In haemodialysis patients, the risk of bacteremia associated to the use of vascular access is very high; many reports count the use of both tunnelled and not tunnelled catheters as one of the major cause of infections. The use of silver in modern medicine is growing thanks to its strong biocide activity against a broad spectrum of bacteria and fungi and its good degree of biocompatibility. In this study an innovative and patented technology has been used for superficial treatment of polyurethane haemodialysis catheters with silver.

Antibacterial coatings on catheters for acute dialysis were obtained by an innovative and patented silver deposition technique based on the photo-reduction of the silver solution on the surface of catheter, with consequent formation of antibacterial silver nanoparticles. Aim of this work is the structural and morphological characterization of these medical devices in order to analyze the distribution and the size of clusters on the polymeric surface, and to verify the antibacterial capability of the devices treated by this technique against bacterial proliferation. The structure and morphology of the silver nanoparticles were investigated by using scanning and transmission electron microscopy. The antimicrobial capability of the catheters after silver deposition was confirmed by antibacterial tests with Escherichia coli. Both scanning electron microscopy analysis and antibacterial tests were performed also after washing catheters for 30 days in deionized water at 37°C, relating these data to thermogravimetric analysis and to energy dispersive spectroscopy, in order to check the resistance of coating and its antimicrobial capability after the maximum time of life of these devices.

In the public transport system, hand-touch surfaces such as seats in buses, trains, trams, and airplanes represent a reservoir of bacteria and a potential risk for contamination among passengers. The antimicrobial activity of silver has been known since ancient times. In this work, natural leather commonly used in the public transport system was treated with silver through the in situ photoreduction of a silver solution. The morphology of the coating and the distribution of silver clusters were studied by scanning electron microscopy and by energy dispersive X-ray spectroscopy. The amount of silver on the surface was quantified by thermo-gravimetric analysis. The antibacterial capability of the treated materials was checked against Gram-positive and Gram-negative bacteria. Taber test was conducted on silver treated samples in order to study the durability of the treatment. The morphology of the silver coating and its antibacterial capability were analyzed also after the Taber test.

Over the past several decades, a lot of emerging contaminants have been detected in water and wastewater effluents. Their release should be minimized since their presence in the environment can result in toxic effects for water and human life. Many differ- ent technologies have been used to remove contaminants from drinking water; among them, filtration is one of the most commonly used methods. This study investigated the antibacterial capability of silver water filters and their potential application in the reduction of bacterial fouling and proliferation in water treatment. Poly(ether sulfone) membranes commonly used in water filtration were coated with silver nanoparticles synthesized via the in situ photoreduction method. The morphology of the coating and the distribu- tion of silver clusters were studied by scanning electron microscopy. The amount of silver on the surface was quantified by thermog- ravimetric analysis, and the silver released from the substrate was analyzed through inductively coupled plasma mass spectrometry. The antibacterial capability of the silver-treated filters was demonstrated through microbiological tests defined for the specific applica- tion on Escherichia coli, as the representative coliform bacterium and pathogenic microorganism commonly associated with contami- nated drinking water.

Over the last few years different antibacterial technologies have been developed in order to obtain fabrics and fibers with antibacterial capabilities for use in hospital environments. High levels of sanitation are indeed required in order to reduce nosocomial cross-transmission of infections. Silver-coated fibers are particularly appealing for the production of antibacterial textiles, due to the outstanding properties of silver, characterized by a high degree of biocompatibility, an excellent resistance to sterilization conditions, and antibacterial properties with respect to different bacteria, associated with long-term efficiency. In this study an innovative patented low-cost technique to deposit silver on natural and synthetic substrates has been exploited to obtain silver-coated natural fibers (i.e. cotton and flax). Such natural fibers are largely used in the hospitals for the production of sheets, pillowcases and other textile products that should possess high levels of sanitation. The structure and morphology of the silver nanoclusters deposited onto natural fibers was observed by scanning electron microscopy (SEM), and the coating was quantitatively assessed by thermogravimetric analysis (TGA). Good silver coating stability resulted from several industrial washings performed on the samples. The antimicrobial capabilities of the treated fibers were confirmed by antibacterial tests with Escherichia Coli. Silver-coated natural fibers thus show potential for the development of antibacterial textiles with long-term efficiency that is particularly useful in healthcare settings.

