Diversely positive-charged gold nanoparticles based biosensor: A label-free and sensitive tool for foodborne pathogen detection

• Published in: Food Chemistry: X 2019-09, Vol.3, p.100052-100052, Article 100052
• Main Authors: Bu, Tong, Jia, Pei, Liu, Jinghan, Liu, Yingnan, Sun, Xinyu, Zhang, Meng, Tian, Yongming, Zhang, Daohong, Wang, Jianlong, Wang, Li
• Format: Article
• Language: English
• ISSN: 2590-1575; 2590-1575
• DOI: 10.1016/j.fochx.2019.100052

• A label-free, non-paired antibodies dependent biosensor was constructed. • (+) AuNPs were employed to generate signal and capture bacteria in the new LFS. • This work possesses a desirable universality for other pathogens. Gold nanoparticles (AuNPs)-based lateral flow strip (LFS) enables a quick screening of foodborne bacteria in point-of-care (POC) diagnostics but suffers from the cumbersome labeling of antibodies and poor sensitive performance. Here, we innovated a label-free immunoassay to detect pathogenic bacteria by introducing diversely positive charges functionalized AuNPs ((+) AuNPs). The (+) AuNPs can be loaded on negatively charged bacteria via electrostatic interaction, leading to a color labeling to target bacteria. Afterward, the (+) AuNPs-bacteria complex can be specifically captured by monoclonal antibody (McAb) immobilized on test (T)-line. Under optimum conditions, the proposed LFS exhibited a lowest detectable concentration of 10 3  CFU/mL for Salmonella enteritidis ( S. enteritidis ) and could be well applied in drinking water, lettuce and pork samples. Moreover, this novel (+) AuNPs-LFS possessed a universal applicability, which could also be used for detecting Escherichia coli O157 ( E. coli O157) with a superior sensitivity (10 4  CFU/mL) and specificity.