A sensitive WS2 nanosheet sensing platform based on chemiluminescence resonance energy transfer for the detection of ochratoxin A

In this article, we report a tungsten disulphide (WS2) nanosheet sensing platform based on chemiluminescence resonance energy transfer (CRET) for light on detection of ochratoxin A (OTA). The CRET system involves OTA aptamer-12-mer linker-DNAzyme, phosphate-DNA, lambda exonuclease (λexo), hemin, H2O2, luminol and a WS2 nanosheet. Based on the change in chemiluminescence intensity resulting from the OTA aptamer-12-mer linker-G-Quadruplexes/Hemin DNAzymes affinity for or desorption from the WS2 nanosheet surface in the presence and absence of OTA, an ultra-sensitive CRET-based sensor system is proposed, in which the OTA aptamer-12-mer linker-G-Quadruplexes/Hemin DNAzymes–H2O2–luminol and WS2 nanosheets act as CRET donors and acceptors, respectively. Various factors affecting the detection of OTA, including the incubation time of the OTA aptamer-12 mer linker-G-Quadruplexes/Hemin DNAzyme and WS2 nanosheet, the amount of λexo, concentrations of the WS2 nanosheet, luminol and H2O2, and pH value of the chemiluminescence reaction solution were investigated in detail. Under the optimal experimental conditions, the relative luminesecence intensity of the sensing system exhibited a good linear correlation with the OTA concentration in the range of 1.0–10.0 ng mL–1 with a LOD of 0.13 ng mL–1. The proposed CRET-based sensing system also exhibited excellent recoveries of 85.7–93.0% in rice samples and showed good application prospects for the analysis and detection of OTA, which is also easily extended to assay other biomolecules by simply changing the recognition sequence with the substrate aptamer.