Simultaneous detection of multiple food allergens using high signal-to-background SERS probes

Avoiding exposure to food allergens remains the most reliable way to protect allergic individuals. Therefore, it is essential to develop selective, sensitive, and rapid methods for detecting food allergens. Herein, we introduce a novel SERS-based sandwich immunoassay that utilizes three distinct types of SERS detection probes: Ag@CA NPs, Ag_Au@PB NPs, and Ag@MB NPs, along with magnetic capture probes, to simultaneously detect almond, lactoglobulin, and gliadin allergens. These SERS probes generate unique Raman peaks at 1987 cm^-1, 2151 cm^-1, and 2223 cm^-1 in the Raman-silent region (1800-2800 cm^-1), effectively avoiding interference from the Raman-fingerprint region (400-1800 cm^-1) of potential food matrix substrates. This design ensures high signal-to-background ratios and detection accuracy, achieving limits of detection (LODs) of 7.4 pg/mL for almonds, 66 pg/mL for lactoglobulin, and 0.36 pg/mL for gliadin, with corresponding recoveries ranging from 83.7 % to 118.8 %, 98.9 % to 112.2 %, and 91.9 % to 109.5 %, respectively, demonstrating satisfactory analytical performance.