title: Quantum dot-mediated photoproduction of reactive oxygen species for cancer cell annihilation.
abstract: While semiconductor quantum dots produce little singlet oxygen, they may undergo Type I photoreactions to produce other reactive oxygen species (ROS) to kill cells. CdTe quantum dots coated with thioglycolic acid were used to test that possibility. Some thiol ligands were purposely removed to regenerate the surface electron traps that were passivated by the ligand. This allowed photoinduced electrons to dwell on the surface long enough to be gathered by nearby oxygen molecules to produce ROS. The photocytotoxicity of these quantum dots was tested on nasopharyngeal carcinoma cells. Photokilling was shown to be drug and light dose dependent. Using 0.6 mum quantum dots for incubation and 4.8 J cm(-2) for irradiation, about 80% of the cells were annihilated. These quantum dots promised to be potent sensitizers for photoannihilation of cancer cells.
authors.affiliation: Surface Physics Laboratory (National Key Laboratory), Physics Department, Fudan University, Shanghai, China.
authors.forename: Ji-Yao
authors.initials: JY
authors.lastname: Chen
authors.forename: Yee-Man
authors.initials: YM
authors.lastname: Lee
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.forename: Nai-Ki
authors.initials: NK
authors.lastname: Mak
authors.forename: Ricky Ngok-Shun
authors.initials: RN
authors.lastname: Wong
authors.forename: Wing-Hong
authors.initials: WH
authors.lastname: Chan
authors.forename: Nai-Ho
authors.initials: NH
authors.lastname: Cheung
mesh_terms: D002104:Cadmium; D016923:Cell Death; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000628:therapy; D009369:Neoplasms / Q000628:therapy*; D010778:Photochemotherapy / Q000379:methods; D045663:Quantum Dots; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013691:Tellurium; D013864:Thioglycolates; D014407:Tumor Cells, Cultured
chemical_list: D017382:Reactive Oxygen Species; D013864:Thioglycolates; D002104:Cadmium; D013691:Tellurium