Magnetically controlled fluorescence aptasensor for simultaneous determination of ochratoxin A and aflatoxin B1

Development of an efficient method for the simultaneous detection of two highly concerning mycotoxins, ochratoxin A (OTA) and aflatoxin B1 (AFB1), is of great significance on food safety monitoring. Herein, a magnetically controlled fluorescence aptasensor for simultaneous determination of OTA and AFB1 has been successfully developed. The working principle of the aptasensor is based on the specific aptamer-mycotoxin recognition and further leads to the partial release of two distinguishable fluorescence labels from the magnetic carriers. Through the magnetic separation, the reporter probes in the supernatant solution can be collected and converted into a sensitive fluorescence signal with dual emission peaks. This aptasensor provided a wide detection range of 2 pg mL^-1 - 5 ng mL^-1 for OTA and 5 pg mL^-1 - 10 ng mL^-1 for AFB1. The new easy-to-wash and simple-to-use approach offers a simultaneous and high selective detection with high sensitivity (limits of detection of 0.67 and 1.70 pg mL^-1 for OTA and AFB1, respectively). Remarkable accuracy (relative standard deviation < 5.6%) during the mycotoxins determination as well as excellent quantitative recoveries (95-108%) during the analysis of the spiked corn samples were also achieved. This simple aptasensing scheme provides a new avenue for high throughput screen of dual mycotoxins due to its simple manipulation, short assay times, high selectivity and sensitivity.