Micro-organism-triggered release of silver nanoparticles from biodegradable oxide carriers allows preparation of self-sterilizing polymer surfaces.
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.
Loher
Stefan
S
ETH Zurich, Institute for Chemical and Bioengineering, HCI E107, 8093 Zurich, Switzerland.
Schneider
Oliver D
OD
Maienfisch
Tobias
T
Bokorny
Stefan
S
Stark
Wendelin J
WJ
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
D010087:Oxides; D011108:Polymers; D012834:Silver