Traumatic spinal cord injury (SCI) is a damage to the spinal cord that results in loss or impaired motor and/or sensory function. SCI is a sudden and unexpected event characterized by high morbidity and mortality rate during both acute and chronic stages, and it can be devastating in human, social and economical terms. Despite significant progresses in the clinical management of SCI, there remain no effective treatments to improve neurological outcomes. Among experimental strategies, bioengineered scaffolds have the potential to support and guide injured axons contributing to neural repair. The major aim of this study was to investigate a novel composite type I collagen scaffold with micropatterned porosity in a rodent model of severe spinal cord injury. After segment resection of the thoracic spinal cord we implanted the scaffold in female Sprague-Dawley rats. Controls were injured without receiving implantation. Behavioral analysis of the locomotor performance was monitored up to 55 days postinjury. Two months after injury histopathological analysis were performed to evaluate the extent of scar and demyelination, the presence of connective tissue and axonal regrowth through the scaffold and to evaluate inflammatory cell infiltration at the injured site. We provided evidence that the new collagen scaffold was well integrated with the host tissue, slightly ameliorated locomotor function, and limited the robust recruitment of the inflammatory cells at the injury site during both the acute and chronic stage in spinal cord injured rats. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

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.

Crosslinking and denaturation were two variables that deeply affected the performance of collagen-based scaffolds designed for tissue regeneration. If crosslinking enhances the mechanical properties and the enzymatic resistance of collagen, while masking or reducing the available cell binding sites, denaturation has very opposite effects, as it impairs the mechanical and the enzymatic stability of collagen, but increases the number of exposed cell adhesive domains. The quantification of both crosslinking and denaturation was thus fundamental to the design of collagen-based scaffolds for selected applications. The aim of this work was to investigate the extents of crosslinking and denaturation of collagen-based films upon dehydrothermal (DHT) treatment, that is, one of the most commonly employed methods for zero-length crosslinking that shows the unique ability to induce partial denaturation. Swelling measurements, differential scanning calorimetry, Fourier transform infrared spectroscopy, colorimetric assays for the quantification of primary amines, and mechanical tests were performed to analyze the effect of the DHT temperature on crosslinking and denaturation. In particular, chemically effective and elastically effective crosslink densities were evaluated. Both crosslinking and denaturation were found to increase with the DHT temperature, although according to different trends. The results also showed that DHT treatments performed at temperatures up to 120°C maintained the extent of denaturation under 25%. Coupling a mild DHT treatment with further crosslinking may thus be very useful not only to modulate the crosslink density, but also to induce a limited amount of denaturation, which shows potential to partially compensate the loss of cell binding sites caused by crosslinking. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 186-194, 2016.

Autologous nerve grafting is the current gold standard treatment for peripheral nerve injury, in cases where direct suturing of nerve ends is not possible. Even though the functional restoration achieved by the autograft is not optimal, autologous nerve tissues still show higher regenerative capability than several synthetic conduits available in the clinical setting, the latter used only for gaps that do not exceed 3 cm in length. The aim of this chapter is to highlight how bio-mimicry, inspired by nerve development, structure and spontaneous regeneration following mild nerve injury, can help in the design of synthetic templates with optimized bioactivity for nerve regeneration.

A porous collagen-based hydrogel scaffold was prepared in the presence of iron oxide nanoparticles (NPs) and was characterized by means of infrared spectroscopy and scanning electron microscopy. The hybrid scaffold was then loaded with fluorescein sodium salt as a model compound. The release of the hydrosoluble species was triggered and accurately controlled by the application of an external magnetic field, as monitored by fluorescence spectroscopy. The biocompatibility of the proposed matrix was also tested by the MTT assay performed on 3T3 cells. Cell viability was only slightly reduced when the cells were incubated in the presence of the collagen-NP hydrogel, compared to controls. The economicity of the chemical protocol used to obtain the paramagnetic scaffolds as well as their biocompatibility and the safety of the external trigger needed to induce the drug release suggest the proposed collagen paramagnetic matrices for a number of applications including tissue engeneering and drug delivery.