This study is aimed at the synthesis of antimicrobial hydroxyapatite (HAP)‐based composites for dental application by stereolithography (SLA). A micron‐sized commercial HAP was modified by methacrylate and quaternary ammonium salt, and, then, it was used in different amounts (namely 2.5, 5, and 10 wt%) as filler for a photocurable custom made resin for SLA. Thermal stability, microstructure, and particles size of the pristine (HAP) and modified HAP (mHAP) were evaluated by thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and particle size analyser (CILAS). The suitability of each formulation for stereolithography process was assessed by measuring viscosity, degree of conversion (DC%) by Fourier transform infrared spectroscopy (FTIR), glass transition temperature, and thermal stability. Photo‐cured specimens for physical, mechanical, and antimicrobial testing were built by SLA. The flexural strength of the samples was measured using a 3‐point bending test method, and the fractured surface was analysed by scanning electron microscopy (SEM). The antimicrobial activity of samples was investigated against some standard microorganisms (Staphylococcus aureus, Escherichia coli, and Candida albicans), as representative Gram positive and Gram negative bacteria and fungus, respectively. The flexural strength increased with a filler content up to 5% and slightly decreased for higher content. SEM analysis confirmed the presence of uniformly distributed HAP. The incorporation of mHAP reduced the bacterial and fungal growth in dose‐dependent manner in comparison with the neat samples. Finally, a prototype of dental bite was built by SLA.

The defense mechanism of crops associated with the use of polymeric nets and fabrics is only physical and, hence, ineffective against the bacterial contaminations. The presence of an antibacterial agent associated with the use of conventional agro-textiles can represent a great advantage in the prevention of plant diseases and for food safety. The aim of this work was the development of antibacterial silver-coated HDPE nets for an innovative application such as agriculture. Antibacterial coatings on high-density polyethylene nets were obtained by a patented nanosilver deposition technique based on the in situ photo-reduction of a silver solution. The concentration of silver deposited was defined by testing different silver solutions from a biological point of view. Moreover, in order to improve the adhesion of the silver coating to the substrate, the nets underwent low-pressure plasma treatment before the silver deposition. The materials were characterized in terms of quality of the coating through scanning electron microscopy, and in terms of antibacterial capability on Gram positive and Gram negative bacteria through qualitative and quantitative microbiological tests. The most effective process parameters were defined and the importance of performing plasma pretreatment on this specific substrate was assessed.

The development of silver-coated polyurethane filters as filtration units for the prevention of the respiratory diseases. Methods and Results: An innovative silver deposition technology based on the photo-reduction in a silver salt was adopted. The efficacy of the technology in providing a homogeneous distribution of the silver particles was verified by scanning electron microscopy and energy dispersive X-ray spectroscopy. The materials were tested through microbiological procedures used in industry to verify the efficacy of the silver-coated filters on the viability and growth of selected micro-organisms. Direct inoculation test, filtration experiment and shaking tests were performed on microbial human pathogens associated with air filtration units and respiratory disease, namely Legionella pneumophila, Pseudomonas aeruginosa, Aspergillus niger and Aspergillus flavus, by adopting Escherichia coli and Staphylococcus aureus as control organisms. Conclusions: The results provided evidence of the effectiveness of the silver coating in reducing the bioaerosolization of viable human pathogens into environments using recirculated air. Significance and Impact of the Study: Micro-organisms can affect the air quality in indoor environments and can be responsible for infectious, allergic or toxic disturbances on human airways. The development of an adequate bioaerosol control might ameliorate a positive health effect in humans.

Hyperhidrosis, or excessive sweating, is an overlooked and potentially disabling symptom, which is often seen in social anxiety disorder. In this work an innovative advanced textile material was developed for application in the management of excessive sweating, preparing a drying yarn providing improved comfort. Hybrid cotton/hydrogel yarns were obtained by combining cotton with superabsorbent hydrogels through an optimization study focused on the achievement of the most promising product in terms of absorption properties and resistance to washings. Swelling and washing tests were performed using different hydrogels, and the effect of an additional crosslinking on the materials was also evaluated by testing different solutions containing Al(3+) and Ca(2+) ions. Scanning electron microscopy and infrared spectroscopy analyses were adopted to characterize morphology and chemical structure of the hydrogels undergoing different production processes. The biocompatibility of the hybrid fabrics was demonstrated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay (MTT) through the extract method.

