title: Photodynamic antibacterial effect of graphene quantum dots.
abstract: Synthesis of new antibacterial agents is becoming increasingly important in light of the emerging antibiotic resistance. In the present study we report that electrochemically produced graphene quantum dots (GQD), a new class of carbon nanoparticles, generate reactive oxygen species when photoexcited (470 nm, 1 W), and kill two strains of pathogenic bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. Bacterial killing was demonstrated by the reduction in number of bacterial colonies in a standard plate count method, the increase in propidium iodide uptake confirming the cell membrane damage, as well as by morphological defects visualized by atomic force microscopy. The induction of oxidative stress in bacteria exposed to photoexcited GQD was confirmed by staining with a redox-sensitive fluorochrome dihydrorhodamine 123. Neither GQD nor light exposure alone were able to cause oxidative stress and reduce the viability of bacteria. Importantly, mouse spleen cells were markedly less sensitive in the same experimental conditions, thus indicating a fairly selective antibacterial photodynamic action of GQD.
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Biljana Z
authors.initials: BZ
authors.lastname: Ristic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Marina M
authors.initials: MM
authors.lastname: Milenkovic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Ivana R
authors.initials: IR
authors.lastname: Dakic
authors.affiliation: Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia.
authors.forename: Biljana M
authors.initials: BM
authors.lastname: Todorovic-Markovic
authors.affiliation: Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia.
authors.forename: Momir S
authors.initials: MS
authors.lastname: Milosavljevic
authors.affiliation: Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia.
authors.forename: Milica D
authors.initials: MD
authors.lastname: Budimir
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Verica G
authors.initials: VG
authors.lastname: Paunovic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Miroslav D
authors.initials: MD
authors.lastname: Dramicanin
authors.affiliation: Vinca Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia. Electronic address: zormark@vinca.rs.
authors.forename: Zoran M
authors.initials: ZM
authors.lastname: Markovic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. Electronic address: vtrajkovic@med.bg.ac.rs.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Trajkovic
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000188:drug therapy; D006108:Graphite / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008027:Light; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D018384:Oxidative Stress / Q000187:drug effects; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D045663:Quantum Dots / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013203:Staphylococcal Infections / Q000188:drug therapy
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D006108:Graphite
keywords: Antibacterial; Graphene; Oxidative stress; Photodynamic; Quantum dot