Dual Functional Core-Shell Fluorescent Ag2S@Carbon Nanostructure for Selective Assay of E. coli O157:H7 and Bactericidal Treatment

Ning Wang; Xing Wei; An-Qi Zheng; Ting Yang; Ming-Li Chen; Jian-Hua Wang

doi:10.1021/acssensors.6b00688

Dual Functional Core-Shell Fluorescent Ag₂S@Carbon Nanostructure for Selective Assay of E. coli O157:H7 and Bactericidal Treatment

ACS Sens. 2017 Mar 24;2(3):371-378. doi: 10.1021/acssensors.6b00688. Epub 2017 Mar 8.

Authors

Ning Wang¹, Xing Wei¹, An-Qi Zheng¹, Ting Yang¹, Ming-Li Chen¹, Jian-Hua Wang¹

Affiliation

¹ Research Center for Analytical Sciences, Department of Chemistry, College of Sciences, Northeastern University , Shenyang, China , 110819.

PMID: 28723213
DOI: 10.1021/acssensors.6b00688

Abstract

A dual functional fluorescent core-shell Ag₂S@Carbon nanostructure is prepared by a hydrothermally assisted multi-amino synthesis approach with folic acid (FA), polyethylenimine (PEI), and mannoses (Mans) as carbon and nitrogen sources (FA-PEI-Mans-Ag₂S nanocomposite shortly as Ag₂S@C). The nanostructure exhibits strong fluorescent emission at λ_ex/λ_em = 340/450 nm with a quantum yield of 12.57 ± 0.52%. Ag₂S@C is bound to E. coli O157:H7 via strong interaction with the Mans moiety in Ag₂S@C with FimH proteins on the fimbriae tip in E. coli O157:H7. Fluorescence emission from Ag₂S@C/E. coli conjugate is closely related to the content of E. coli O157:H7. Thus, a novel procedure for fluorescence assay of E. coli O157:H7 is developed, offering a detection limit of 330 cfu mL^-1. Meanwhile, the Ag₂S@C nanostructure exhibits excellent antibacterial performance against E. coli O157:H7. A 99.9% sterilization rate can be readily achieved for E. coli O157:H7 at a concentration of 10⁶-10⁷ cfu mL^-1 with 3.3 or 10 μg mL^-1 of Ag₂S@C with an interaction time of 5 or 0.5 min, respectively.

Keywords: Ag2S@C; E. coli assay; antibacterial effect; core−shell nanostructure; dual-function; fluorescence.