Environmental-friendly gold nanoparticle immunochromatographic assay for ochratoxin A based on biosynthetic mimetic mycotoxin-conjugates

Ochratoxin A (OTA) is a possibly carcinogenic mycotoxin which is one of the most abundant food contaminants. It can be normally monitored and detected by immunochromatographic assays (ICG) which have a good sensitivity and specificity and easy to operate. However, the development of normal ICG is based on traditional OTA-conjugates or chemosynthetic mimotope peptides, which are very high-cost reagents with a detrimental effect on the environment and operators. This study takes advantage of both biosynthetic mimetic OTA-conjugates and a convenient IGG to develop a novel environmental-friendly and low-cost ICG for the rapid detection of OTA. Qualitatively, the visual cut-off level of the developed ICG for OTA was 0.8 ng/ml, which is 10-fold more sensitive than the chemosynthetic mimotope peptide based ICG, while there is no cross-reaction with other mycotoxins. The assay takes only 15 min to acquire results visible to the naked eye. Quantitatively, the half inhibition concentration of the ICG setup with mimetic OTA-conjugates was 0.187 ng/ml, with a linear range of 0.015 to 0.5 ng/ml. These results demonstrate the potential to adapt the method for detecting other toxic mycotoxins.