Diagnose Pathogens in Drinking Water via Magnetic Surface-Enhanced Raman Scattering (SERS) Assay

Abstract

Rapid identification and diagnosis of bacteria and other microorganisms is a great challenge for drinking water safety due to the
increasing frequency of pathogenic infections. Raman spectroscopy is a non-destructive tool to characterize the biochemical
fingerprints of bacterial cells and its signal can be improved by surface-enhanced Raman scattering (SERS). Thus, Raman
scattering has a huge potential in fast diagnosis of pathogens in drinking water, with low cost and high reproducibility. In this
work, we developed a novel fast diagnosis method to detect aquatic pathogens via magnetic SERS assay. With chemical coprecipitation
synthesis and surface glucose reduction, the silver-coated magnetic nanoparticles (Ag@MNPs) had a welldeveloped
core-shell structure and high efficiency to capture bacterial cells. Ag@MNPs achieved 103 enhancement factor for
rhodamine 6G and the limit of detection was 10-9 M. The magnetic SERS assay also successfully detected various bacteria (A.
baylyi and E. coli) with high sensitivity (105 CFU/mL). This platform provided a promising and easy-operation approach for
pathogen detection for food and drinking water safety.