The infections give rise to a range of clinical problems and prolong hospitalization with increased healthcare costs. Moreover, persistent infections exasperate the problem of antibiotic resistance. The aim of this study was the development of effective and low-cost antibacterial silver coatings on surgical sutures by adopting an innovative photochemical deposition process to prevent early contamination of surgical wounds. The silver deposition technology adopted in this work is an innovative process based on the in situ photoreduction of a silver solution. The samples were dipped in the silver solution and then exposed to UV radiation in order to induce the synthesis of silver clusters on the surface of the suture. The homogeneous distribution of silver particles on the surface and on the cross-section of the treated sutures was demonstrated. All the antibacterial studies clearly demonstrated that the use of novel silver treated sutures could represent clinical advantages in terms of the prevention of surgical infections against bacterial colonization. The silver coating deposited on the sutures demonstrated no cytotoxic effect on a selected cell population. The results obtained suggested that the antibacterial silver-coated sutures developed in this work could represent an interesting alternative to conventional sutures, with evident advantages in terms of prevention of the surgical infections and on the health costs. In addiction, very low concentrations of silver significantly inhibited the microbial load, without affecting the cell viability.

The resistance demonstrated by many microorganisms towards conventional antibiotics has stimulated the interest in alternative antimicrobial agents and in novel approaches for prevention of infections. Silver, a natural braod-spectrum antimicrobial agent known since antiquity, has been widely employed in biomedical field due to its recognized antibacterial, antifungal and antiviral properties. In this work, antibacterial silver coatings were deposited on absorbable surgical sutures through the in situ photo-chemical deposition of silver clusters. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and thermo-gravimetric analysis (TGA) were performed in order to investigate the presence and distribution of the silver clusters on the substrate. The amounts of silver deposited and released by the silver treated sutures were calculated through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS), and the results were related to the biodegradation of the material. The microbiological properties and the potential cytotoxicity of the silver-treated sutures were investigated in relation with hydrolysis experiments, in order to determine the effect of the degradation on antibacterial properties and biocompatibility.

The growing resistance of many strains of bacteria to antibiotics and antiseptics is becoming a serious problem in medicine. Nano-silver is one of the most prominent products in medicine because it exhibits unusual physicochemical properties and a strong biological activity. In this work an innovative silver deposition technology was applied to temporary polyurethane catheters for haemodialysis. The working conditions of catheters were reproduced through laboratory equipment that ensured the flow of deionized water and simulated body fluid inside the lumina at corporeal temperature. The growth and the adhesion of Staphylococcus aureus on the surface of the device were studied through fluorescence microscopy. ICP-AES was adopted to calculate the amount of silver released from the substrate. The stability of the coating during the whole working life of the device was demonstrated through thermo-gravimetric analysis.

Surface engineering based on the application of silver nanoparticles is emerging as one of the most promising in the nanotechnology field. The well-known antimicrobial activity of silver is emphasized by the high specific surface which grows inversely to the particle dimensions. In this chapter, various properties and applications of antibacterial silver coating are reviewed. In particular, an innovative deposition technology of silver nanoclusters on various natural and synthetic substrates developed by the authors is described. The deposition of strongly adhered silver nanostructures was obtained by a wet chemical method followed by a UV curing process. A very close view of the microstructure of the silver nanoclusters on the coated substrates has been obtained using advanced diagnostic tools: TEM, SEM, EDX. The strong antimicrobial capabilities of the treated substrates was evidenced with systematic antibacterial tests with Escherichia coli.

Multidrug-resistant organisms are increasingly implicated in acute and chronic wound infections, thus compromising the chance of therapeutic options. The resistance to conventional antibiotics demonstrated by some bacterial strains has encouraged new approaches for the prevention of infections in wounds and burns, among them the use of silver compounds and nanocrystalline silver. Recently, silver wound dressings have become widely accepted in wound healing centers and are commercially available. In this work, novel antibacterial wound dressings have been developed through a silver deposition technology based on the photochemical synthesis of silver nanoparticles. The devices obtained are completely natural and the silver coatings are characterized by an excellent adhesion without the use of any binder. The silver-treated cotton gauzes were characterized through scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA) in order to verify the distribution and the dimension of the silver particles on the cotton fibers. The effectiveness of the silver-treated gauzes in reducing the bacterial growth and biofilm proliferation has been demonstrated through agar diffusion tests, bacterial enumeration test, biofilm quantification tests, fluorescence and SEM microscopy. Moreover, potential cytotoxicity of the silver coating was evaluated through 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay (MTT) and the extract method on fibroblasts and keratinocytes. Inductively coupled plasma mass spectrometry (ICP-MS) was performed in order to determine the silver release in different media and to relate the results to the biological characterization. All the results obtained were compared with plain gauzes as a negative control, as well as gauzes treated with a higher silver percentage as a positive control.