Physical foaming combined with microwave-induced curing was used in this study to develop an innovative device for bone tissue regeneration. In the first step of the process, a stable physical foaming was induced using a surfactant (i.e. pluronic) as blowing agent of a homogeneous blend of Sodium salt of carboxymethylcellulose (CMCNa) and polyethylene glycol diacrylate (PEGDA700) solution. In the second step, the porous structure of the scaffold was chemically stabilized by radical polymerization induced by a homogeneous rapid heating of the sample in a microwave reactor. In this step 2,2-Azobis[2-(2-imidazolin-2 yl)propane]Dihydrochloride was used as thermoinitiator (TI). CMCNa and PEGDA were mixed with different blends to correlate the properties of final product with the composition. The chemical properties of each sample were evaluated by spectroscopy analysis ATR-IR (before and after curing) in order to maximize reaction yield, and optimize kinetic parameters (i.e. time curing, microwave power). The stability of the materials was evaluated in vitro by degradation test in Phosphate Buffered Saline (PBS). Biological analyses were performed to evaluate the effect of scaffold materials on cellular behaviour in terms of proliferation and early osteogenic differentiation of human Mesenchymal Stem Cells (hMSC). This article is protected by copyright. All rights reserved.

Large bone or osteochondral defects still need new approaches to ameliorate the regeneration process. The integration of magnetic nanoparticles into synthetic/natural scaffold formulations, could lead to obtain a suitable, responsive “on demand” tool able to guide the regeneration process. The aim of this work was the design and characterization of chitosan-based scaffolds containing dextran-grafted maghemite (DM) with modular mechano-structural and biomimetic properties implemented by the presence of a bioactive agent such the L-arginine amino acid. Both components can act as modulators of the scaffold features and, at the same time, the simultaneous presence of MNPs and L-Arg can be exploited to induce variations with respect to the cytocompatibility responses.

This study (i) developed a scaffold made of collagen I designed for hosting the autologous chondrocytes, (ii) focused on the optimization of chondrocytes seeding by the addition of the fibrin glue, and (iii) investigated the culture time for the ideal scaffold maturation in vitro. In the first part of the study, fresh chondrocytes were isolated from infant swine articular cartilage, and immediately seeded onto the collagen sponges either in medium or in fibrinogen in order to show the contribute of fibrin glue in cell seeding and survival into the scaffold. In the second part of the study, chondrocytes were first expanded in vitro and then resuspended in fibrinogen, seeded in collagen sponges, and cultured for 1, 3, and 5 weeks in order to identify the optimal time for the rescue of cell phenotype and for the scaffold maturation into a tissue with chondral properties. The histological and immunohistochemical data from the first part of the study (study with primary chondrocytes) demonstrated that the presence of fibrin glue ameliorated cell distribution and survival into the chondral composites. The second part of this work (study with dedifferentiated chondrocytes) showed that the prolongation of the culture to 3 weeks promoted a significant restoration of the cell phenotype, resulting in a composite with proper morphological features, biochemical composition, and mechanical integrity. In conclusion, this study developed a collagenic-fibrin glue scaffold that was able to support chondrocyte survival and synthetic activity in a static culture; in particular, this model was able to turn the engineered samples into a tissue with chondral-like properties when cultured in vitro for at least 3 weeks.

In the last years, several tissue engineering techniques have been applied to develop different kinds of osteochondral substitutes to overcome the scarce reparative properties of this tissue. The aim of this study was to generate and compare three biphasic scaffolds in an osteochondral lesion in a large-animal model. A critical osteochondral defect was generated in the medial femoral condyle of 18 skeletally mature sheep. Three defects were left untreated, the remaining lesions were divided into three groups: 5 lesions were treated with a biphasic scaffold made of collagen type I and small cylinders of Magnesium Hydroxyapatite; 5 lesions were treated with a biphasic substituted formed by collagen type I and Wollastonite, 5 lesions were treated with a scaffold made of collagen type I and small cylinders of Wollastonite/Hydroxyapatite. Animals were sacrificed after 3 months and samples were analyzed by CT and MRI, macroscopic evaluation and histology. Our study demonstrated that one of these novel biphasic scaffolds possesses the potential for being applied for one-stage procedures for osteochondral defects.

The microstructural, mechanical, compositional, and degradative properties of a nerve conduit are known to strongly affect the regenerative process of the injured peripheral nerve. Starting from the fabrication of micropatterned collagen-based nerve guides, according to a spin-casting process reported in the literature, this study further investigates the possibility to modulate the degradation rate of the scaffolds over a wide time frame, in an attempt to match different rates of nerve regeneration that might be encountered in vivo. To this aim, three different crosslinking methods, that is, dehydrothermal (DHT), carbodiimide-based (EDAC), and glutaraldehyde-based (GTA) crosslinking, were selected. The elastically effective degree of crosslinking, attained by each method and evaluated according to the classical rubber elasticity theory, was found to significantly tune the in vitro half-life (t1/2) of the matrices, with an exponential dependence of the latter on the crosslink density. The high crosslinking efficacy of EDAC and GTA treatments, respectively threefold and fourfold when compared to the one attained by DHT, led to a sharp increase of the corresponding in vitro half-lives (ca., 10, 172, and 690 h, for DHT, EDAC, and GTA treated matrices, respectively). As shown by cell viability assays, the cytocompatibility of both DHT and EDAC treatments, as opposed to the toxicity of GTA, suggests that such methods are suitable to crosslink collagen-based scaffolds conceived for clinical use. In particular, nerve guides with expected high residence times in vivo might be produced by finely controlling the biocompatible reaction(s) adopted for crosslinking.

