title: Peptide-Decorated Tunable-Fluorescence Graphene Quantum Dots.
abstract: We report here the synthesis of graphene quantum dots with tunable size, surface chemistry, and fluorescence properties. In the size regime 15-35 nm, these quantum dots maintain strong visible light fluorescence (mean quantum yield of 0.64) and a high two-photon absorption (TPA) cross section (6500 Göppert-Mayer units). Furthermore, through noncovalent tailoring of the chemistry of these quantum dots, we obtain water-stable quantum dots. For example, quantum dots with lysine groups bind strongly to DNA in solution and inhibit polymerase-based DNA strand synthesis. Finally, by virtue of their mesoscopic size, the quantum dots exhibit good cell permeability into living epithelial cells, but they do not enter the cell nucleus.
authors.affiliation: Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Bedanga
authors.initials: B
authors.lastname: Sapkota
authors.affiliation: Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Benabbas
authors.affiliation: Center for Nanoscale Systems, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Hao-Yu Greg
authors.initials: HG
authors.lastname: Lin
authors.affiliation: Department of Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Wentao
authors.initials: W
authors.lastname: Liang
authors.affiliation: Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0001-6958-2836
authors.initials: P
authors.lastname: Champion
authors.affiliation: Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States.|Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Meni
authors.identifier: http://orcid.org/0000-0002-9837-0004
authors.initials: M
authors.lastname: Wanunu
mesh_terms: D005453:Fluorescence; D006108:Graphite; D010455:Peptides; D017785:Photons; D045663:Quantum Dots
chemical_list: D010455:Peptides; D006108:Graphite
keywords: DNA binding; biological imaging; graphene quantum dots; peptides; tunable fluorescence; two-photon fluorescence