Very sensitive measurement of disease-indicating molecules in body fluids is essential for delivering quality healthcare. This project aims to develop a new approach that is expected to be both sensitive and reliable. The new approach is based on synergy of light-excited electron oscillation and chemical reaction occuring simultaneously on specialized nanostructures.
In biosensing, an unmet need is ultrasensitive detection (like polymerase chain reaction, PCR) with accurate quantitation (like enzyme-linked immunosorbent assay, ELISA). This ability is sorely needed for protein biomarkers which cannot be PCR-amplified, or constrained by time, sample quantity, or resources. To meet this need, a novel concept of multimodal signal amplification by collaborative plasmonic intensification and catalytic multiplication (c-PI/CM) is proposed. The central intellectual merit is to exploit the collaborative synergy between PI and CM. Collaborative PI/CM is not simply enhancing one modality by the other, but the collaboration and positive reinforcement between the two modalities. Thus, PI/CM is fundamentally different from, for example, plasmon-enhanced ELISA. To test this hypothesis, the PI will design a series of experiments to elucidate the fundamental mechanisms of c-PI/CM by investigating their interplay on standard plasmonic nanostructures fabricated by nanolithography. A second hypothesis is to test whether c-PI/CM would perform better on recently developed nanoporous gold (NPG) disks which exhibits intrinsic catalytic functions, high-density, three dimensionally distributed plasmonic field enhancement sites (also known as, hot spots), order-of-magnitude larger surface area, and excellent structural integrity and environmental stability, all pointing to a more plausible high-performance c-PI/CM platform. Several in situ monitoring techniques will be used to assess sensing performance: LSPR shift, surface-enhanced Raman scattering (SERS), and surface-enhanced fluorescence (SEF).
