Surface Enhanced Raman Bbiosensors for Biomedical Applications

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Raman spectroscopy is a powerful tool for measuring vibrational quanta of molecules, wherein the resultant spectra provides unique chemical fingerprint. In complex biomedical matrices with thousands of different molecules, vibrational spectroscopy can be used to differentiate between biochemically distinct samples. Furthermore, the intensity of the Raman bands associated with a certain molecule are proportional to its concentration, thus allowing for simultaneous quantification. The major limitation of Raman spectroscopy is its weak signal, less than 1 in 107 incident photons are Raman scattered. Our group's overarching research goal is to create a compact, rapid, and highly sensitive point-of-care diagnostic platform based on the applicant's hollow-core photonic crystal fiber (HC-PCF) Raman system. This vision is supported by three complimentary objectives: 1.Functional nanoparticle development which include a) creating families of functionalized metal nanoparticles for surface enhanced Raman scattering that are amenable to specific sensing of clinically relevant organisms or molecules, and b) developing nanoparticles which provide simultaneous magnetic enrichment, biorecognition, and local surface plasmon resonance enhancement. These two objectives further two distinct surface enhanced Raman scattering methodologies; direct surface enhanced Raman scattering detection of analytes based on intrinsic in-situ spectral characteristics, and surface enhanced Raman scattering detection based on analyte isolated by biorecognition. 2.Advance the machine learning techniques used to process Raman spectra, improve machine learning models, extract features for biochemical analyses, and expedite model generation. 3.Miniaturization of Raman system to deploy a point-of-care spectral diagnostic system. The footprint of the conventional free-space spectrometer as well as the fluidic components that fill the HC-PCF must be reduced. To achieve this, bulk mechanical parts will be replaced by microfluidic equivalents, and similarly, free-space optics will be replaced by integrated optical components using metamaterials. This research program will further our collective knowledge on nanophotonics and nanomaterials and will lead to several advances in the fields of biomedical engineering and photonics. One of our principal aims is the development of devices for inherently multiplexed rapid spectral detection of diseases/ infections. Successful implementation of such devices will lead to faster diagnostic turnaround times, prompt administration of treatment, and better clinical outcomes. Fundamental scientific knowledge on the properties and synthesis of metal nanoparticles, the nanophotonic behavior of metamaterials, and the vibrational spectra of biological materials will also be gained.