title: Quantum dot-based assay for Cu(2+) quantification in bacterial cell culture.
abstract: A simple and sensitive method for quantification of nanomolar copper with a detection limit of 1.2×10(-10)M and a linear range from 10(-9) to 10(-8)M is reported. For the most useful analytical concentration of quantum dots, 1160μg/ml, a 1/Ksv value of 11μM Cu(2+) was determined. The method is based on the interaction of Cu(2+) with glutathione-capped CdTe quantum dots (CdTe-GSH QDs) synthesized by a simple and economic biomimetic method. Green CdTe-GSH QDs displayed the best performance in copper quantification when QDs of different sizes/colors were tested. Cu(2+) quantification is highly selective given that no significant interference of QDs with 19 ions was observed. No significant effects on Cu(2+) quantification were determined when different reaction matrices such as distilled water, tap water, and different bacterial growth media were tested. The method was used to determine copper uptake kinetics on Escherichia coli cultures. QD-based quantification of copper on bacterial supernatants was compared with atomic absorption spectroscopy as a means of confirming the accuracy of the reported method. The mechanism of Cu(2+)-mediated QD fluorescence quenching was associated with nanoparticle decomposition.
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile; Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380492, Chile.
authors.forename: V
authors.initials: V
authors.lastname: Durán-Toro
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile; Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380492, Chile.
authors.forename: A
authors.initials: A
authors.lastname: Gran-Scheuch
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile; Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380492, Chile.
authors.forename: N
authors.initials: N
authors.lastname: Órdenes-Aenishanslins
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile; Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170022, Chile.
authors.forename: J P
authors.initials: JP
authors.lastname: Monrás
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile; Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380492, Chile.
authors.forename: L A
authors.initials: LA
authors.lastname: Saona
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile.
authors.forename: F A
authors.initials: FA
authors.lastname: Venegas
authors.affiliation: Department of Chemistry, Sam Houston State University, Huntsville, TX 77341, USA.
authors.forename: T G
authors.initials: TG
authors.lastname: Chasteen
authors.affiliation: Laboratorio de Microbiología Oral, Facultad de Odontología, Universidad de Chile, Santiago 8380492, Chile.
authors.forename: D
authors.initials: D
authors.lastname: Bravo
authors.affiliation: Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago 8370146, Chile. Electronic address: jose.perez@unab.cl.
authors.forename: J M
authors.initials: JM
authors.lastname: Pérez-Donoso
mesh_terms: D001692:Biological Transport; D032701:Biomimetics; D019187:Cadmium Compounds / Q000737:chemistry; D002478:Cells, Cultured; D003300:Copper / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004926:Escherichia coli / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry; D057230:Limit of Detection; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000191:economics / Q000379:methods*; D013691:Tellurium / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D003470:Culture Media; D014867:Water; D003300:Copper; D005978:Glutathione; D013691:Tellurium; C028337:cadmium telluride
keywords: Bacterial copper uptake kinetics; Biomimetic synthesis; CdTe–GSH; Copper quantification; Quantum dots; Stern–Volmer