Three-dimensional (3D) porous scaffolds based on collagen are promising candidates for soft tissue engineering applications. The addition of stimuli-responsive carriers (nano- and microparticles) in the current approaches to tissue reconstruction and repair brings about novel challenges in the design and conception of carrier-integrated polymer scaffolds. In this study, a facile method was developed to functionalize 3D collagen porous scaffolds with biodegradable multilayer microcapsules. The effects of the capsule charge as well as the influence of the functionalization methods on the binding efficiency to the scaffolds were studied. It was found that the binding of cationic microcapsules was higher than that of anionic ones, and application of vacuum during scaffolds functionalization significantly hindered the attachment of the microcapsules to the collagen matrix. The physical properties of microcapsules-integrated scaffolds were compared to pristine scaffolds. The modified scaffolds showed swelling ratios, weight losses and mechanical properties similar to those of unmodified scaffolds. Finally, in vitro diffusional tests proved that the collagen scaffolds could stably retain the microcapsules over long incubation time in Tris-HCl buffer at 37°C without undergoing morphological changes, thus confirming their suitability for tissue engineering applications. The obtained results indicate that by tuning the charge of the microcapsules and by varying the fabrication conditions, collagen scaffolds patterned with high or low number of microcapsules can be obtained, and that the microcapsules-integrated scaffolds fully retain their original physical properties.

In the last decade cellulose-based hydrogels have been receiving increasing attention for a number of applications, due to their smart swelling behaviour, biodegradability and biocompatibility. Given the dramatic spreading of obesity and overweight in the industrialized countries and the lack of scientific consensus over currently available dietary supplements, it was recently proposed that such hydrogels might be used as orally administered bulking agents in hypocaloric diets, since the hydrogel swelling in the stomach may greatly reduce the space available for food intake, thus giving a sense of fullness. This study focused on the synthesis of cellulose-based hydrogels, starting from pharmaceutical and food grade cellulose derivatives, and showed that such hydrogels possess good swelling properties in water solutions mimicking the environmental conditions of the stomach and the intestine, as well as a good biocompatibility. The crosslinking agent used was a ‘zero-length’ crosslinker, i.e. a water soluble carbodiimide, which is washed out from the gel after the synthesis and does not affect the gel compatibility, as shown by preliminary biocompatibility assays. The experimental results confirmed that cellulosebased hydrogels might be a scientifically valid dietary adjuvant in the treatment of obesity and overweight, and provide further scientific evidence for future experiments on humans.

The need for reconstructing complex bone defects in the maxillofacial region as a result of trauma, tumor surgery or congenital malformation has become a hot topic in the field of tissue engineering. Tools such as 3D computer aided design (CAD) systems and rapid prototyping (RP) machines can be exploited to fabricate custom made bone scaffolds. RP techniques allow the construction of complex physical models based on 3D clinical images elaborated by suitable software and CAD systems. Hydroxyapatite (HA) is one of the most commonly used materials for bone reconstruction because of its close similarity in composition to human bone and teeth. Thus, producing a custom-made scaffold from a ceramic material directly by RP represents an exciting challenge. The aim of this paper is the development of a suspension of HA powder dispersed in an UV curable epoxy based resin, suitable for stereolithography (SLA). The influence of different HA concentrations within the ceramic suspension on the kinetics of the photochemical reaction was firstly investigated. The rheological behavior of the same ceramic suspensions was also analyzed by verifying the effect of HA on the viscosity and the stability of the suspensions as a function of the shear rate and the time from preparation. After the selection of a suitable suspension, simple green ceramic bars built by stereolithography and sintered with an appropriate thermal cycle, were built and characterized, showing good mechanical properties. A complex prototype, starting from a CAD model, was finally built by a SLA apparatus

In this work a novel three-dimensional ostechondral substitute is proposed that is made of an inorganic/organic hybrid material, namely collagen/hydroxyapatite. The two components of the substitute have been characterized separately. The inorganic part, a hydroxyapatite scaffold, was fabricated by a polymer sponge templating method using a reactive sub-micron powder synthesized in our laboratory by hydroxide precipitation sol-gel route. The organic part, a collagen scaffold, was fabricated by a freeze-dying technique varying design parameters. Both the parts were analysed by scanning electron microscopy and their mechanical properties assessed by compression tests. The hydroxyapatite scaffold showed a high and highly interconnected porosity and a mechanical strength equal to 0.55 MPa, higher than those reported in literature. The collagen scaffolds were seeded by chondrocytes, processed for histology analysis and tested in compression. The biological tests proved the ability of the scaffolds to be positively populated by chondrocytes and the mechanical analysis showed that the mechanical strength of the scaffolds significantly increased after 3 weeks of culture.

