title: Silver ions eluted from partially protected silver nanoparticles.
abstract: The most prominent character of a new type of antibacterial urological catheters is the zebra-stripe pattern of a silver film, which is plated electroless on their interior wall and capped by a very thin semipermeable layer of parylene. This design effectively controls the release rate of Ag(+) ions in artificial urine, which has been measured as function of time with optical emission spectroscopy. By evaluating the minimum inhibitory concentration against certain strains of bacteria with solutions of AgNO3 of known concentration with the method of optical density and applying this analysis to the silver-eluting catheters, it was shown that this moderation prolongs the period of their application significantly. But to act as antibacterial agent in chlorine-containing solutions, as in urine, the presence of urea is required to avoid precipitation of AgCl and to meet or even exceed the minimum inhibitory concentration of Ag(+). The quality of the silver depot layer was further determined by the deposition rate and its morphology, which revealed that the film consisted of grains with a mean size of 150 nm.
authors.affiliation: Laboratory for Surface Refinement and Thin Film Technology, Munich University of Applied Sciences, Munich D-80335, Bavaria, Germany.
authors.forename: Hamideh
authors.initials: H
authors.lastname: Heidari Zare
authors.affiliation: Laboratory for Surface Refinement and Thin Film Technology, Munich University of Applied Sciences, Munich D-80335, Bavaria, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Düttmann
authors.affiliation: Laboratory for Surface Refinement and Thin Film Technology, Munich University of Applied Sciences, Munich D-80335, Bavaria, Germany.
authors.forename: Attila
authors.initials: A
authors.lastname: Vass
authors.affiliation: Laboratory for Surface Refinement and Thin Film Technology, Munich University of Applied Sciences, Munich D-80335, Bavaria, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Franz
authors.affiliation: University Hospital of the State of Schleswig-Holstein at Lübeck, Ratzeburger Allee 160, Lübeck D-23538, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Jocham
mesh_terms: D000890:Anti-Infective Agents / Q000493:pharmacokinetics*; D001419:Bacteria / Q000187:drug effects; D007477:Ions / Q000493:pharmacokinetics*; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000493:pharmacokinetics*; D013057:Spectrum Analysis; D062885:Urinary Catheters
chemical_list: D000890:Anti-Infective Agents; D007477:Ions; D012834:Silver