title: Use of fluorescent probes for ROS to tease apart Type I and Type II photochemical pathways in photodynamic therapy.
abstract: Photodynamic therapy involves the excitation of a non-toxic dye by harmless visible light to produce a long-lived triplet state that can interact with molecular oxygen to produce reactive oxygen species (ROS), which can damage biomolecules and kill cells. ROS produced by electron transfer (Type 1) include superoxide, hydrogen peroxide and hydroxyl radical (HO), while singlet oxygen (1O2) is produced by energy transfer. Diverse methods exist to distinguish between these two pathways, some of which are more specific or more sensitive than others. In this review we cover the use of two fluorescence probes: singlet oxygen sensor green (SOSG) detects1O2; and 4-hydroxyphenyl-fluorescein (HPF) that detects HO. Interesting data was collected concerning the photochemical pathways of functionalized fullerenes compared to tetrapyrroles, stable synthetic bacteriochlorins with and without central metals, phenothiazinium dyes interacting with inorganic salts such as azide.
authors.affiliation: Department of Pharmacy, University of Copenhagen, Universitetsparken, 2, DK-2100, Copenhagen, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Garcia-Diaz
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Huang
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA. Electronic address: Hamblin@helix.mgh.harvard.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004579:Electron Transport; D004735:Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D008027:Light; D010778:Photochemotherapy; D011166:Porphyrins / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry* / Q000378:metabolism; D026082:Singlet Oxygen / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D045725:Tetrapyrroles / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D011166:Porphyrins; D017382:Reactive Oxygen Species; D045725:Tetrapyrroles; C452433:bacteriochlorin; D013481:Superoxides; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide
keywords: Bacteriochlorins; Fullerenes; Hydroxyl radical; Hydroxyphenyl fluorescein; Phenothiazinium salts; Photodynamic therapy; Singlet oxygen; Singlet oxygen sensor green