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SERS Biosensors

Surface-enhanced Raman Scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. SERS-based bioassays demonstrate high sensitivity, robustness, efficiency, and point-of-care testing capability compared to conventional technologies such as ELISA and PCR. Our lab is currently working to adapt this technology to detect SARS-CoV-2, the virus responsible for COVID-19.


cartoon of GNP + MNP Raman complex

 Colloidal Assays

In the SERS-based immunoassay, biosensors labeled with different Raman dyes have characteristic spectral peaks that enable the definitive detection of multiple analytes. Target antigens are detected by capture with silica-encapsulated gold nanotags and magnetic nanoparticles conjugated with polyclonal antibodies. The magnetic pull-down results in aggregation of the immunocomplexes and the silica-encapsulated nanotags provide distinct spectra corresponding to each antigen captured in multiplex detection.

handheld raman

Robust Diagnostics

Current work aims to create a SERS-based assay that doesn't require trained personnel or long turnaround times. By using hand-held equipment and eliminating washing and incubation steps, our ultimate goal is to develop an assay that allows highly sensitive detection of a target analyte for point-of-care applications. Whether the testing technology is used in rural areas for cattle brucellosis testing or on-site at airports for human COVID-19 testing, SERS-based bioassays offer a user-friendly way of gathering rapid results.

red and orange Raman spectra

Highly Sensitive Detection

Previous work published in our lab has demonstrated simultaneous femtogram-level detection limits for two antigens with one single SERS-based immunoassay as well as picogram-level detection limits for three antigens. Target analytes include Bovine Herpes Virus, West Nile Virus, Rift Valley Fever Virus, and plague bacteria.

Contact Us

Patrick Johnson

Department of Chemical Engineering

1000 E. University Ave.

Laramie, WY 82071

Phone: (307) 766-6524


1000 E. University Ave. Laramie, WY 82071
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