title: Studies of photokilling of bacteria using titanium dioxide nanoparticles.
abstract: Metal pins used to apply skeletal traction or external fixation devices protruding through skin are susceptible to the increased incidence of pin site infection. In this work, we tried to establish the photokilling effects of titanium dioxide (TiO2) nanoparticles on an orthopedic implant with an in vitro study. In these photocatalytic experiments, aqueous TiO2 was added to the tested microorganism. The time effect of TiO2 photoactivation was evaluated, and the loss of viability of five different bacteria suspensions (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus hirae, and Bacteroides fragilis) was examined by the viable count procedure. The bactericidal effect of TiO2 nanoparticle-coated metal plates was also tested. The ultraviolet (UV) dosage used in this experiment did not affect the viability of bacteria, and all bacteria survived well in the absence of TiO2 nanoparticles. The survival curve of microorganisms in the presence of TiO2 nanoparticles showed that nearly complete killing was achieved after 50 min of UV illumination. The formation of bacterial colonies above the TiO2 nanoparticle-coated metal plates also decreased significantly. In this study, we clearly demonstrated the bactericidal effects of titanium dioxide nanoparticles. In the presence of UV light, the titanium dioxide nanoparticles can be applicable to medical facilities where the potential for infection should be controlled.
authors.affiliation: Department of Orthopedic Surgery, Taipei City Hospital, Taipei, Taiwan.
authors.forename: Yang-Hwei
authors.initials: YH
authors.lastname: Tsuang
authors.forename: Jui-Sheng
authors.initials: JS
authors.lastname: Sun
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Huang
authors.forename: Chung-Hsin
authors.initials: CH
authors.lastname: Lu
authors.forename: Walter Hong-Shong
authors.initials: WH
authors.lastname: Chang
authors.forename: Chien-Che
authors.initials: CC
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001441:Bacteroides fragilis / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects; D001858:Bone Nails / Q000382:microbiology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D015169:Colony Count, Microbial; D016983:Enterococcus / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D016267:External Fixators; D006801:Humans; D053768:Metal Nanoparticles; D017319:Photosensitizing Agents; D016459:Prosthesis-Related Infections / Q000517:prevention & control; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D017319:Photosensitizing Agents; C009495:titanium dioxide; D014025:Titanium