Nanobody-alkaline phosphatase fusion-mediated phosphate-triggered fluorescence immunoassay for ochratoxin a detection

Ochratoxin A (OTA) is a kind of mycotoxin that seriously harms the health of humans and animals. In this study, a nanobody-alkaline phosphatase fusion-mediated phosphate-triggered fluorescence immunoassay (Nb-AP-mediated PT-FIA) was developed for detecting OTA. Based on the constructed phosphate-triggered fluorescence sensing system for Nb-AP and the optimal working conditions, the Nb-AP-mediated PT-FIA has a half maximal inhibition concentration (IC50) of 0.46 ng/mL, a limit of detection (IC10) of 0.12 ng/mL, and a linear range (IC20-80) of 0.2-1.26 ng/mL, respectively. The recovery experiment indicated acceptable accuracy and precision of the Nb-AP-mediated PT-FIA, and the results were validated by high performance liquid chromatography with fluorescence detector. Thus this proposed method is applicable to sensitive, rapid, and low-cost detection of OTA and other toxic analytes with low molecular weight in food and environment.