3D plasmonic SERS aptasensor for rapid detection of aflatoxin B1 combined with Au@Ag bimetallic nanostars and Fe3O4@MoS2 magnetic nanoflowers

As a virulent metabolite, aflatoxin B 1 (AFB 1 ) presented in various cereal grain is tightly implicated in severe human diseases. In this study, 3D plasmonic nanohybirds of Raman molecule 4-mercaptobenzoic acid (4-MBA)-embedded and AFB 1 aptamer-modified bimetallic nanostars as SERS probes bound to magnetic nanoflowers were fabricated and demonstrated as a high-performance SERS-active aptasensor to quantitatively analyze AFB 1 . Bimetallic Au@Ag SERS plasmonic nanoprobes with enhanced properties were capable of enhancing discriminative Raman peaks of 4-MBA. Then, the integration of iron tetroxide nanoparticles (Fe 3 O 4 NPs) and molybdenum disulfide nanosheets (MoS 2 NShs) with huge specific surface area constituted stable 3D Fe 3 O 4 @MoS 2 plasmonic nanoflowers, facilitating the bind of numerous aptamer-based SERS probes via the non-covalent interaction between MoS 2 NShs and aptamer, which were ideal candidates for SERS-active substrates. Additionally, Fe 3 O 4 NPs as magnetic core endowed 3D nanocomposites with specific magnetic separation characteristic that caused the collected SERS hotspots to exhibit superior signal response, and further strengthening the sensitivity in a complex food matrix. Aptamer-target AFB 1 specific recognition triggered linearly diminished 4-MBA signal intensity (I 4-MBA ) on the substrate to achieve a low detection limit of 58.9 pg/mL. Furthermore, the sensor has the potential to be a promising monitoring tool for other trace contaminants.