Bifunctional bovine serum albumin modification driven sensitivity-enhanced lateral flow immunoassay for small molecule hazards monitoring in food

Traditional lateral flow immunoassays (TLFIAs) are valued for their simplicity, speed, and user-friendliness. However, the specificity of conventional test strips often necessitates large quantities of antigen-protein conjugates for target detection, which can be resource-intensive. Here, we present a strategy aimed at enhancing the universality of test strips while reducing the consumption of antigen-protein conjugates, without compromising sensitivity. By coating streptavidin on the test line and employing bifunctional antigen-protein conjugates (competitor to target and immunoprobe linker), the test strip was thus served as a universal module. We developed three universal lateral flow immunoassays (ULFIAs) for the detection of aflatoxin B1 (AFB1), carbendazim (CBZ), and enrofloxacin (ENR). Compared to traditional methods based on the same aggregation-induced emission fluorescent microspheres, the proposed ULFIAs demonstrated a significant increase in sensitivity, with enhancements of 11.0-fold for AFB1, 10.9-fold for CBZ, and 4.1-fold for ENR. Additionally, this approach substantially reduced the consumption of antigen-protein conjugates by 19.1-fold, 40.9-fold, and 23.8-fold, respectively, thereby promoting greener detection methods. This bifunctional antigen conjugate strategy offers a promising pathway for the sensitive detection of small molecule hazards.