title: Photoactivation of quantum dot fluorescence following endocytosis.
abstract: We studied the fluorescence of quantum dots in cells. Coating quantum dots with cationic peptides caused them to be endocytosed and transported to lysosomes. After overnight incubation, their fluorescence apparently dimmed but became markedly "photoactivatable", increasing more than 3-fold within minutes on exposure to bright light, and decaying over hours in the dark. Photoactivation was greater in the presence of water than ethanol, and UV illumination compensated for lack of water during photoactivation. Dimming and photoactivation could affect the use of quantum dots as quantitative probes in vivo and lead to new uses, such as tracking molecular movement.
authors.affiliation: Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. jsilver@nih.gov
authors.forename: Jonathan
authors.initials: J
authors.lastname: Silver
authors.forename: Wu
authors.initials: W
authors.lastname: Ou
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D004307:Dose-Response Relationship, Radiation; D004705:Endocytosis / Q000502:physiology*; D011992:Endosomes / Q000502:physiology*; D005456:Fluorescent Dyes; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D008163:Luminescent Measurements / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*; D010777:Photochemistry / Q000379:methods*; D045663:Quantum Dots; D011829:Radiation Dosage
chemical_list: D005456:Fluorescent Dyes