Label-free localized surface plasmon resonance (LSPR) biosensor, based on Au-Ag NPs embedded in TiO2 matrix, for detection of Ochratoxin-A (OTA) in wine

Ochratoxin-A (OTA) is a widespread foodstuff contaminant with potential carcinogenic effects. Innovative sensing technologies that allow on-site and sensitive food screening can have a significant impact on food and environment safety. A novel and quantitative label-free LSPR-based biosensor was specifically designed for OTA detection, employing a portable LSPR spectroscopy sensing system for efficient on-site and cost-effective analysis. This biosensor is comprised of monoclonal anti-OTA antibodies immobilized on the surface of sputtered Au-Ag nanoparticles embedded in a TiO₂ matrix. Under optimized conditions, the LSPR-based biosensor demonstrated a linear dynamic response from 0.05 to 2 ng mL^-1, with an estimated limit of detection at 7 pg mL^-1, using 55 μL of sample, outperforming commercial ELISA technique in relevant bioanalytical parameters. Sensitivity in OTA detection is crucial because it ensures the accurate identification of low concentrations, which is essential for preventing health risks associated to cumulative ingestion of contaminated food products. The robustness and feasibility of the presented LSPR-based biosensing was tested using spiked white wine, exhibiting a satisfactory recovery of 93 %-113 %, confirming its efficacy in a complex matrix.