title: Photocatalytic TiO2 particles confer superior antibacterial effects in a nutrition-rich environment: an in vitro study.
abstract: Titanium dioxide (TiO(2)) is known to confer photocatalytic bactericidal effects under ultraviolet (UV) irradiation. Few reports are available, however, on the clinical applications of TiO(2) particle mixtures. Our objective in the present research was to evaluate the in vitro bactericidal effects of a TiO(2) particle mixture in a nutrition-rich biological environment. A bacterial suspension of Staphylococcus aureus and epidermidis 3 x 10(3) CFU/mL was added to a TiO(2) particle mixture (0.038 mg/mL) containing mainly sodium percarbonate and citric acid. To simulate a biological environment, 40 microL of 10% bovine serum albumin was added and the culture temperature was maintained at 37 degrees C. The resulting product was irradiated by UV light and the bacterial survival rate was calculated for each time of UV irradiation. In the control sample treated with distilled water + UV, the bacteria survived at a high rate even after 180 min. In the TiO(2) mixture + UV sample, meanwhile, the bacterial survival rate dropped to 43.8% and 6.0% of the baseline values in S. aureus and S. epidermidis, respectively, after 60 min of UV irradiation. The photocatalytic antibacterial action of the TiO(2) particle mixture was high even in a protein-rich biological environment.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hiura
authors.forename: Hironobu
authors.initials: H
authors.lastname: Koseki
authors.forename: Koutaro
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Asahara
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tsurumoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shindo
authors.forename: Koumei
authors.initials: K
authors.lastname: Baba
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taoda
authors.forename: Nao
authors.initials: N
authors.lastname: Terasaki
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000528:radiation effects; D002417:Cattle; D013211:Staphylococcus aureus / Q000187:drug effects / Q000528:radiation effects; D014025:Titanium; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D014025:Titanium