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.

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.

Purpose: The objective of this work was to develop composite hydrogels based on poly(ethylene glycol) diacrylate (PEGDA) and collagen (Coll), potentially useful for biomedical applications. Methods: Semi-interpenetrating polymer networks (semi-IPNs) were obtained by photo-stabilizing aqueous solutions of PEGDA and acrylic acid (AA), in the presence of collagen. Further grafting of the collagen macromolecules to the PEGDA/poly(AA) network was achieved by means of a carbodiimide-mediated crosslinking reaction. The resulting hydrogels were characterized in terms of swelling capability, collagen content and mechanical properties. Results and conclusions: The grafting procedure was found to significantly improve the mechanical stability of the IPN hydrogels, due to the establishment of covalent bonding between the PEGDA/poly(AA) and the collagen networks. The suitability of the composite hydrogels to be processed by means of stereolithography (SLA) was also investigated, toward creating biomimetic constructs with complex shapes, which might be useful either as platforms for tissue engineering applications or as tissue mimicking phantoms.

Collagen is one of the most used materials in scaffolding production; this is due to its peculiar characteristics that make the polymer highly biocompatible and efficient in regeneration induction and growth cone guidance. We aimed to investigate whether collagen could per se induce Schwann cell differentiation/proliferation and how it would do so. Results obtained in immortalized rat Schwann cells showed differential effects on several proliferation and differentiation markers depending on the type of collagen used to produce the scaffolds.

Understanding the relationships between material surface properties and cellular responses is essential to designing optimal material surfaces for implantation and tissue engineering. In this study, cellulose hydrogels were crosslinked using a non-toxic and natural component namely citric acid. The chemical treatment induces -COOH functional groups that improve the hydrophilicity, roughness, and materials rheological properties. The physiochemical, morphological, and mechanical analyses were performed to analyze the material surface before and after crosslinking. This approach would help determine if the effect of chemical treatment on cellulose hydrogel improves the hydrophilicity, roughness, and rheological properties of the scaffold. In this study, it was demonstrated that the biological responses of human mesenchymal stem cell with regard to cell adhesion, proliferation, and differentiation were influenced in vitro by changing the surface chemistry and roughness.

Dehydrothermal (DHT) crosslinking is routinely performed to increase the stiffness and the enzymatic resistance of collagen-based devices. Amide and ester bonds are formed among the collagen macromolecules, as a result of the high temperatures and high vacuum involved in the process. The extent of crosslinking is known to increase with the DHT temperature and duration, but simultaneous collagen denaturation might be induced. The aim of this work was to investigate the extent of crosslinking and denaturation of DHT-treated collagen-based films, by means of thermal and physicochemical analyses. With the ultimate goal of optimizing the DHT process, five different temperatures (110, 120, 140, 160 and 180°C) were used, while the DHT duration was kept constant (24 hours). Differential scanning calorimetry (DSC) was carried out to measure the denaturation temperature (Td) and enthalpy (ΔHd) of the collagen films. The reaction of 2,4,6-trinitrobenzenesulfonic acid (TNBS) with primary amines (-NH2) allowed determining the number of free -NH2 in the collagen films, whereas Fourier transform infrared spectroscopy (FTIR) was used to investigate the chemical modifications occurring upon DHT treatment. Higher degrees of crosslinking were attained for increasing DHT temperatures, as demonstrated by reduced number of free -NH2, lower absorbance of amide II band (1545 cm-1) and higher Td values. However, the sharp reduction of ΔHd detected for samples treated at 140, 160 and 180°C indicated a significant denaturation associated to crosslinking. The analysis of the absorbance band at 1236 cm-1 confirmed that collagen denaturation was particularly pronounced for DHT temperatures higher than 120°C, suggesting that, at those temperatures, denaturation might predominate over crosslinking. Further stress relaxation tensile tests and dynamic mechanical analysis (DMA) are currently being performed to measure the stiffness of DHT-treated samples and to estimate the elastically effective crosslink density, according to the rubber elasticity theory.

