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The seminar has moved to CP-220.  



Dr. Franz Geiger of Northwestern University will be presenting a seminar titled Direct Views of the Nano-Bio Interface.

Abstract:  The tendency of proteins, lipids, and other biological species to form coronas around nanoparticles has been put to great use for promoting or inhibiting cellular uptake of engineered nanomaterials. This situation raises the question whether lipid coronas can form spontaneously at the interfacial region between a nanomaterial and a biological membrane, i.e. the nano nano-bio interface, and thereby regulate cellular uptake. Here, we describe the interaction of a well-characterized set of ligand-coated nanoparticles with lipid bilayers of varying chemical composition, the gram-negative bacterium Shewanella oneidensis, and a multicellular organism, the water flea Daphnia magna. Using nanoparticle- and membrane-specific data from microscopy, spectroscopy, and mass measurements, we determine that particles coated with cationic polyelectrolytes disrupt largely zwitterionic bilayers under electrostatically attractive conditions while all other particle-ligand combinations surveyed leave the bilayers intact. Moreover, we report that bilayer disruption coincides with lipid corona formation around the particles and propose this mechanism as the molecular basis for a nanoparticle-specific effect that lowers the survival rate of D. magna when they are exposed to particles wrapped in cationic polyelectrolyte.  Finally, we demonstrate the key role of lipopolysaccharides in protecting S. oneidensis from nanoparticle uptake.

Refreshments will be served at this event.

Faculty Host: Dr. Marcelo Guzman