title: Eco-friendly intracellular biosynthesis of CdS quantum dots without changing Escherichia coli's antibiotic resistance.
abstract: In the paper, a green and efficient biosynthetical technique was reported for preparing cadmium sulfide (CdS) quantum dots, in which Escherichia coli (E. coli) was chosen as a biomatrix. Fluorescence emission spectra and fluorescent microscopic photographs revealed that as-produced CdS quantum dots had an optimum fluorescence emission peak located at 470nm and emitted a blue-green fluorescence under ultraviolet excitation. After extracted from bacterial cells and located the nanocrystals' foci in vivo, the CdS quantum dots showed a uniform size distribution by transmission electron microscope. Through the systematical investigation of the biosynthetic conditions, including culture medium replacement, input time point of cadmium source, working concentrations of raw inorganic ions, and co-cultured time spans of bacteria and metal ions in the bio-manufacture, the results revealed that CdS quantum dots with the strongest fluorescence emission were successfully prepared when E. coli cells were in stationary phase, with the replacement of culture medium and following the incubation with 1.0×10-3mol/L cadmium source for 2 days. Results of antimicrobial susceptibility testing indicated that the sensitivities to eight types of antibiotics of E. coli were barely changed before and after CdS quantum dots were prepared in the mild temperature environment, though a slight fall of antibiotic resistance could be observed, suggesting hinted the proposed technique of producing quantum dots is a promising environmentally low-risk protocol.
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China.
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Yan
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China.
authors.forename: Qing-Qing
authors.initials: QQ
authors.lastname: Du
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China.
authors.forename: Dong-Yu
authors.initials: DY
authors.lastname: Wan
authors.affiliation: Department of Analytical Chemistry, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjia Lane, Gulou District, Nanjing 210009, China. Electronic address: wushengmei80@163.com.
authors.forename: Sheng-Mei
authors.initials: SM
authors.lastname: Wu
mesh_terms: D019187:Cadmium Compounds / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D055772:Green Chemistry Technology; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence; D013440:Sulfides / Q000378:metabolism*
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide
keywords: Antibiotic resistance; Biosynthesis; Escherichia coli; Quantum dots