill obtained his B.E. in chemical and materials engineering from the University of Auckland, and Ph.D. in chemical engineering from Cornell University, under Donald L. Koch. His post-doctoral training was in the Department of Chemical Engineering at Princeton University, under Dudley A. Saville and William B. Russel. He is presently an associate professor of chemical engineering at McGill University with research interests in fundamental aspects of soft matter; presently teaching courses in soft matter, process control, and advanced transport.