Abstract:
Plasmonic biosensors based on surface resonance plasmon (SPR) and surface-enhanced Raman scattering (SERS) have emerged as a powerful analytical and sensing technique with broad applications, such as food safety, biomedicine, and environmental monitoring, because of the label-free, real-time detection capability offered by SPR biosensors and molecular specificity and high sensitivity enabled by SERS. For the SPR biosensors, I will highlight our recent effort in the development of immunoassays for the detection of extracellular vesicles (EVs) via universal tetraspnins by considering the factors like antibody clonality (monoclonal vs. polyclonal), antibody surface coverage, and tetraspanin-enriched microdomains as well as discuss the limit of detection and antibody-EV binding kinetics. I will showcase our effort on the development of dually functional interdigitated electrodes that can not only sustain SPR mode but also increase bacterial mass transport through external application of dielectrophoresis for the detection of low concentration bacteria. For SERS biosensors, since electromagnetic enhancement dominates the SERS effect due to extremely strong local electric fields (i.e., hot spots) induced by localized surface plasmon resonance (LSPR), the development of plasmonic nanostructures as SERS-active substrates is one of the frontiers in this field. I will first talk about our effort on the development of SERS-active plasmonic nanostructures, including quasi-3-dimension plasmonic nanostructure arrays (Q3D-PNAs) and the nanostructures enabling the extension of electric field, for sensitive detection of small and large analytes. As detection using SERS is typically carried out on bare metal surfaces, because of the near field effect, non-specific adsorption frequently occurs and significantly reduces detection performance. In this regard, I will talk about our effort on the development of stealth surface modification and hierarchical zwitterionic modification for SERS substrates to enable the sensitive and specific detection in protein solution and real-time drug monitoring from blood plasma, respectively.

Speaker Bio:
Qiuming Yu received her B.S. and M.S. in Chemistry from Nanjing University, China in 1985 and 1989, respectively, and her Ph.D. in Chemical Engineering from Cornell University in 1995. She was a postdoctoral fellow in the Micro-devices Laboratory at the NASA Jet Propulsion Laboratory, California Institute of Technology, from 1995-1996. After spending three years as a research assistant professor in Chemical Engineering at Kansas State University, she moved to the University of Washington and was a full professor in the Department of Chemical Engineering. She joined the Robert Frederick Smith School of Chemical and Biomolecular Engineering at Cornell University in July 2020 as a professor.