title: Micro-organism-triggered release of silver nanoparticles from biodegradable oxide carriers allows preparation of self-sterilizing polymer surfaces.
abstract: The antimicrobial activity of silver has attracted significant research interest and contributes to an exponentially growing use of this noble metal in commodity products. In this investigation, we describe a general approach to increase the antimicrobial activity of a silver-containing surface by two to three orders of magnitude. The use of 1-2-nm silver particles decorating the surface of 20-50-nm carrier particles consisting of a phosphate-based, biodegradable ceramic allows the triggered release of silver in the presence of a growing microorganism. This effect is based on the organism's requirements for mineral uptake during growth creating a flux of calcium, phosphate, and other ions to the organism. The growing micro-organism dissolves the carrier containing these nutrients and thereby releases the silver nanoparticles. Further, we demonstrate the rapid self-sterilization of polymer surfaces containing silver on calcium phosphate nanoparticles using a series of human pathogens. Colony-forming units (viable bacteria or fungi counts) have been routinely reduced below detection limit and suggest application of these self-sterilizing surfaces in hospital environments, food and pharmaceutical processing, and personal care.
authors.affiliation: ETH Zurich, Institute for Chemical and Bioengineering, HCI E107, 8093 Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Loher
authors.forename: Oliver D
authors.initials: OD
authors.lastname: Schneider
authors.forename: Tobias
authors.initials: T
authors.lastname: Maienfisch
authors.forename: Stefan
authors.initials: S
authors.lastname: Bokorny
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
mesh_terms: D001234:Aspergillus niger / Q000187:drug effects / Q000502:physiology; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology; D053768:Metal Nanoparticles; D017348:Microscopy, Electron, Scanning Transmission; D046529:Microscopy, Electron, Transmission; D010087:Oxides / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000502:physiology; D012834:Silver / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology; D013499:Surface Properties
chemical_list: D010087:Oxides; D011108:Polymers; D012834:Silver