Imaging sensor array coupled with dual-signal amplification strategy for ultrasensitive chemiluminescence immunoassay...

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 B₁ 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 μL 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.