A dual-probe SERS aptasensor for ultrasensitive detection of acrylamide in food

This study developed an aptamer sensor based on surface-enhanced Raman scattering (SERS) for the highly sensitive and selective detection of acrylamide (AAm) in food. Au@4MBA@Ag core-shell nanoparticles were synthesized and functionalized with thiol-modified AAm aptamers (Apt) to serve as signal probes. Meanwhile, Fe₃O₄@PEI@Ag magnetic nanoparticles were prepared and modified with complementary DNA (cDNA) to act as capture probes. The two probes were combined through Apt-cDNA hybridization to form a complete SERS sensing system. The structure and surface properties of Fe₃O₄@PEI@Ag were systematically characterized using various characterization methods, and its SERS enhancement performance was validated using Rhodamine 6G (R6G). Similarly, Au@4MBA@Ag was characterized to confirm its excellent SERS activity and reproducibility. The constructed SERS aptamer sensor achieves a detection limit as low as 3.26 × 10^-10 M for AAm, and the aptamer sensor shows no response to structural analogues (such as acrylic acid and methacrylamide), demonstrating excellent specificity. In actual sample testing, the recovery rate was 90%-110%, highly consistent with HPLC detection results (recovery rate of 90%-110%). Therefore, this sensor offers advantages such as ease of operation, rapid detection, and strong resistance to interference, providing a reliable new method for trace detection of AAm in food.