title: Synthesis of water-dispersible zinc oxide quantum dots with antibacterial activity and low cytotoxicity for cell labeling.
abstract: Typical photoluminescent semiconductor nanoparticles, called quantum dots (QDs), have potential applications in biological labeling. When used to label stem cells, QDs may impair the differentiation capacity of the stem cells. In this study, we synthesized zinc oxide (ZnO) QDs in methanol with an average size of ∼2 nm. We then employed two different types of polyethylene glycol (PEG) molecules (SH-PEG-NH2 and NH2-PEG-NH2) to conjugate ZnO QDs and made them water-dispersible. Fourier transform infrared spectroscopy spectra indicated the attachment of PEG molecules on ZnO QDs. No obvious size alteration was observed for ZnO QDs after PEG conjugation. The water-dispersible ZnO QDs still retained the antibacterial activity and fluorescence intensity. The cytotoxicity evaluation revealed that ZnO QDs at higher concentrations decreased cell viability but were generally safe at 30 ppm or below. Cell lines of hepatocytes (HepG2), osteoblasts (MC3T3-E1) and mesenchymal stem cells (MSCs) were successfully labeled by the water-dispersible ZnO QDs at 30 ppm. The ZnO QD-labeled MSCs maintained their stemness and differentiation capacity. Therefore, we conclude that the water-dispersible ZnO QDs developed in this study have antibacterial activity, low cytotoxicity, and proper labeling efficiency, and can be used to label a variety of cells including stem cells.
authors.affiliation: Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan, Republic of China. Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
authors.forename: Shan-hui
authors.initials: SH
authors.lastname: Hsu
authors.forename: Ying Yi
authors.initials: YY
authors.lastname: Lin
authors.forename: Sherry
authors.initials: S
authors.lastname: Huang
authors.forename: Kwok Wai
authors.initials: KW
authors.lastname: Lem
authors.forename: Dinh Huong
authors.initials: DH
authors.lastname: Nguyen
authors.forename: Dai Soo
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D053687:Adult Stem Cells / Q000166:cytology / Q000187:drug effects; D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D004853:Epoxy Resins / Q000138:chemical synthesis / Q000737:chemistry; D004926:Escherichia coli / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D057446:Hydrodynamics; D051379:Mice; D008826:Microbial Sensitivity Tests; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010796:Phthalic Anhydrides / Q000138:chemical synthesis / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D013194:Staining and Labeling; D055672:Static Electricity; D014867:Water / Q000737:chemistry*; D015034:Zinc Oxide / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004853:Epoxy Resins; D010796:Phthalic Anhydrides; D017382:Reactive Oxygen Species; D014867:Water; C005752:araldite; D015034:Zinc Oxide