title: Reactive oxygen species inhibited by titanium oxide coatings.
abstract: Titanium is a successful biomaterial that possesses good biocompatibility. It is covered by a surface layer of titanium dioxide, and this oxide may play a critical role in inhibiting reactive oxygen species, such as peroxynitrite, produced during the inflammatory response. In the present study, titanium dioxide was coated onto silicone substrates by radio-frequency sputtering. Silicone coating with titanium dioxide enhanced the breakdown of peroxynitrite by 79%. At physiologic pH, the peroxynitrite donor 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1) was used to nitrate 4-hydroxyphenylacetic acid (4-HPA) to form 4-hydroxy-3-nitrophenyl acetic acid (NHPA). Titanium dioxide-coated silicone inhibited the nitration of 4-HPA by 61% compared to aluminum oxide-coated silicone and 55% compared to uncoated silicone. J774A.1 mouse macrophages were plated on oxide-coated silicone and polystyrene and stimulated to produce superoxide and interleukin-6. Superoxide production was measured by the chemiluminescent reaction with 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (MCLA). Titanium dioxide-coated silicone exhibited a 55% decrease in superoxide compared to uncoated silicone and a 165% decrease in superoxide compared to uncoated polystyrene. Titanium dioxide-coated silicone inhibited IL-6 production by 77% compared to uncoated silicone. These results show that the anti-inflammatory properties of titanium dioxide can be transferred to the surfaces of silicone substrates.
authors.affiliation: Department of Bioengineering, University of California, San Diego, La Jolla, California 92037, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Suzuki
authors.forename: Julie
authors.initials: J
authors.lastname: Muyco
authors.forename: Joanna
authors.initials: J
authors.lastname: McKittrick
authors.forename: John A
authors.initials: JA
authors.lastname: Frangos
mesh_terms: D000535:Aluminum / Q000378:metabolism; D000818:Animals; D020099:Coated Materials, Biocompatible / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000378:metabolism; D010648:Phenylacetates / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012828:Silicones / Q000378:metabolism; D014025:Titanium / Q000378:metabolism*
chemical_list: D020099:Coated Materials, Biocompatible; D016207:Cytokines; D010648:Phenylacetates; D017382:Reactive Oxygen Species; D012828:Silicones; D030421:Peroxynitrous Acid; C009495:titanium dioxide; C008070:4-hydroxyphenylacetic acid; C002385:linsidomine; D000535:Aluminum; D014025:Titanium; D008981:Molsidomine