An antibody-free sensing strategy based on FeNPs@Pt and thiol-Michael addition: Visual detection of acrylamide in food

The core–shell FeNPs@Pt shows excellent catalytic activity and stability. • Selective detection via thiol–Michael addition without enzymes or aptamers. • The color development is rapid and convenient, taking only 150 s to complete. • The suppression–recovery mechanism amplifies the signal and enhances sensitivity. In this study, we propose an innovative Acrylamide (AA) detection platform based on platinum-coated magnetic iron nanoparticles (FeNPs@Pt). The introduction of a platinum shell not only preserves the intrinsic catalytic properties of FeNPs but also significantly enhances their structural stability and catalytic activity. Compared with traditional antibody–aptamer-based detection methods, this platform employs a thiol–Michael addition reaction combined with a nanocatalyst-mediated cascade colorimetric process. This approach overcomes key limitations of antibody–aptamer technologies, such as high cost and operational complexity, enabling rapid and low-cost detection of AA. The mechanism involves a specific Michael addition reaction between AA and 2,2′-(ethylenedioxy)diethanethiol (EDT), which mitigates the inhibitory effect of EDT on the catalytic activity of FeNPs@Pt. Subsequently, the addition of 3,3′-dimethylbenzidine (TMB) triggers a colorimetric reaction within 150 s, rendering the result visible to the naked eye. This sensing platform exhibits a linear response over the range of 1–200 μM, with a detection limit as low as 0.63 μM. Notably, the FeNPs@Pt–EDT–TMB-based colorimetric detection platform not only provides an efficient and low-cost method for acrylamide detection but also offers an innovative solution for on-site food safety monitoring, demonstrating significant application potential. Download: Download high-res image (108KB) Download: Download full-size image