Immunoassay of clenbuterol with bacteria as natural signal carriers for signal amplification

• DOI: 10.1016/j.snb.2019.02.108
• Publication Date: 2019-02-25T03:06:00Z
• Authors: Qiong Huang; Bingxin Zhao; Suvd-Erdene Bold; Tong Bu; Lingzhi Yan; Leina Dou; Qingfeng Yang; Jianlong Wang; Daohong Zhang
• Keywords: Clenbuterol; Horseradish peroxidase; Assay sensitivity; SIGNAL (programming language); Linear range

Abstract Many food safety hazard factors pose a great threat to human health. To mornitor these factors, development of a sensitive, reliable, and efficient detection platform is significantly important. Herein, a sensitive indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed, in which bacteria was introduced as natural signal carriers to construct probes. Through the carriers, the ratio between signal and recognition molecules was flexibly adjusted. As is known, in the competitive immunoassay, the limited number of antibodies was key to significantly improved sensitivity. By this protocol, horseradish peroxidase (HRP) was enriched on the bacterial surface to realize signal amplification, extremely reduce the applied quantity of antibody, and finally trigger intense competition between free target analytes and immobilized antigen. Clenbuterol (CL) as a model target was analyzed by the proposed biosensor system, with a linear range of 0.02–1.0 ng mL−1 and a sensitivity (expressed as IC50) of 0.16 ng mL−1. This contribution has opened up a new route to improve analytical performance of ic-ELISA and provided an application prospect in the detection of other small molecule targets.