The aim of this work was to investigate the structural features of type I collagen isoforms and collagen-based films at atomic and molecular scales, in order to evaluate whether and to what extent different protocols of slurry synthesis may change the protein structure and the final properties of the developed scaffolds. Wide Angle X-ray Scattering data on raw materials demonstrated the preferential orientation of collagen molecules in equine tendon-derived collagens, while randomly oriented molecules were found in bovine skin collagens, together with a lower crystalline degree, analyzed by the assessment of FWHM (Full Width at Half Maximum), and a certain degree of salt contamination. WAXS and FT-IR (Fourier Transform Infrared) analyses on bovine collagen-based films, showed that mechanical homogenization of slurry in acidic solution was the treatment ensuring a high content of super-organization of collagen into triple helices and a high crystalline domain into the material. In vitro tests on rat Schwannoma cells showed that Schwann cell differentiation into myelinating cells was dependent on the specific collagen film being used, and was found to be stimulated in case of homogenization-treated samples. Finally DHT/EDC crosslinking treatment was shown to affect mechanical stiffness of films depending on collagen source and processing conditions.

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.

Alginate micro beads containing Lactobacillus kefiri (the principal bacteria present in the kefir probiotic drink) were produced by a novel technique based on dual aerosols spaying of alginate based solution and CaCl2 as cross linking agent. Carboxymethylcellulose (CMC) has been also added to the alginate in order to change the physic-chemical properties (viscosity and permeability) of the microbeads. Calcium alginate and CMC are biopolymers that can be used for developing oral drug-delivery systems. These biopolymers have been reported to show a pH-dependent swelling behaviour. Calcium alginate and CMC have also been known to possess an excellent mucoadhesive property. The loaded microbeads have been characterized in terms of morphology, chemical composition and stability in different conditions mimicking the gastric environment. In this study, we demonstrate the feasibility of a continuous fabrication of alginate microbeads in a range of 50–70 μm size, encapsulating L. kefiri as active ingredient. The technique involves the use of a double aerosols of alginate based solution and CaCl2 as crosslinking agent. Moreover, the encapsulation process was proved to be effective and not detrimental to bacteria viability. At the same time, it was verified the protective efficacy of the microcapsules against the gastric environment using both SGF pH 1.2 (fasted state) and pH 2.2 (feed state).

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.

The development of biocompatible collagen substrates able to conduct electric current along specific pathways represent an appealing issue in tissue engineering, since it is well known that electrical stimuli significantly affects important cell behaviour, such as proliferation, differentiation, directional migration, and, therefore, tissue regeneration. In this work, a cheap and easy approach was proposed to produce collagen-based films exhibiting enhanced electrical conductivity, through the simple manipulation of a weak external magnetic trigger. Paramagnetic iron oxide nanoparticles (NPs) capped by a biocompatible polyethylene-glycol coating were synthetized by a co-precipitation and solvothermic method and sprayed onto a collagen suspension. The system was then subjected to a static external magnetic field in order to conveniently tune NPs organization. Under the action of the external stimulus, NPs were induced to orient along the magnetic field lines, forming long-range aligned micropatterns within the collagen matrix. Drying of the substrate following water evaporation permanently blocked the magnetic architecture produced, thereby preserving NPs organization even after magnetic field removal. Electrical conductivity measurements clearly showed that the presence of such a magnetic framework endowed collagen with marked conductive properties in specific directions. The biocompatibility of the paramagnetic collagen films was also demonstrated by MTT cell cytotoxicity test.

In this work, an innovative cellulose-based superabsorbent polymer (SAP) was experimentally assessed as an environmentally friendly alternative to acrylate-based SAPs, for the optimization of water consumption in agriculture. The cellulose-based SAP was synthesized and tested for its swelling capability in different aqueous media. The effectiveness of the SAP in agricultural applications was then evaluated by analyzing its performance after several absorption/desorption cycles, over a period of approximately 80 days, upon addition to different types of soil, i.e., white and red soil, for the cultivation of two varieties of plants typical of the Mediterranean area (tomatoes and chicory). The results confirmed that SAP-amended soil can store a considerable amount of water and can release it gradually to the plant roots when needed. The adoption of the proposed SAP in cultivations could thus represent a promising solution for the rationalization of water resources, especially in desert areas.

