A novel electrochemiluminescence aptasensor using Ti3C2@AuNRs-Ru for ultra-sensitive detection of T-2 toxin

Abstract

T-2 toxin is widely found in nature and also contaminates field crops and grain storage, posing a potential threat to human health. In this study, an ultra-sensitive electrochemiluminescence (ECL) aptasensor has been developed for the detection of T-2 toxin using Ti3C2 MXene-based nanomaterials functionalized with gold nanorods (AuNRs) and Ru(bpy)32+ (Ti3C2@AuNRs-Ru) as the luminescent indicator. Specifically, gold nanorods are grown in situ on the surface of Ti3C2 MXene, and Ru(bpy)32+ is loaded onto Ti3C2@AuNRs via electrostatic force to form the Ti3C2@AuNRs-Ru luminescent probe, which is then modified on the electrode surface. The aptamer of T-2 toxin is connected to the electrode surface through Au-S bonds, and then the capture chain (cDNA) with a quenching probe of ferrocene is introduced to the system. Ferrocene can quench the luminescence of the probe, reducing the ECL signal. In the presence of T-2 toxin, it binds to the aptamer with higher affinity, so the quenching probe is competed down, resulting in the recovery of the ECL signal. The increase in ECL signal is linearly correlated with the logarithm of T-2 toxin concentration, with the detection range of 50 fg/mL to 50 ng/mL and a detection limit of 6.44 fg/mL. This strategy utilizes the high catalytic activity and excellent conductivity of MXene, improving the sensitivity significantly. The proposed sensor has been successfully applied for the detection of actual samples and provides a new strategy for the detection of hazardous pollutants.