title: Biocompatibility and antibacterial activity of nitrogen-doped titanium dioxide nanoparticles for use in dental resin formulations.
abstract: The addition of antibacterial functionality to dental resins presents an opportunity to extend their useful lifetime by reducing secondary caries caused by bacterial recolonization. In this study, the potential efficacy of nitrogen-doped titanium dioxide nanoparticles for this purpose was determined. Nitrogen doping was carried out to extend the ultraviolet absorbance into longer wavelength blue light for increased biocompatibility. Titanium dioxide nanoparticles (approximately 20-30 nm) were synthesized with and without nitrogen doping using a sol-gel method. Ultraviolet-Visible spectroscopy indicated a band of trap states, with increasing blue light absorbance as the concentration of the nitrogen dopant increased. Electron paramagnetic resonance measurements indicated the formation of superoxide and hydroxyl radicals upon particle exposure to visible light and oxygen. The particles were significantly toxic toEscherichia coliin a dose-dependent manner after a 1-hour exposure to a blue light source (480 nm). Intracellular reactive oxygen species assay demonstrated that the particles caused a stress response in human gingival epithelial cells when exposed to 1 hour of blue light, though this did not result in detectable release of cytokines. No decrease in cell viability was observed by water-soluble tetrazolium dye assay. The results show that nitrogen-doped titanium dioxide nanoparticles have antibacterial activity when exposed to blue light, and are biocompatible at these concentrations.
authors.affiliation: Biomaterials and Environmental Surveillance Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio, Fort Sam Houston, San Antonio, TX.
authors.forename: Andrew
authors.initials: A
authors.lastname: Zane
authors.affiliation: Department of Chemistry and Biochemistry.
authors.forename: Ranfang
authors.initials: R
authors.lastname: Zuo
authors.affiliation: Department of Biological Chemistry and Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, USA.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Villamena
authors.affiliation: Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Institute of Materials and Environmental Chemistry; Department of Physics, MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Budapest, Hungary.
authors.forename: Antal
authors.initials: A
authors.lastname: Rockenbauer
authors.affiliation: Biomaterials and Environmental Surveillance Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio, Fort Sam Houston, San Antonio, TX.
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Digeorge Foushee
authors.affiliation: Biomaterials and Environmental Surveillance Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio, Fort Sam Houston, San Antonio, TX.
authors.forename: Kristin
authors.initials: K
authors.lastname: Flores
authors.affiliation: Department of Chemistry and Biochemistry.
authors.forename: Prabir K
authors.initials: PK
authors.lastname: Dutta
authors.affiliation: Biomaterials and Environmental Surveillance Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio, Fort Sam Houston, San Antonio, TX.
authors.forename: Amber
authors.initials: A
authors.lastname: Nagy
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002384:Catalysis; D002470:Cell Survival; D004578:Electron Spin Resonance Spectroscopy; D004847:Epithelial Cells / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D005881:Gingiva / Q000187:drug effects; D006801:Humans; D017665:Hydroxyl Radical / Q000737:chemistry; D008027:Light; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D009585:Nitrogen Dioxide / Q000737:chemistry; D018384:Oxidative Stress; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D017382:Reactive Oxygen Species; D012117:Resins, Synthetic; C009495:titanium dioxide; D017665:Hydroxyl Radical; D014025:Titanium; D009584:Nitrogen; D009585:Nitrogen Dioxide
keywords: antibacterial activity; nitrogen doping; titanium dioxide