The development of bio-devices for complete regeneration of ligament and tendon tissues is presently one of the biggest challenges in tissue engineering. Such device must simultaneously possess optimal mechanical performance, suitable porous structure, and biocompatible microenvironment. This study proposes a novel collagen-BDDGE-elastin (CBE)-based device for tendon tissue engineering, by the combination of two different modules: (i) a load-bearing, non-porous, "core scaffold" developed by braiding CBE membranes fabricated via an evaporative process and (ii) a hollow, highly porous, "shell scaffold" obtained by uniaxial freezing followed by freeze-drying of CBE suspension, designed to function as a physical guide and reservoir of cells to promote the regenerative process. Both core and shell materials demonstrated good cytocompatibility in vitro, and notably, the porous shell architecture directed cell alignment and population within the sample. Finally, a prototype of the core module was implanted in a rat tendon lesion model, and histological analysis demonstrated its safety, biocompatibility, and ability to induce tendon regeneration. Overall, our results indicate that such device may have the potential to support and induce in situ tendon regeneration.

Poly(ethylene glycol) diacrylate (PEGDA) cryogels, particularly useful for biotechnological applications, are currently fabricated exploiting crosslinking systems that require long freezing/crosslinking times (20 h or longer). The aim of this work was to assess whether fast UV irradiation (up to 60 s) of frozen PEGDA solutions could be an advantageous alternative for cryogel production. By using different polymer concentrations and UV times, cryogels with highly interconnected macropores (about 50–90 μm) were produced. A gelation yield in the range 60–80% was recorded, with higher values obtained for low PEGDA concentrations (5 and 10% w/v). Interestingly, while decreasing the swelling and increasing the stiffness of the cryogels, a higher polymer concentration was also found to reduce the pore size. Furthermore, increasing the UV time resulted in significantly higher swelling and larger pores for 10% PEGDA samples, while having negligible effect on other cryogel types and/or features. Although deserving further exploration, fast UV irradiation is an effective method to produce PEGDA cryogels with tunable properties.

Hydroxyapatite (HA) macrochanneled porous scaffolds were produced by polymer sponge templating method using a reactive submicrometer powder synthesized by hydroxide precipitation sol–gel route. The microstructure of the fine HA powder was carefully investigated and developed in order to optimize the mechanical properties and phase stability of sintered scaffold. The templating method ensured a highly interconnected macrochanneled porous structure with over 500 μm mean pore size and 90% porosity. The high reactivity of the powder led to an efficient sintering mechanism with a high and crack-free linear shrinkage (19 ± 2%) and a significant BET specific surface area reduction (from 12 to 0.33 m2/g). The powder does not dissociate into secondary phases during sintering. Despite the extreme porosity, the scaffolds had high mechanical performance (compressive strength ∼0.51 MPa, Weibull modulus 4.15) compared with literature data and with scaffolds similarly prepared from high-quality commercial HA powder.

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.

In tissue engineering field, the production of a porous resorbable matrix, termed scaffold, allows to host cells and guide them towards the synthesis of physiological tissue. Porous scaffolds provide mechanical stability and an initial framework for migrating cells and vascular infiltration. Sustained delivery of bioactive molecules at the defect site may be also particularly important for tissue regeneration. In this context, the goal of this work was the fabrication of highly porous collagen-based scaffolds incorporating uniformly dispersed poly(lactide-co-glycolide) (PLGA) microparticles as depots for the sustained and localized delivery of bioactive molecules. Collagen scaffolds loaded with different amounts of PLGA-microparticles were prepared by freeze-drying and crosslinking. The scaffolds microstructure was assessed to evaluate the spatial distribution of microparticles and the achieved pore size. The impact of the microparticles on the scaffolds stiffness was investigated through compression tests. Preliminarily, the cell-microparticles interactions were also evaluated by imaging of cell morphology in vitro, adopting a human derived epithelial cell model. The experimental findings showed that collagen scaffolds with different amounts of uniformly dispersed PLGA-microparticles were successfully produced. The microparticles did not negatively affect the scaffold porous structure, while acting as a mechanical reinforcement. Additionally, microparticles show high permissiveness to cell adhesion, and the interactions between microparticles and epithelial cell membranes did not interfere with the correct cells morphological differentiation. Such promising results suggest the potential of the developed scaffolds for tissue engineering applications.

The aim of the present work is to study the influence of the precipitation temperature in the synthesis of nanohydroxyapatite (n-HAp) on the properties of the resulting n-HAp powder for the fabrication of highly porous scaffolds for bone tissue engineering. The n-HAp powder was obtained by a wet precipitation technique starting from calcium nitrate tetrahydrate (Ca(NO3)(2)*4H(2)O) and phosphoric acid (H3PO4) at different temperatures: 10 degrees C, 37 degrees C and 50 degrees C. Highly porous scaffolds were fabricated using the three different powders by the sponge replica method and sintering at 1300 degrees C. Combined X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses on powders indicated that on increasing the precipitation temperature the formation of pure n-HAp is accelerated, without significant changes in particles morphology and size. Scaffolds characterized by high porosity (89%) and good compressive strength (0.53 MPa for n-HAp prepared at 37 degrees C) were obtained. XRD analyses on sintered n-HAp confirmed the thermal stability of the material. Therefore, the as-synthesized n-HAp powder can be successfully used for the fabrication of highly porous scaffolds as bone substitutes.

