title: Direct and rapid quantum dots labelling of Escherichia coli cells.
abstract: Here, we supplied a direct and rapid quantum dots labelling method of bacterial cells in food, water and environmental contaminations. Outer layers of Escherichia coli cells prevent cells from direct interactions with molecules and objects such as quantum dots. Permeabilization treatment of E. coli cells may facilitate macromolecules penetrate cell walls and improve internal bacterial quantum dots (QDs) labelling. In this work, we investigated direct internal QDs labelling of E. coli cells permeabilized using three methods including chloroform-SDS treatment, lysozyme-EDTA treatment and osmotic shock treatment. Effects of permeabilization were analysed by scanning electronic microscopy and measuring activity of alkaline phosphatase (PhoA) released from periplasm. Internal bacterial QDs labelling was monitored by flow cytometry and fluorescent microscopy. After chloroform-SDS or lysozyme-EDTA treatment, cells could be directly labelled with QDs. No interaction was observed between osmotic shock treated cells and QDs. The mechanism of cell permeabilization explaining different labelling efficiency has been established. The QDs labelling approach presented in this work provides a simple, rapid and sensitive detection method for multiple purpose bacterial analysis in combination with biological techniques.
authors.affiliation: Laboratory of Living Materials at State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, Hubei, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Hao
authors.initials: H
authors.lastname: Xie
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.forename: Jian-Kun
authors.initials: JK
authors.lastname: Zhang
authors.forename: Bao-Lian
authors.initials: BL
authors.lastname: Su
mesh_terms: D001431:Bacteriological Techniques; D004785:Environmental Pollutants; D004926:Escherichia coli / Q000166:cytology* / Q000302:isolation & purification; D005506:Food Contamination; D045663:Quantum Dots; D013194:Staining and Labeling
chemical_list: D004785:Environmental Pollutants