Cauliflower-Inspired 3D SERS Substrate for Multiple Mycotoxins Detection

Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool, but simultaneous detection of multiple targets using SERS remains a challenge. Herein, a cauliflower-inspired 3D SERS substrate with intense hot spots was prepared through sputtering Au nanoparticles (Au NPs) on the surface of polydimethylsiloxane coated anodic aluminum oxide (PDMS@AAO) complex substrate. As a result, the cauliflower-inspired 3D SERS substrate achieved the highest SERS activities at a sputtering time of 8 min. Under the optimal conditions, this SERS substrate possessed a low detection limit of 10⁻¹² M, excellent enhancement uniformity (relative standard deviation, RSD = 4.57%) and high enhancement factor (2.2 × 10⁶) for 4-mercaptobenzoic acid (4-MBA). Furthermore, the results of Raman showed that the 3D-Nanocauliflower SERS substrates could realize the simultaneous label-free detection for three mycotoxins (aflatoxin B₁, deoxynivalenol, and zearalenone) in maize for the first time. It behaved good linear relationship between the concentrations and Raman intensities of aflatoxin B₁, zearalenone, and deoxynivalenol. For the three mycotoxins, this method exhibited the limit of detection (LOD) of 1.8, 47.7, and 24.8 ng/mL (S/N = 3), respectively. The 3D-Nanocauliflower SERS substrates with dense hot spots presented remarkable SERS effect and activity, which could be act as a potential candidate for SERS substrate applied in the rapid and label-free detection.