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.

A highly porous (~90%) interconnected hydroxyapatite/wollastonite (HA/WS) scaffolds were prepared by polymeric sponge replica method using a slurry containing HA:Calcium silicate in the weight ratio of 50:50 and sintered at 1300 oC. The phase purity of the scaffolds were analyzed by using XRD. The pore size, pore structure, microstructure and elemental analysis of the scaffolds before and after SBF soaking were analyzed using SEM and EDS. In-vitro bioactivity and bioresorbability confirmed the feasibility of the developed scaffolds. The HA/WS scaffold shows two fold increase in the compressive strength compared to pure HA scaffold.

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.

INTRODUCTION Peripheral nerve injuries often result in painful neuropathies owing to reduction in motor function and sensory perception. When large nerve gaps exist (20mm or longer in humans), sensory nerve autografts are conventionally used to treat neural defects. The main issues related to autografts are shortage of donor nerves, a mismatch of donor nerve size with the recipient site, and occurrences of neuroma formation. Recent advances in nanotechnology and tissue engineering have been found to cover a broad range of applications in regenerative medicine and offer the most effective strategy to repair neural defects. Prior work in this area has shown the utility of collagen-based scaffolds for the regeneration of nerve tissue. This work focuses on the fabrication of collagen scaffolds with two different pore sizes, with the aim of evaluating the effects of pore size on the migration of Schwann cell lines. EXPERIMENTAL METHODS Scaffold fabrication and crosslinking Porous cylindrical scaffolds (diameter=2mm, length=10mm) with aligned channels were fabricated by freeze-drying a 2wt% collagen suspension along a one-dimensional temperature gradient (along the length of the cylindrical scaffold). Scaffolds with two different pore sizes were fabricated by freezing the collagen suspension at two different final freezing temperatures (-20°C and -60°C). The scaffolds were then subjected to dehydrothermal (DHT) cross-linking, followed by a carbodiimide based chemical crosslinking. Qualitative characterization of the pore structure was performed by means of scanning electron microscopy (SEM). Cell culture and cytocompatibility A rat Schwann cell line, RSC96, was expanded in monolayer culture in a 96-well plate. The plate was then incubated at 37°C and 5% CO2 for 24 hours. After 24 hours, sterilized scaffolds were placed vertically to the wells of the 96-well plate and incubated again at 37°C and 5% CO2. At 1, 3, 7, and 10 days, the cell-seeded scaffolds were fixed in 10% formalin and processed for paraffin embedding. Schwann cells were quantified by embedding the cell-seeded scaffolds in paraffin blocks, sectioning, staining them with hematoxylin & eosin stain (H&E stain) and visualizing under a microscope. MTT assay was also performed at 1, 3, 7 and 10 days to evaluate the cell viability. RESULTS AND DISCUSSION SEM demonstrated that both freezing temperature and rate of freezing affect significantly the pore size. As shown in Fig.1, lower temperatures (-60°C) resulted in smaller pore sizes (~85µm), while higher temperatures (-20°C) resulted in much larger pores (~120µm). The longitudinal sections of the samples showed that the pores were in axial orientation disregard of the freezing temperature. MTT assay revealed that cell viability on the two different types of scaffolds increased gradually from first to the tenth day after seeding. Although there was not much difference between the two porous scaffolds on day 1, 3 and 7, on day 10 there was a slight increase in the cell number in the scaffolds with a larger pore size (-20°C). In spite of the different pore dimensions under investigation, the cell migration studies revealed that Schwann cells could migrate through the entire length of both types of scaffolds, by day 7. CONCLUSION Both types of scaffolds were found to support Schwann cell growth and migration, which is the key factor required for the regeneration of nerve tissue. Further studies are proposed regarding the addition of laminin and the evaluation of its effects on the cell growth and migration. REFERENCES 1. W. Daly et al., J. R. Soc. Interface 9:202-221, 2012.

