title: An intramolecular charge transfer process based fluorescent probe for monitoring subtle pH fluctuation in living cells.
abstract: It is crucial to monitor intracellular pH values and their fluctuation since the organelles of cells have different pH distribution. Herein we construct a new small molecule fluorescent probe HBT-O for monitoring the subtle pH values within the scope of neutral to acid in living cells. The probe exhibited good water solubility, a marked turquoise to olivine emission color change in response to pH, and tremendous fluorescence hypochromatic shift of ∼50nm (1718cm-1) as well as the increased fluorescence intensity when the pH value changed from neutral to acid. Thus, the probe HBT-O can distinguish the subtle changes in the range of normal pH values from neutral to acid with significant fluorescence changes. These properties can be attributed to the intramolecular charge transfer (ICT) process of the probe upon protonation in buffer solutions at varied pH values. Moreover, the probe was reversible and nearly non-toxic for living cells. Then the probe was successfully used to detect pH fluctuation in living cells by exhibiting different fluorescence colors and intensity. These findings demonstrate that the probe will find useful applications in biology and biomedical research.
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206, People's Republic of China; Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China.
authors.forename: Mingtai
authors.initials: M
authors.lastname: Sun
authors.affiliation: State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Libo
authors.initials: L
authors.lastname: Du
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China.
authors.forename: Huan
authors.initials: H
authors.lastname: Yu
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China.
authors.forename: Kui
authors.initials: K
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206, People's Republic of China; Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China. Electronic address: shwang@iim.ac.cn.
authors.forename: Suhua
authors.initials: S
authors.lastname: Wang
mesh_terms: D000143:Acids / Q000737:chemistry*; D003116:Color; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements / Q000379:methods; D061986:MCF-7 Cells; D018613:Microscopy, Confocal / Q000379:methods; D008956:Models, Chemical; D015394:Molecular Structure; D013053:Spectrophotometry / Q000379:methods
chemical_list: D000143:Acids; D005456:Fluorescent Dyes
keywords: Benzothiazole derivative; Fluorescent probe; Intramolecular charge transfer; Living cell imaging; Ratiometric; pH sensor