Developing a Simple Immunochromatography Assay for Clenbuterol with Sensitivity by One-Step Staining

An innovative lateral flow competition immunoassay (LFCIA) for detecting clenbuterol (CL) was developed by employing the advantages of the coomassie brilliant blue (CBB) staining method. An antibody stained by CBB was used both as a recognition reagent and as a chromogenic probe, enabling the simple but sensitive LFCIA of CL. The CBB-based LFCIA exhibited sensitivity for CL with a detection limit of 2 ng mL^-1. Furthermore, this strategy was preliminarily verified by screening for CL in milk, pork tenderloin, and swine liver with recoveries ranging from 81 to 102%. Compared with conventional LFCIAs, the use of CBB as a signal label not only avoided the complicated material synthesis and surface modification process but also simplified the cross-linking with antibodies, meanwhile reducing the steric hindrance and increasing the possibility of immune recognition reactions, which was propitious for the effective utilization of antibodies. Taking advantages of the simplicity, rapidity, and cost-effectiveness, the CBB-based LFCIA may have potential for on-demand monitoring of general harmful small molecules by changing the kind of the staining antibody.