A PSiO₂/ZnO aptamer microarray chips based on "quenching-restoration" fluorescence strategy for multiple mycotoxin...

Co-contamination and co-exposure of mycotoxins in cereals threaten human life and health. And PSiO₂/ZnO composite nanostructured substrates with signal amplification capability provide a versatile and more sensitive platform for high-throughput microarray chip detection. Therefore in this work a PSiO₂/ZnO aptamer microarray chip for the detection of multiple mycotoxins in various cereals was developed and evaluated. The entire qualitative and quantitative process of the chip was primarily accomplished through a "quenching-restoration" fluorescence strategy. On the microarray immobilized with aptamers and complementary strands forming a double-stranded DNA structure. Fluorescence resonance energy transfer (FRET) caused fluorescence quenching on the chip surface. In this detection system, mycotoxins preferentially bound to the aptamers with high specificity. Consequently, the complementary strands were displaced, eliminating the quenching effect and allowing the fluorescence on the chip surface to recover. Finally, the changes of different fluorescence values in multiple channels were utilized. Thus, high-throughput and highly specific quantitative detection and analysis of multiple toxins have been completed. The results showed that the sensitivity of the method applied to the simultaneous detection of OTA, DON and ZEN in cereals was as low as 0.0137 ng/kg, 0.0185 ng/kg and 0.2730 ng/kg, respectively. In addition, the chip combined with the improved QuEChERS method enabled the detection of toxins in various cereals with good accuracy and stability at the same time. Based on the detection principle and adjustable characteristics of the chip, and the method is expected to be applied to the high-throughput detection of other small molecules.