Aptamer-AuNP-conjugated carboxymethyl chitosan–functionalized graphene oxide for colorimetric identification of Salmonella typhimurium

• Published in: Mikrochimica acta (1966) 2022-11, Vol.189 (11), p.408-408, Article 408
• Main Authors: Wu, Pian, Huang, Ruixue, Chen, Cuimei, Yi, Jiecan, Kai, Tianhan, Zhan, Yujuan, Wei, Xiaoqian, Wang, Danqi, Zhang, Jingwen, Ding, Ping
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chitosan; Colorimetry; Graphene; Graphite; Microengineering; Microorganisms; Nanochemistry; Nanotechnology; Original Paper; Salmonella; Salmonella typhimurium; Van der Waals forces
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-022-05494-0

A novel aptamer-AuNP-conjugated carboxymethyl chitosan–functionalized graphene oxide (CMC/GO@Apt-Au NP) probe was for the first time developed for the determination of Salmonella typhimurium ( S. typhimurium ). Owing to the conformational change of the aptamers in the presence of S. typhimurium , the Au NPs, which were pre-adsorbed on the aptamers through van der Waals forces, were released into the solution phase and induced the color change of the solution. As a result, S. typhimurium ranging from 10 2 to 10 7  CFU/mL was successfully identified using the designed assay with a limit of detection (LOD) of 10 CFU/mL. This low detection level allowed the sensitive recognition of S. typhimurium in milk samples within 40 min without sample pretreatment, a conclusion that agreed well with the traditional plate counting method. The developed method not only provides a rapid way for the determination of S. typhimurium with simplicity and sensitivity but also shows potential universality in the quantification of other pathogenic microorganisms. Graphical abstract