Silver nanoparticles (AgNPs) have attracted intensive research interest and have been recently incorporated in polymers, medical devices, hydrogels and burn dressings to control the proliferation of microorganisms. In this study a novel silver antibacterial coating was deposited for the first time on hydrogel fibers through an in-situ photo-chemical reaction. Hydrogel blends obtained by mixing different percentages of silver-treated and untreated fibers were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Four different fluids, such as phosphate buffered saline (PBS), simulated body fluid (SBF), chemical simulated wound fluid (cSWF), and deionized water (DI water), were used for evaluating the swelling properties. The results obtained confirmed that the presence of silver did not affect the properties of the hydrogel. Moreover, the results obtained through inductively coupled plasma mass spectrometry (ICP-MS) demonstrated very low silver release values, thus indicating the perfect adhesion of the silver coating to the substrate. Good antibacterial capabilities were demonstrated by any hydrogel blend on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) through agar diffusion tests and optical density readings.

Antimicrobial copper nanoparticles (CuNPs) were electrosynthetized and applied to the controlled impregnation of industrial polyurethane foams used as padding in the textile production or as filters for air conditioning systems. CuNP-modified materials were investigated and characterized morphologically and spectroscopically, by means of Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The release of copper ions in solution was studied by Electro-Thermal Atomic Absorption Spectroscopy (ETAAS). Finally, the antimicrobial activity of freshly prepared, as well as aged samples—stored for two months—was demonstrated towards different target microorganisms.

The interest in nanotechnology and the growing concern for the antibiotic resistance demonstrated by many microorganisms have recently stimulated many efforts in designing innovative biomaterials and substrates with antibacterial properties. Among the implemented strategies to control the incidence of infections associated with the use of biomedical device and implants, interesting routes are represented by the incorporation of bactericidal agents onto the surface of biomaterials for the prevention of bacterial adhesion and biofilm growth. Natural products and particularly bioactive metals such as silver, copper and zinc represent an interesting alternative for the development of advanced biomaterials with antimicrobial properties. This review presents an overview of recent progress in the modification of biomaterials as well as the most attractive techniques for the deposition of antimicrobial coatings on different substrates for biomedical application. Moreover, some research activities and results achieved by the authors in the development of antibacterial materials are also presented and discussed.

The use of fabrics with antibacterial properties for commodity applications can provide numerous advantages such as a reduction in the release of odors due to bacterial proliferation in sweat and a reduction in the development of skin hypersensitivity reactions due to microorganisms trapped into the fabrics. Silver is one of the most effective antibacterial agents used for the high degree of biocompatibility and for its long-term antibacterial effectiveness against many different bacterial strains. In this study, an innovative technique for the deposition of nanosilver antibacterial coating on woolen fiber was analyzed. In particular, fabrics woven with different percentages of silver-treated fibers were compared to determine the best ratio preserving the antibacterial activity and optimizing the cost-effectiveness of the final product. Scanning electron microscopy revealed a uniform distribution of silver nanoclusters on the fibers. The impressive silver coating stability and durability were demonstrated after several washing cycles through thermogravimetric analysis. The antimicrobial activity of the silver-treated substrates was evaluated by antibacterial tests on Escherichia coli. A very strong antibacterial activity was found even in presence of the lower silver content; therefore, a blend of coated and uncoated fibers is proposed for practical applications.

