title: Carbon-dot-based ratiometric fluorescent probe for imaging and biosensing of superoxide anion in live cells.
abstract: In this article, a ratiometric fluorescent biosensor for O2(•-) was developed, by employing carbon dots (C-Dots) as the reference fluorophore and hydroethidine (HE), a specific organic molecule toward O2(•-), playing the role as both specific recognition element and response signal. The hybrid fluorescent probe CD-HE only emitted at 525 nm is ascribed to C-Dots, while HE was almost nonfluorescent, upon excitation at 488 nm. However, after reaction with O2(•-), a new emission peak ascribed to the reaction products of HE and O2(•-) was clearly observed at 610 nm. Meanwhile, this peak gradually increased with the increasing concentration of O2(•-) but the emission peak at 525 nm stayed constant, leading to a ratiometric detection of O2(•-). The inorganic-organic fluorescent sensor exhibited high sensitivity, a broad dynamic linear range of ~5 × 10(-7)-1.4 × 10(-4) M, and low detection limit down to 100 nM. The present probe also showed high accuracy and excellent selectivity for O2(•-) over other reactive oxygen species (ROS), metal ions, and so on. Moreover, the C-Dot-based inorganic-organic probe demonstrated long-term stability against pH changes and continuous light illumination, good cell-permeability, and low cytotoxicity. Accordingly, the developed fluorescent biosensor was eventually applied for intracellular bioimaging and biosensing of O2(•-) changes upon oxidative stress.
authors.affiliation: Department of Chemistry, Tongji University , Siping Road 1239, Shanghai 200092, P. R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Changqin
authors.initials: C
authors.lastname: Ding
authors.forename: Anwei
authors.initials: A
authors.lastname: Zhu
authors.forename: Yang
authors.initials: Y
authors.lastname: Tian
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000633:toxicity; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D057054:Molecular Imaging / Q000379:methods*; D018384:Oxidative Stress; D010617:Phenanthridines / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000032:analysis; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013481:Superoxides / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D010617:Phenanthridines; D017382:Reactive Oxygen Species; D013481:Superoxides; C058428:hydroethidine; D002244:Carbon