An immune-scaffold relying biosensor for simultaneous detection of nitrofurazone and furazolidone

Here, to realize the simultaneous, simple, and highly sensitive detection for nitrofurazone and furazolidone, an immune-scaffold relying immunochromatographic assay was proposed. In this multi-detection immunochromatographic assay (MDICA), the immune-scaffold is composed of labeled anti-antibody IgG (Ab2) and two anti-analyte monoclonal antibodies (Abs1). A nanocomposite of MIL-101 (Cr)@AuNPs is used as the signal tag, where the unique optical property and biocompatibility of AuNPs and the protective effect of metal-organic framework can enable the nanocomposite possesses powerful signals, conjugating ability with antibodies and enhanced colloidal stability. In the immune-scaffold platform, the labeled Ab2 is the core trestle, on the one hand to exempt Ab1 from labeling requirement and offer strong detection signals, on the other hand to orient Abs1 to expose their antigen-binding sites as well as improve the identification and binding efficiency between antigen and antibody. Compared with randomly fixed antibody in the conventional probe, a 6-fold reduction of applied Ab1 amount can be achieved to produce the similar signal intensity in the immune-scaffold based method. In brief, the proposed MDICA system can effectively simplify the construction steps of MDICA, improve the Abs1 utilization efficiency, heighten analytical performances, and providing an efficient, valuable reference for the establishment of other MDICAs.