The development of antibacterial coatings is of great interest from both industry and the consumer's point of view. In this study, we characterized tanned leather and polyurethane leatherette, typically employed in the automotive and footwear industries, which were modified by photo-deposition of antibacterial silver nanoparticles (AgNPs). Material surface chemical composition was investigated in detail by X-ray photoelectron spectroscopy (XPS). The material's antibacterial capability was checked against Escherichia coli and Staphylococcus aureus, as representative microorganisms in cross transmissions. Due to the presence of silver in a nanostructured form, nanosafety issues were considered, as well. Ionic release in contact media, as well as whole nanoparticle release from treated materials, were quantitatively evaluated, thus providing specific information on potential product nanotoxicity, which was further investigated through cytocompatibility MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, also after surface abrasion of the materials. The proved negligible nanoparticle release, as well as the controlled release of antibacterial ions, shed light on the materials' potentialities, in terms of both high activity and safety.

Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag2O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production.

Method for treatment of mulberry leaves for feeding silkworms in order to obtain a feedstuff for silkworms, doped with at least a metal selected among silver and/or zinc, comprising the steps of: a. preparing a solution comprising water, a photo- reducer agent and a precursor of said at least metal; b. treating said mulberry leaves with said solution; c. exposing said treated mulberry leaves to UV radiation, so that the photo-reduction of said precursor of said at least metal occurs, with the consequent deposition on said leaves of nanoparticles of said at least metal.

The present invention provides methods for inhibiting or preventing cancer cell growth using silver nanoparticles

Process to obtain antibacterial surfaces by silver deposition in the form of firmly bonded small particles and to the antibacterial substances obtained by aforementioned treatments. Silver deposition is obtained by surface impregnation of natural or synthetic material in an alcoholic solution with silver salt and, later, by their exposure to UV-rays until metal silver clusters form as a result of silver ions reduction on the material surface. The invention relates to the obtained antibacterial substances. The simple preparation of the antibacterial material makes the whole process easier both for required time and for costs: the needed devices are just a UV lamp and an Ultrasound bath.

Production of natural or synthetic yarns with heat transmission barrier property, obtained by deposition of non-hypercritical synthesized aerogel. Characterized by high porosity, the aerogel confers to the yarn thermal insulation properties. This enables the production of fabrics which can be utilized, as an example, under hot and cold extreme conditions. The invention is characterized by a new technique of aerogel non-hypercritical synthesis and by a process of aerogel deposition by impregnation and then yarn exposition to the UV-rays.

Production of yarns able to absorb the sweat, by introduction of super absorbent material (hydrogel) inside the yarn itself, and eventually to release perfume, previously absorbed inside the hydrogel. The super absorbent hydrogel are reticulated polymers, able to absorb up to 2 litre of water per gram of dry material. Production of yarns able to absorb the sweat, by introduction of super absorbent material (hydrogel) inside the yarn itself, and eventually to release perfume, previously absorbed inside the hydrogel. Hydrogel sweat absorption increases the comfort, since the sportsman hangover sensation is often due to the sweat direct contact with the skin. Once washed and dried, the fabric realized with such a yarn is ready for reuse, because the hydrogel absorption characteristics are fully reversible and remain even after the washing. Moreover the hydrogel is able to absorb the perfume of the washing soap and, thanks to its nature, to keep it for a long time and to release it slowly.

Production of natural or synthetic yarns with heat transmission barrier property, obtained by deposition of non-hypercritical synthesized aerogel. Characterized by high porosity, the aerogel confers to the yarn thermal insulation properties. This enables the production of fabrics which can be utilized, as an example, under hot and cold extreme conditions. The invention is characterized by a new technique of aerogel non-hypercritical synthesis and by a process of aerogel deposition by impregnation and then yarn exposition to the UV-rays.

Production of yarns able to absorb the sweat, by introduction of super absorbent material (hydrogel) inside the yarn itself, and eventually to release perfume, previously absorbed inside the hydrogel. The super absorbent hydrogel are reticulated polymers, able to absorb up to 2 litre of water per gram of dry material. Production of yarns able to absorb the sweat, by introduction of super absorbent material (hydrogel) inside the yarn itself, and eventually to release perfume, previously absorbed inside the hydrogel. Hydrogel sweat absorption increases the comfort, since the sportsman hangover sensation is often due to the sweat direct contact with the skin. Once washed and dried, the fabric realized with such a yarn is ready for reuse, because the hydrogel absorption characteristics are fully reversible and remain even after the washing. Moreover the hydrogel is able to absorb the perfume of the washing soap and, thanks to its nature, to keep it for a long time and to release it slowly.