Trident-Shaped WaveFlex Fiber-Optic Biosensor for Ochratoxin A Detection in Real Cereal Products

This article proposed a trident-shaped fiber-optic WaveFlex biosensor based on the localized surface plasmon resonance (LSPR) principle for the detection of ochratoxin A (OTA). The LSPR phenomenon can be successfully excited by coating the probe surface with gold nanoparticles (AuNPs). In order to obtain a more pronounced LSPR phenomenon, a WaveFlex-type fiber-optic sensor was fabricated using single-mode fiber (SMF), which can enhance evanescent waves (EWs) and generate a stronger evanescent field to better excite the LSPR phenomenon. Since LSPR is sensitive to the dielectric environment of the surrounding environment, multiwalled carbon nanotubes (MWCNTs) and tungsten disulfide quantum dots (WS2-QDs) are used to change the dielectric environment of the AuNPs to regulate the LSPR phenomenon to improve the sensing performance of the sensor. To evaluate the sensing performance of the sensor, tests such as repeatability, reproducibility, stability, and selectivity were conducted on the proposed sensing probe. The linear range of the sensor was 0–60 ng/mL, with a detection limit of 4.45 ng/mL. Finally, OTA detection in corn and beer showed recovery rates of 84.6%–100% and 84.5%–92.1%, respectively. The experimental results indicate that the sensor has excellent sensing performance and potential for application in real food samples.