A novel colorimetric sensor using aptamers to enhance peroxidase-like property of gold nanoclusters for detection of Escherichia coli O157:H7 in milk. (May 2022)

• Record Type: Journal Article
• Authors: Song, Yang; Wang, Lihan; Zhao, Jiayuan; Li, Hongxuan; Yang, Xinyan; Fu, Shiqian; Qin, Xue; Chen, Qing; Jiang, Yujun; Man, Chaoxin
• Is Part Of: International dairy journal. Volume 128(2022)
• Publication Date: 2022-05
• Subjects: Dairying -- Periodicals; Industrie laitière -- Périodiques; Electronic journals; 338.1762142
• DOI: 10.1016/j.idairyj.2022.105318
• Languages: English
• ISSNs: 0958-6946

Abstract

Abstract: Escherichia coli O157:H7 is a pathogenic foodborne bacterium of public health concern. A simple, rapid, and environmentally friendly method was developed to synthesise papain-modified gold nanoclusters (papain@AuNCs). Following this, aptamers-modified papain@AuNCs (aptamers@papain@AuNCs) were constructed by reacting Au–S covalent bonds between thiolated aptamers and the papain@AuNCs, enhancing the peroxidase activity. E. coli O157:H7 could be captured through the aptamer@papain@AuNCs, significantly improving the catalytic activity toward the peroxidase substrate 3, 3′, 5, 5′-tetramethylbenzidine, and the blue products could be generated. Papain was used for the first time as a template for the synthesis of AuNCs of peroxidase-like activity for detection. The quantitative detection for E. coli O157:H7 was 39 cfu mL −1 in pure culture. The detection limit of E. coli O157:H7 was 5.6 × 10 2, 5 × 10 2 and 4.9 × 10 2 cfu mL −1 in ultra-high temperature sterilised, pasteurised, and raw milk samples, respectively, after 2 h pre-incubation, indicating that the developed sensor has potential for pathogen detection in foods.