Development Of Colloidal Gold-Based Immunochromatographic Strips For The Detection Of Food Allergen

Three kinds of colloidal gold immunochromatograph assay (GICA) for the detection of ovotransferrin from egg, almond allergen protein, and peanut allergen protein were developed. The method is simple, rapid, economic, sensitive, specific, and results in detection with the naked eye and no cross-activity with other kinds of allergen. This study first reported a GICA method for the simultaneous determination of almond and peanut in foods and it can save more time to reducing the workload in the future.Developing ovotransferrin colloidal gold immunechromatography test strip detection method, the partical size of colloidal gold is 20 nm to labeled antibody; the best pH value of colloidal gold label antibody is 8.5, the amount of antibody is 25 μg/mL; capture antibody concentration is 1.3 mg/mL; second antibody and the nano-colloidal gold-antibody probe was diluted to 80 and 5 fold; choose Millipore HF135s models of nitrocellulose membrane as solid phase carrier; the article diluent selection pH 8.5 PBST buffer; 0.01% casein diluted with PBS as block processing fluid and blocking 1 h to the NC membrane; colloidal gold treated with 0.5% Tween-20. This method can be measured for ovotransferrin standard of detection limit is 15 ng/mL.Developing almond allergen GICA test strip detection method, the best pH value of colloidal gold label antibodies is 9.0, the amount of antibody is 36 μg/mL; capture antibody concentration is 1.5 mg/mL; second antibody and the nano-colloidal gold-antibody probe was diluted to 200 and 6 fold; 2% BSA diluted with PBS as block processing fluid and blocking 1 h to the NC membrane; other working conditions with ovotransferrin GICA test strips in the same way. This method can be measured for almond protein and standard of detection limit is 100 ng/mL.Developing peanut allergen GICA test strip detection method, the best pH value of colloidal gold label antibodies is 9.0, the amount of antibody is 25 μg/mL; capture antibody concentration is 0.5 mg/mL; second antibody and the nano-colloidal gold-antibody probe was diluted to 100 and 5 fold; other working conditions with another two kinds of GICA test strips, and detection limit is 25 ng/mL and without cross reaction.An immunochromatographic strip test for the simultaneous detection of almond and peanut allergen protein was developed, visual limit of almond allergen is 100 ng/mL and visual limit of peanut allergen is 25 ng/mL, which with commercial kits compared with a lower detection limit. BSA amount for almond and peanut antibody respectly 40 μL,30 μL to block colloidal gold antibody. Simultaneous detection of almond, peanut can save more time and play better prevention and warning.