A label-free, direct and noncompetitive FRET immunoassay for ochratoxin A based on intrinsic fluorescence of an antigen and antibody complex

A label-free, direct and noncompetitive homogeneous immunoassay, in which ochratoxin A (OTA) coupled with the anti-OTA antibody participates in fluorescence resonance energy transfer (FRET), was developed for the detection of OTA with great specificity and a detection limit of 1 ng mL(-1).