DESCRIPTION (provided by applicant): Plasmonic biosensors have greatly overcome the limitations of conventional optical sensors in terms of sensitivity, tunability, photo-stability, ad in vivo applicability. However, the concerns with average sensitivity, detection specificity, surface functionalities, and device expense still cannot meet the application requirement of point-of-care and personal diagnosis. In this research, the PIs at Oregon State University propose to explore dual-mode plasmonic biosensors using bioenabled nanomaterials --- diatom biosilica, with active surface-functionalities as affordable and eco-friendly integration platforms of Ag nanoparticles for label-free detection of biomolecules. Diatoms are single-celled algae that make silica shells or frustules with intricate nanoscale features imbedded within periodic two-dimensional pore arrays. The essence of this research is addressed by exploration of the unique Fano-resonant hybrid modes between silver nanoparticles and diatom frustules, which leads to high-Q resonant peaks and enhanced local electric field that can significantly enhance the light-matter interactions. Dual-mode plasmon sensing mechanisms, including surface-enhanced Raman scattering (SERS) and refractive-index (RI) sensing will be simultaneously implemented on the plasmonic-biosilica nanostructures to obtain quantitative biosensing with structural resolution of the biomolecules. In addition, the nano-corrugated surface of diatom frustules will help to increase the possibility of capturing various biomolecules. Other exclusive advantages include affordable cost and eco- friendly fabrication of the sensor chips that are completely free of expensive photolithography and other nanofabrication processes, and easy expandability to sensor arrays for high throughput diagnostics, which can provide greater accessibility for large-scale screening. Such unique plasmonic-biosilica sensors with unprecedented figure-of-merits can be used as disposable biosensors to acquire clinically relevant information for the physician and clinician in point-of-care, personal diagnosis, as well as for disease detection in low- income developing countries.

PUBLIC HEALTH RELEVANCE: This project explores dual-mode plasmonic biosensors using bioenabled nanomaterials --- diatom biosilica, for ultra-sensitive detection of various biomolecules. Compared with existing plasmonic biosensors, our device offers exclusive advantages including ultra-high sensitivity (<1pg/mL), qualitative and quantitative detection through dual-mode spectroscopies, more robust molecule binding at the surface, as well as very low cost (<$1/chip) and eco-friendly fabrication.