A label-free aptasensor for ochratoxin a detection with signal amplification strategies on ultrathin micron-sized 2D MOF sheets

The increasing requirement for highly sensitive sensors has promoted the development of new functional nanomaterials and various signal amplification strategies. Due to 2 dimensional (2D) materials’ excellent features of large surface areas, structural diversity, and abundant exposed accessible active sites, 2D MOF nanosheets exhibit potential applications in biosensing. Here, an ultrathin micron-sized MOF sheets with good dispersibility and high stability were prepared. Furthermore, a novel label-free aptasensor for ochratoxin A (OTA) detection had been developed based on 2D MOF nanosheets. This sensing signal was amplified by signal amplification strategies containing DNA walker machine, enrichment of Mb signal and nanomaterials of 2D MOF nanosheets and Ag NPs. With the help of these signal amplification strategies, the detection of OTA was reached with a low detection limit (0.08 fg mL −1 ) and a wide linear rage (0.10 fg mL −1 – 1 μg mL −1 ). Additionally, the aptasensor exhibits excellent OTA sensing performances, for example, good stability, outstanding selectivity, excellent repeatability, and regenerability.