"Stick-and-Sense": a flexible paper SERS tape for rapid, selective and high - sensitivity food and water pathogen...

Rapid detection of foodborne pathogens is vital for public health, yet conventional methods for identifying Escherichia coli are slow, costly, and laboratory dependent. We present a simple paper-based SERS sensor fabricated by coating commercial adhesive tape with self-assembled gold nanoparticles. The platform enables label-free discrimination of E. coli, Enterococcus, and Citrobacter in water using their characteristic Raman fingerprints and principal component analysis, achieving a calculated E. coli detection limit of 26 CFU/mL. To operate in complex food matrices, the substrate was functionalized with an anti-E. coli antibody, enabling selective detection in commercial milk at concentrations as low as 25 CFU/mL, thereby experimentally validating the sensor performance in a real food matrix. Compared to existing flexible SERS substrates, our dual-mode approach combining label-free identification in aqueous media with targeted immunodetection in food offers competitive sensitivity, straightforward fabrication, and an enhancement factor of ≈10⁷. These results highlight the potential of this paper-based SERS sensor as an accessible tool for rapid, on-site microbial monitoring in both water and food safety applications.