title: Preparation of excitation-independent photoluminescent graphene quantum dots with visible-light excitation/emission for cell imaging.
abstract: We report the first pyrrole-ring surface-functionalized graphene quantum dots (p-GQDs) prepared by a two-step hydrothermal approach under microwave irradiation in an ammonia medium. The most distinct feature of the functionalized GQDs is that both the excitation and emission wavelengths fall into the visible-light region. The p-GQDs are excited by visible light at λ(ex) 490 nm (2.53 eV) to emit excitation-independent photoluminescence at a maximum wavelength of λ(em) 550 nm. This is thus far the longest emission wavelength reported for GQDs. Stable photoluminescence is achieved at pH 4-10 with an ionic strength of 1.2 mol L(-1) KCl. These features make the p-GQDs excellent probes for bio-imaging and bio-labeling, which is demonstrated by imaging live HeLa cells.
authors.affiliation: Research Center for Analytical Sciences, Box 332, Northeastern University, Shenyang 110819 (P.R. China), Fax: (+86) 24-83676698.
authors.forename: Shuai
authors.initials: S
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Hai
authors.forename: Chang
authors.initials: C
authors.lastname: Xia
authors.forename: Xu-Wei
authors.initials: XW
authors.lastname: Chen
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Wang
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D006108:Graphite / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008027:Light; D018613:Microscopy, Confocal; D011758:Pyrroles / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry* / Q000633:toxicity
chemical_list: D011758:Pyrroles; D006108:Graphite
keywords: UV/Vis spectroscopy; cell imaging; graphene; pyrroles; quantum dots