title: Heat shock mediated labelling of Pseudomonas aeruginosa with quantum dots.
abstract: Biocompatible nanoparticles are good candidates to label bacteria for imaging and diagnosis purposes. A high labeling efficiency reduces the concentration of nanoparticles required for labeling and allows the labeled bacteria to be tracked for longer periods. This report explores the optimal labeling strategy for Pseudomonas aeruginosa, a common gram-negative opportunistic pathogen, with quantum dots. Three strategies including direct incubation, calcium chloride treatment, and heat shock are compared and the labeling efficiency is assessed through fluorescence microscopy and flow cytometry analysis. Of the three, heat shock is finally selected due to its comparable labeling efficiency and simplicity. Through the assay of the respiration rate of bacteria together with morphology analysis, the heat shock process does not show any negative effect over the cells activity even at sub-toxic concentrations.
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore.
authors.forename: Natasha
authors.initials: N
authors.lastname: Kumar
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore.
authors.forename: Christian
authors.initials: C
authors.lastname: Wiraja
authors.affiliation: Singapore Centre for Environmental Life Science Engineering, 60 Nanyang Drive, Singapore.
authors.forename: Kannan
authors.initials: K
authors.lastname: Palanisamy
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore; Singapore Centre for Environmental Life Science Engineering, 60 Nanyang Drive, Singapore. Electronic address: emarsili@ntu.edu.sg.
authors.forename: Enrico
authors.initials: E
authors.lastname: Marsili
authors.affiliation: School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore; NTU-Northwestern Institute for Nanomedicine, Nanyang Technological University, 50 Nanyang Avenue, Singapore. Electronic address: CJXu@ntu.edu.sg.
authors.forename: Chenjie
authors.initials: C
authors.lastname: Xu
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D002122:Calcium Chloride / Q000494:pharmacology; D058948:Cell Tracking / Q000379:methods*; D005434:Flow Cytometry; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D050296:Microbial Viability / Q000187:drug effects; D008856:Microscopy, Fluorescence; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry; D013194:Staining and Labeling / Q000379:methods*; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D017967:Zinc Compounds; C058667:cadmium selenide; D002122:Calcium Chloride; C044696:zinc selenide
keywords: Bacteria labeling; Heat shock; Pseudomonas aeruginosa; Quantum dots