title: Bright-Yellow-Emissive N-Doped Carbon Dots: Preparation, Cellular Imaging, and Bifunctional Sensing.
abstract: Fluorescent carbon dots (CDs) have attracted much attention in recent years because of their superior optical and chemical properties, thus demonstrating many potential applications. However, the previously reported CDs mostly show strong emission only in the blue-light region, and the long-wavelength (i.e., yellow- to red-light) emissions are usually very weak. Such a drawback restricts their further applications, particularly in the biology-relevant fields. Herein, a rare example of N-doped CDs that emit bright-yellow fluorescence (i.e., y-CDs) is reported using 1,2,4-triaminobenzene as carbon precursor. The as-prepared y-CDs exhibit not only respectable emission quantum yield and highly optical stabilities but superior biocompatibility and biolabeling potentials. In addition, the y-CDs are found to show an interesting "ON-OFF-ON" three-state emission with the stepwise addition of Ag(+) and cysteine (Cys), indicating potential applications as a bifunctional sensing platform. Thanks to the highly intense emission of y-CDs, the gradual quenching and restoration of their fluorescence with the addition of Ag(+) and further Cys could also be observed with the naked eye. More importantly, the ensemble of the y-CDs and Ag(+) demonstrates practicability for the highly selective and sensitive detection of Cys in human plasma samples with satisfactory results.
authors.affiliation: Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences , Ningbo 315201, PR China.|Department of Applied Physics, Chongqing University , Chongqing 401331, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Jiang
authors.affiliation: Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences , Ningbo 315201, PR China.
authors.forename: Shan
authors.initials: S
authors.lastname: Sun
authors.affiliation: Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences , Ningbo 315201, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences , Ningbo 315201, PR China.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Applied Physics, Chongqing University , Chongqing 401331, PR China.
authors.forename: Congzhong
authors.initials: C
authors.lastname: Cai
authors.affiliation: Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences , Ningbo 315201, PR China.
authors.forename: Hengwei
authors.initials: H
authors.lastname: Lin
mesh_terms: D002244:Carbon / Q000737:chemistry*; D016923:Cell Death / Q000187:drug effects; D003545:Cysteine / Q000032:analysis; D005453:Fluorescence; D006801:Humans; D049449:Luminescence; D061986:MCF-7 Cells; D018625:Microscopy, Atomic Force; D057054:Molecular Imaging / Q000379:methods*; D012834:Silver / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet; D047408:gamma-Cyclodextrins / Q000737:chemistry / Q000494:pharmacology
chemical_list: D047408:gamma-Cyclodextrins; D012834:Silver; D002244:Carbon; D003545:Cysteine
keywords: N-doping; bifunctional sensing; bioimaging; carbon dots; yellow emission