Over the last decade, miniature fiber optic spectrometers have greatly expanded the ability of Raman spectroscopy to tackle practical applications in the field, from mobile pharmaceutical ID to hazardous material assessment in remote locations. There remains a gap, however, between the typical diode array spectrometer and their more sensitive benchtop analogs. High sensitivity, cooled Raman spectrometers have the potential to narrow that gap by providing greater sensitivity, better SNR, and faster measurement times. In this paper, we'll look at the key factors in the design of high sensitivity miniature Raman spectrometers and their associated accessories, as well as the key metric for direct comparison of these systems - limit of detection. With the availability of our high sensitivity Raman systems operating at wavelengths from the UV to NIR, many applications are now becoming practical in the field, from trace level detection to analysis of complex biological samples.
We describe a compact computational spectroscopy platform optimized for molecular recognition using metal nanoparticle assays. The objective is motivated by the urgent need for low-cost, portable and high-throughput sensors for point-of-care (POC) clinical diagnostics. Nanoparticle based sensing has been successfully demonstrated for diagnosis and monitoring of infectious diseases, drug discovery, proteomics, and biological agent detection. Molecular binding on the nanoparticle surface is transuded into an optical signal by modification of the nanoparticle extinction spectrum (via a shift in Localized Surface Plasmon Resonance) or by modification of the molecular scattering spectrum (via Surface Enhanced Raman Scattering).
Translating a nanoparticle -based molecular recognition system into a functional miniature hand-held biosensor requires spectrometer designs optimized to large area nanoparticle assays and integrated spectral filtering to improve the signal specificity. Large population sampling with small population sensitivity is essential to highly sensitive nanoparticle assay analysis.
We describe a multimodal multiplex spectroscopy (MMS) platform that samples the spectral response of up to 106 populations of 10-100 nanoparticles in parallel. The advantages of MMS approach include: extremely high signal throughput due to its large aperture and high resolution with small form factor. We will demonstrate a nanoparticle biosensor platform based on MMS. Ultimately, a fully integrated functional miniature nanoparticle based biosensor for real time disease diagnosis in whole blood assays can be realized.
Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution.