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Antibacterial coatings containing different amount of metallic silver nanoclusters embedded in a silica matrix have been deposited by co-sputtering technique on several different polymers used in mobile telephones components such as: screens, covers, and microphone felts. Sputtering parameters have been varied to obtain different coating thickness and silver content, in order to meet antibacterial, aesthetic and functional requirements for each component. In particular, an antibacterial functionality has been obtained for screens, covers and felts without affecting their respective transparency, aesthetic and acoustic properties. The optimal parameters for each part have been used to obtain an antibacterial mobile telephone suitable for personnel operating in hospitals or other environments with potentially high bacterial contamination. [ABSTRACT FROM AUTHOR]

Abstract: The microbiological contamination on board of spacecraft and orbital stations is a relevant problem in prolonged space exploration. For this purpose, an antibacterial silver nanocluster silica composite coating was deposited on a commercial polymer Combitherm®, suitable for aerospace application, using the radio frequency (RF) co-sputtering technique. The presence of metallic silver nanoclusters and silica was confirmed by energy dispersion spectrometry (EDS), x-ray photoelectron spectroscopy (XPS) and localized surface plasmon resonance (LSPR) detected through UV–visible absorption spectrophotometry (UV–Vis). The atomic force microscope (AFM) evidenced the coating morphology. The slight hydrophobicity of both coated and uncoated samples was revealed through the contact angle measurement. The antimicrobial behavior was verified through evaluation of the inhibition halo against several bacterial and fungal species. The coating enhanced the Combitherm® nano-hardness and its resistance to tensile and perforation tests; the coating wear resistance was measured by abrasion test against Kevlar. A folding procedure on the coated Combitherm® and storage in air for three months was also carried out without deterioration of the measured properties. The coating deposition did not influence the air permeability of Combitherm®. [Copyright &y& Elsevier]

Abstract: Silver nanocluster–silica composite coatings have been deposited by radio frequency (RF) co-sputtering on silica substrates. UV–visible absorption and X-ray diffraction spectra of the as deposited and heated samples revealed metal silver nanoclusters of different size, depending on the annealing treatment. The antibacterial activity of several as deposited and annealed samples has been verified in accordance to National Committee for Clinical Laboratory Standards (NCCLS). The antibacterial activity of these coatings was detected up to 450°C. [Copyright &y& Elsevier]

Excellent mechanical, thermal and chemical properties make Vectran™ fibres an attractive material to be used in high end applications. Its aerospace applications, as in inflatable light weight habitat module, require functional coating to provide antibacterial protection to ensure safe environment for the astronauts. In this study, woven Vectran™ fabric was coated with an antibacterial silver nanoclusters/silica composite coating by means of radio frequency co-sputtering technique. The successful deposition of the silver nanoclusters embedded in the silica matrix of the composite coating was confirmed by morphological, compositional and structural analysis. The coating sustained 10 washing cycles with partial dissolution of the coating during washing. Silver leaching test verified the gradual and progressive release of ionic silver in aqueous media in the range 0.03 ppm–0.43 ppm within 72 h of immersion in water. Antibacterial properties of the coated Vectran™ fabric were confirmed in inhibition halo test against Staphylococcus aureus and Escherichia coli on as deposited as well as aged samples. An inhibition halo of up to 2 mm was observed for as deposited samples while after UV exposure, the samples formed inhibition halo of 4 mm. The percutaneous absorption test demonstrated a very low release of silver into epidermis and dermis. The effect of the coating on mechanical properties of the as deposited Vectran fabric was assessed through mechanical characterizations including tensile, tear and abrasion test. • Uniform coverage and distribution of silver nanoclusters on the fibre surface • Gradual release of silver ions from the composite coating • Satisfactory washing resistance of the composite coating • Mechanical properties of the fabric preserved [ABSTRACT FROM AUTHOR]

With the goal of preventing abdominal infections after implanting prostheses for hernia repair, polypropylene prostheses were coated with a silver nanoclusters-silica composite (Ag/SiO 2 ) layer, by means of a sputtering process, to confer antibacterial properties. The Ag/SiO 2 coating was deposited, with good uniformity and adhesion, either onto hernia prostheses (CMC) made of two polypropylene layers (macroporous light mesh and thin transparent film), or onto the mesh layer alone. The coating was optimized to achieve a good balance between antibacterial activity and biocompatibility. Antibacterial activity, fibroblast growth on CMC/mesh layer alone, in the presence/absence of Ag/SiO 2 , collagen, and some cytokines involved in inflammation and healing processes, were determined. Preliminary experiments showed that when both layers of CMC were entirely coated, antibacterial properties were achieved while losing prosthesis biocompatibility. Coating the entire CMC was a complex process, thus for subsequent experiments the mesh layer alone was coated, being the antibacterial properties unaffected by this choice and the mesh the part of CMC exposed to possible infection. With a duty cycle of 1 s over 24 on an Ag target, for 15 min deposition time, antibacterial activity, evaluated through the quantitative Colony–Forming Units test, was positive; fibroblasts colonized the coated mesh layer and produced collagen. Cell viability analysis showed that most cells were viable at all experimental times. Moreover, IL-1β and IL-6 decreased, and TGF-β2 increased, in fibroblasts seeded on mesh layer coated with Ag/SiO 2 versus that without Ag/SiO 2 . Ag/SiO 2 -coated mesh layers allowed fibroblast growth and activity, without inducing cell death via apoptosis or necrosis and, at the same time, provided antibacterial activity. [ABSTRACT FROM AUTHOR]