title: Dual action antimicrobial surfaces via combined nitric oxide and silver release.
abstract: Recent research has demonstrated that silver sulfadiazine and small molecule nitric oxide (NO) donors kill a number of bacterial species synergistically in solution-based assays. Herein, we report on multilayered silica-based xerogels that release both NO and silver. Release of each agent was achieved by exposing amine-modified xerogels to high pressures of NO, and doping silver nitrate (AgNO3) into an alkyl-silane xerogel. Total achievable releases were 3.5 μmol cm(-2) and 1.7 ppm for NO and Ag+, respectively, with release of each agent controlled independent of the other. The NO/Ag+-releasing coating reduced bacterial adhesion and exhibited greater-than-additive killing against both Pseudomonas aeruginosa and Staphylococcus aureus. In contrast, cytotoxicity assays against L929 fibroblasts suggest that the combination does not cause greater-than-additive killing to mammalian cells. Such materials may prove useful in the design of biomedical devices prone to infection such as bone and surgical screws.
authors.affiliation: University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina, 27599.
authors.forename: Wesley L
authors.initials: WL
authors.lastname: Storm
authors.forename: Justin A
authors.initials: JA
authors.lastname: Johnson
authors.forename: Brittany V
authors.initials: BV
authors.lastname: Worley
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Slomberg
authors.forename: Mark H
authors.initials: MH
authors.lastname: Schoenfisch
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D015169:Colony Count, Microbial; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D051379:Mice; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008856:Microscopy, Fluorescence; D009569:Nitric Oxide / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012834:Silver / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013499:Surface Properties
chemical_list: D000890:Anti-Infective Agents; D005782:Gels; D009569:Nitric Oxide; D012834:Silver
keywords: active release; antimicrobial; combination therapy; nitric oxide; silver nitrate; sol-gel