Imaging sensor array coupled with dual-signal amplification strategy for ultrasensitive chemiluminescence immunoassay of multiple mycotoxins

A novel chemiluminescence (CL) immunosensor array in combination with a dual-signal amplification strategy was developed for rapid and ultrasensitive detection of multiple mycotoxins in herbal medicine. The multi-component immunosensor array was constructed by immobilizing different bovine serum albumin combined mycotoxins on the corresponding sites of the aldehyde-modified glass slide. After competitive immunoreactions, CL triggered by signal tags captured on all the sensing sites can be collected by a charge-coupled device simultaneously for joint detection of several mycotoxins. By assembling a high ratio of horseradish peroxidase (HRP) and IgG on the surface of gold nanoparticles (AuNPs), a biofunctionalized complex named HRP@AuNP-IgG was prepared and served as the primary signal tag to amplify the CL signals. Then, by introducing tyramine signal amplification (TSA) technique, a new round of HRP could deposit around the HRP@AuNP-IgG, which brought the secondary CL amplification. As a proof of concept, the CL imaging sensor array was applied to the trace detection of citrinin, aflatoxin B-1 and ochratoxins A in red yeast rice samples. Under optimal conditions, it exhibited wide linear ranges over 4 orders of magnitude and much lower limits of detection than previous works. Owing to the excellent sensitivity (50-57-fold signal amplification and detection limits down to sub-pM level), acceptable throughput (20 tests h(-1)), small amounts of reagents (3.5 mu L for each test), simple sample pretreatment (no necessary of separation for 3 mycotoxins), high selectivity, acceptable stability and accuracy, the proposed sensing platform showed broad prospects in the joint monitoring of low-abundant mycotoxins and safety evaluation of herbal medicines.

Automated summary

A novel CL immunosensor array combined with a dual-signal amplification strategy was developed for rapid and ultrasensitive detection of multiple mycotoxins in herbal medicine. By immobilizing different proteins on different sensing sites, joint detection of several mycotoxins was achieved.