title: A Classic Near-Infrared Probe Indocyanine Green for Detecting Singlet Oxygen.
abstract: The revelation of mechanisms of photodynamic therapy (PDT) at the cellular level as well as singlet oxygen (¹O₂) as a second messengers requires the quantification of intracellular ¹O₂. To detect singlet oxygen, directly measuring the phosphorescence emitted from ¹O₂ at 1270 nm is simple but limited for the low quantum yield and intrinsic efficiency of ¹O₂ emission. Another method is chemically trapping ¹O₂ and measuring fluorescence, absorption and Electron Spin Resonance (ESR). In this paper, we used indocyanine green (ICG), the only near-infrared (NIR) probe approved by the Food and Drug Administration (FDA), to detect ¹O₂ in vitro. Once it reacts with ¹O₂, ICG is decomposed and its UV absorption at 780 nm decreases with the laser irradiation. Our data demonstrated that ICG could be more sensitive and accurate than Singlet Oxygen Sensor Green reagent(®) (SOSG, a commercialized fluorescence probe) in vitro, moreover, ICG functioned with Eosin Y while SOSG failed. Thus, ICG would reasonably provide the possibility to sense ¹O₂ in vitro, with high sensitivity, selectivity and suitability to most photosensitizers.
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. tangchengyi_nju@163.com.|Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China. tangchengyi_nju@163.com.
authors: Cheng-Yi
authors: CY
authors: Tang
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. cdwfyao@126.com.
authors: Feng-Yao
authors: FY
authors: Wu
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. 13404159963@163.com.
authors: Min-Kai
authors: MK
authors: Yang
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. 15856342898@163.com.
authors: Yu-Min
authors: YM
authors: Guo
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. guihua.lu@nju.edu.cn.|Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China. guihua.lu@nju.edu.cn.
authors: Gui-Hua
authors: GH
authors: Lu
authors: State Key Laboratory of Pharmaceutical Biotechnology, NJU-NJFU Joint Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China. yangyh@nju.edu.cn.|Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China. yangyh@nju.edu.cn.
authors: Yong-Hua
authors: YH
authors: Yang
mesh_terms: D005456:Fluorescent Dyes; D007208:Indocyanine Green; D007259:Infrared Rays; D010778:Photochemotherapy; D017319:Photosensitizing Agents; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D026082:Singlet Oxygen / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D007208:Indocyanine Green
keywords: indocyanine green (ICG); singlet oxygen (1O2)