Charles Mann Award: Revisiting Immunoassays, Sample Preparation, and Surface-enhanced Raman Scattering

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: This presentation described the development of a surface-enhanced Rama scattering test for tuberculosis biomarkers.

Abstract Text:

Surfaced-enhanced Raman scattering (SERS) was first applied to immunoassays by T. Cotton and colleagues in 1989 [Anal. Biochem. 182, 388-398 (1989)]. This work used the resonance variant of SERS - surface-enhanced resonance Raman scattering (SERRS) - to measure thyroid stimulating hormone (TSH) in a sandwich immunoassay whereby captured TSH was tagged with anti-TSH antibodies modified with a yellow azo dye. The goal of these studies, which reached a limit of detection of ~1.5 pM, was to exploit SERRS as a basis for the development of a rapid, instrument-based immunoassay system that reduced the labor-intensive and time-consuming nature of solid-phase immunoassays. This presentation provides an update on our work in this area, which uses surface-modified gold nanoparticles as selective tags for antigens captured on a smooth gold substrate coated with a layer of capture antibodies. The discussion will focus on efforts to create a point-of-need (PON) diagnostic test for the detection of tuberculosis (TB) biomarkers from patient serum. The design of the assay, including the importance of preanalytical steps (i.e., sample digestion and concentration processes) will be discussed. The results of efforts to package key elements of the testing process into an automated microfluidics platform will also be described.