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Sant'Ambrogio di Torino, Italy

Ferraris M.,Polytechnic University of Turin | Perero S.,Polytechnic University of Turin | Miola M.,Polytechnic University of Turin | Ferraris S.,Polytechnic University of Turin | And 4 more authors.
Advanced Engineering Materials | Year: 2010

Silver nanocluster-silica matrix composite coatings have been deposited by radio frequency (RF) co-sputtering on silica substrates. Field emission scanning electron microscopy and X-ray diffraction spectra of the as deposited and heated samples (150-600 °C) revealed the presence of metal silver nanoclusters, their size depending on the heating treatment. The antibacterial activity of the as deposited and heated samples has been measured in accordance to National Committee for Clinical Laboratory Standards, and it has been demonstrated on samples heated up to 450 °C in contact mode and for samples heated at 600 °C in a liquid environment. Their antibacterial activity was still present after gamma ray and ethylene oxide gas (EtO) sterilization of the samples. Silver leaching tests on the as deposited and heated samples has been measured by graphite furnace atomic absorption spectrometer, revealing an amount ranging from 0.1 to 0.9mg mm±2, over 28 days. Tape resistance (ASTM D3359-97) and scratch resistance tests have been done on each sample revealing a good adhesion of the coatings on silica. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Miola M.,Polytechnic University of Turin | Fucale G.,Chemical | Maina G.,University of Turin | Verne E.,Polytechnic University of Turin
Biomedical Materials (Bristol) | Year: 2015

A bioactive silica-based glass powder (SBA2) was doped with silver (Ag+) ions by means of an ion-exchange process. Scanning electron microscopy (SEM), energy dispersion spectrometry (EDS) and x-ray diffraction (XRD) evidenced that the glass powder was enriched with Ag+ ions. However, a small amount of Ag2CO3 precipitated with increased Ag concentrations in the exchange solution. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Ag-SBA2 towards Staphylococcus aureus were also evaluated and were respectively 0.05 mg ml-1 and 0.2 mg ml-1. Subsequently, Ag-SBA2 glass was used as filler (30%wt) in a commercial formulation of bone cement (Simplex™ P) in order to impart both antibacterial and bioactive properties. The composite bone cement was investigated in terms of morphology (using SEM) and composition (using EDS); the glass powder was well dispersed and exposed on the cement surface. Bioactivity tests in simulated body fluid (SBF) evidenced the precipitation of hydroxyapatite on sample surfaces. Composite cement demonstrated antibacterial properties and a compressive strength comparable to the commercial formulation. © 2015 IOP Publishing Ltd.

Miola M.,Polytechnic University of Turin | Bistolfi A.,University of Turin | Valsania M.C.,University of Turin | Bianco C.,University of Turin | And 2 more authors.
Materials Science and Engineering C | Year: 2013

An in vitro study was carried out in order to investigate the antibiotic release mechanism and the antibacterial properties of commercially (Palacos® R + G and Palacos® LV + G) and manually (Palacos® R + GM and Palacos® LV + GM) blended gentamicin-loaded bone cements. Samples were characterized by means of scanning electron microscopy (SEM) and compression strength was evaluated. The antibiotic release was investigated by dipping sample in simulated body fluid (SBF) and periodically analyzing the solution by means of high pressure liquid chromatography (HPLC). Different antibacterial tests were performed to investigate the possible influence of blending technique on antibacterial properties. Only some differences were observed between gentamicin manually added and commercial ones, in the release curves, while the antibacterial effect and the mechanical properties seem to not feel the blending technique. © 2013 Elsevier B.V.

Balagna C.,Polytechnic University of Turin | Perero S.,Polytechnic University of Turin | Ferraris S.,Polytechnic University of Turin | Miola M.,Polytechnic University of Turin | And 7 more authors.
Materials Chemistry and Physics | Year: 2012

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 ®. © 2012 Elsevier B.V. All rights reserved.

Miola M.,Polytechnic University of Turin | Bruno M.,Polytechnic University of Turin | Maina G.,University of Turin | Fucale G.,Chemical | And 2 more authors.
Materials Science and Engineering C | Year: 2014

Two bone cements (Palacos R® and Palacos LV®) based on polymethylmethacrylate (PMMA), clinically used in several cemented prosthetic devices, have been enriched with silver containing bioactive glass powders and compared with the plain commercial ones. The obtained composite cements have been subjected to a preliminary characterization by means of morphological and compositional analyses, compression mechanical tests, bioactivity test (by soaking into simulated body fluids), leaching tests and in vitro antibacterial test (count of colonies forming units, McFarland index evaluation, inhibition zone evaluation). The glass powders appeared uniformly dispersed inside the PMMA matrix and good mechanical properties (in compression) have been reached. The composite cements showed a bioactive behavior (since they developed hydroxyapatite on their surface after soaking in simulated body fluid) and a good antibacterial performance. The release of silver ions, which is the principal reason of antibacterial properties, is mainly reached after the first hours of contact with the leaching solution, as it is expected for a reasonable prevention of bacterial colonization during in vivo applications. © 2014 Published by Elsevier B.V.

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