title: Differences in subcellular distribution and toxicity of green and red emitting CdTe quantum dots.
abstract: Quantum dots (QDs) are emerging as alternative or complementary tools to the organic fluorescent dyes currently used in bioimaging. QDs hold several advantages over conventional fluorescent dyes including greater photostability and a wider range of excitation/emission wavelengths. However, recent work suggests that QDs exert deleterious effects on cellular processes. This study examined the subcellular localization and toxicity of cadmium telluride (CdTe) QDs and pharmacological means of preventing QD-induced cell death. The localization of CdTe QDs was found to depend upon QD size. CdTe QDs exhibited marked cytotoxicity in PC12 and N9 cells at concentrations as low as 10 microg/ml in chronic treatment paradigms. QD-induced cell death was characterized by chromatin condensation and membrane blebbing and was more pronounced with small (2r=2.2+/-0.1 nm), green emitting positively charged QDs than large (2r=5.2+/-0.1 nm), equally charged red emitting QDs. Pretreatment of cells with the antioxidant N-acetylcysteine and with bovine serum albumin, but not Trolox, significantly reduced the QD-induced cell death. These findings suggest that the size of QDs contributes to their subcellular distribution and that drugs can alter QD-induced cytotoxicity.
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Sciences Building, 3655 Promenade Sir-William-Osler, Montreal, Quebec H3G 1Y6, Canada.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Lovrić
authors.forename: Hassan S
authors.initials: HS
authors.lastname: Bazzi
authors.forename: Yan
authors.initials: Y
authors.lastname: Cuie
authors.forename: Genevieve R A
authors.initials: GR
authors.lastname: Fortin
authors.forename: Françoise M
authors.initials: FM
authors.lastname: Winnik
authors.forename: Dusica
authors.initials: D
authors.lastname: Maysinger
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D019187:Cadmium Compounds / Q000633:toxicity*; D002417:Cattle; D016923:Cell Death; D002460:Cell Line; D045744:Cell Line, Tumor; D005456:Fluorescent Dyes / Q000633:toxicity*; D051379:Mice; D017628:Microglia / Q000166:cytology; D018613:Microscopy, Confocal; D049329:Nanostructures; D016716:PC12 Cells; D045663:Quantum Dots; D051381:Rats; D012666:Semiconductors; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D012710:Serum Albumin, Bovine; D013691:Tellurium; C028337:cadmium telluride; D000111:Acetylcysteine