(306g) Physical and Chemical Approaches for Enhancing Optical Biosensors

Optical 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, homeland security, 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 cover our recent effort in the development of dually functional interdigitated electrodes to sustain SPR and to 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.