Rainbow latex microspheres lateral flow immunoassay with smartphone-based device for simultaneous detection of three mycotoxins in cereals.

The coexistent pollution of multiple mycotoxins displays a synergistic toxicity effect that significantly threatens human health. Therefore, it is essential to establish a rapid detection method for multi-mycotoxins in food. In this study, red, green, and blue latex microspheres (LMs) were applied as the aflatoxin B1 (AFB1), T-2 toxins (T-2), and zearalenone (ZEN) antibodies labeled tracer, respectively. Based on the principle of spatial resolution, a rainbow "traffic light" pattern latex microspheres lateral flow immunoassay (LMs-LFIA) integrated with a portable and user-friendly smartphone-based device was first developed to detect three kinds of mycotoxins simultaneously. The cut-off values of the method for AFB1/T-2/ZEN in cereals were 1/15/40 µg kg-1, the limits of detection were 0.04/0.40/1.21 µg kg-1, respectively. The recoveries ranged from 82.1% to 107.5%, with the coefficient of variation from 3.0% to 8.1%. A parallel analysis in 26 naturally contaminated cereal samples was confirmed by commercial ELISA kits; the results showed a good correlation (R2＞0.99), indicating the practical reliability of the rainbow LMs-LFIA. This method provided a visually enjoyable, portable, and sensitive detection mode for multi-target detection of mycotoxins or other small molecule hazard factors in food.

An enhanced immunochromatography assay based on colloidal gold-decorated polydopamine for rapid and sensitive determination of gentamicin in animal-derived food.

In this study, an enhancing immunochromatography assay (ICA) based on colloidal gold-decorated polydopamine (CG@PDA) was firstly developed for gentamicin in milk, muscle, liver and kidney simultaneously. CG@PDA was synthesized by one-pot method with better signal intensity, colloidal stability, and antibody coupling efficiency than traditional colloidal gold. The detection limit of the developed ICA was about 1.50 µg/kg for the four animal-derived food, which was up to 92-fold more sensitive than the reported ICA based on colloidal gold. The recovery rates were ranged from 86.0% to 114.0% with coefficient of variation between 1.6% and 13.1%. Parallel analysis of 40 samples by commercial ELISA kits was confirmed the reliability. Our research indicated that polydopamine decorated can chemically modify the surface of colloidal gold and can thus remarkably improve the detection performances of ICA.

Immunochromatographic assays based on three kinds of nanoparticles for the rapid and highly sensitive detection of tylosin and tilmicosin in eggs.

Three kinds of immunochromatographic assays (ICAs) are proposed for the highly sensitive and rapid determination  of tylosin (TYL) and tilmicosin (TIM) in eggs based on colloidal gold (CG), latex microsphere (LM), and time-resolved fluorescent microsphere (TRFM). Three types of ICAs could tolerate the egg matrix via simple sample pretreatment and demonstrated high sensitivity for TYL and TIM with cut-off values of 6/6/3 µg/kg and 14/14/6 µg/kg, respectively. Furthermore, in a single-blind parallel study 20 egg samples were analyzed  by the three developed ICAs and confirmed by LC-MS/MS. The  results showed good consistency, and there were no false positive and false negative results in our three ICAs. Consequently, the proposed three ICAs offered rapid, highly sensitive, reliable, and selectable testing platforms for screening veterinary medicine or other small molecule contaminants.