Ultra-sensitive deoxynivalenol detection via SPR-enhanced ellipsometry on an electrochemically deposited nanofilm.

A highly sensitive SPRe-TIRE (Surface Plasmon Resonance-enhanced Total Internal Reflection Ellipsometry) aptasensor was developed for label-free detection of deoxynivalenol using the DN-2 aptamer as the specific recognition element. A mercaptophenyl monolayer was electrochemically grafted onto an SF-10/Au substrate via diazonium reduction, and characterized by ellipsometry and X-ray photoelectron spectroscopy. Gold nanoparticles were then self-assembled to enhance plasmonic coupling, followed by thiol-modified DN-2 aptamer immobilization. The aptasensor exhibited a wide semi-log linear range from 0.01 to 1000 ng/mL with a detection limit of 0.005 ng/mL. Selectivity tests against zearalenone, patulin, aflatoxin B1, and ochratoxin A confirmed high specificity, while recoveries from spiked wheat and corn flour samples (95.6-104.6%) correlated well with ELISA results. Compared with conventional immunoassays requiring 90-120 min, the proposed system achieved complete analysis within approximately 30 min. The developed SPRe-TIRE aptasensor provides a rapid, reliable, and ultrasensitive platform for real-time mycotoxin monitoring in food safety applications.