In this study, a new foaming method, based on physical foaming combined with microwave-induced curing, is proposed in combination with a surface bioactivation to develop scaffold for bone tissue regeneration. In the first step of the process, a stable physical foaming was induced using a surfactant (Pluronic) as blowing agent of a homogeneous blend of Chitosan and polyethylene glycol diacrylate (PEGDA700) solutions. In the second step, the porous structure of the foaming was chemically stabilized by radical polymerization induced by homogeneous heating of the sample in a microwave reactor. In this step, 2,2-azobis[2-(2-imidazolin-2yl)propane]dihydrochloride was used as thermoinitiator (TI). Chitosan and PEGDA were mixed in different blends to investigate the influence of the composition on the final properties of the material. The chemical properties of each sample were evaluated by infrared attenuated total reflectance analysis, before and after curing in order to maximize reaction yield and optimize kinetic parameters (i.e. time curing, microwave power). Absorption capacity, elastic modulus, porosity and morphology of the porous structure were measured for each sample. The stability of materials was evaluated in vitro by degradation test in phosphate-buffered saline. To improve the bioactivity and biological properties of chitosan scaffold, a biomineralization process was used. Biological characterization was carried out with the aim to prove the effect of biomineralization scaffold on human mesenchymal stem cells behaviour. Copyright © 2016 John Wiley & Sons, Ltd.

Tubular scaffolds demonstrated to be able to reconnect the proximal and distal stumps of transected peripheral nerves and induce regeneration of the lost nerve trunk. Recently, a spinning technique has been developed, able to produce tubular collagen-based scaffolds characterized by a radially patterned microporosity. The technique is based on the centrifugal sedimentation of collagen taking place when a cylinder, containing an aqueous collagen suspension, is rotated rapidly around its axis. In this work, the centrifugation process was modeled by means of the Lamm differential equation for collagen concentration, with the assumption that sedimentation and diffusion coefficients were dependent on the local concentration, according to appropriate scaling laws. With such assumptions, the model was able to predict the actual tube formation and its inner radius, in good agreement with the experimental results. The possibility to predict the final scaffold inner diameter as a function of the processing parameters has a fundamental importance for the set up of a precise fabrication method, which does not make use of any complex mold. This would significantly reduce the production complexity and the extent of scaffold manipulation during production, resulting in a cleaner production process and safety of the device.

In this chapter, we aim at providing an up-to-date review on nerve tissue engineering, focusing on both the peripheral and the central nervous systems (PNS and CNS, respectively). After introducing the pathophysiology of nerves and the social impact of nerve injuries, we overview the therapeutic approaches oriented toward inducing nerve regeneration, involving cellular, molecular, and scaffold-based strategies. A section is dedicated specifically to the PNS, with a critical focus on the actual therapeutic potential of experimental devices for the development of tissue-engineered medical products. A case study regarding the implementation of micropatterned collagen-based conduits in a clinical trial on PNS regeneration is also presented. Another section is dedicated to the ongoing research investigating the regenerative mechanisms of the CNS. In this context, spinal cord injury is assumed as a model lesion, for which complex tissue-engineered devices are being developed, at least in animal studies. With such a structure, this chapter is intended to provide a comprehensive, though not exhaustive, overview of nerve tissue engineering, which might be useful to students, researchers, clinicians, and biomedical entrepreneurs.

A novel three-dimensional bicomponent substitute made of collagen type I and hydroxyapatite was tested for the repair of osteochondral lesions in a swine model. This scaffold was assembled by a newly developed method that guarantees the strict integration between the organic and the inorganic parts, mimicking the biological tissue between the chondral and the osseous phase. Thirty-six osteochondral lesions were created in the trochlea of six pigs; in each pig, two lesions were treated with scaffolds seeded with autologous chondrocytes (cell+group), two lesions were treated with unseeded scaffolds (cell- group), and the two remaining lesions were left untreated (untreated group). After 3 months, the animals were sacrificed and the newly formed tissue was analyzed to evaluate the degree of maturation. The International Cartilage Repair Society (ICRS) macroscopic assessment showed significantly higher scores in the cell- and untreated groups when compared with the cell+ group. Histological evaluation showed the presence of repaired tissue, with fibroblast-like and hyaline-like areas in all groups; however, with respect to the other groups, the cell- group showed significantly higher values in the ICRS II histological scores for "cell morphology" and for the "surface/superficial assessment." While the scaffold seeded with autologous chondrocytes promoted the formation of a reparative tissue with high cellularity but low glycosaminoglycans (GAG) production, on the contrary, the reparative tissue observed with the unseeded scaffold presented lower cellularity but higher and uniform GAG distribution. Finally, in the lesions treated with scaffolds, the immunohistochemical analysis showed the presence of collagen type II in the peripheral part of the defect, indicating tissue maturation due to the migration of local cells from the surroundings. This study showed that the novel osteochondral scaffold was easy to handle for surgical implantation and was stable within the site of lesion; at the end of the experimental time, all implants were well integrated with the surrounding tissue and no signs of synovitis were observed. The quality of the reparative tissue seemed to be superior for the lesions treated with the unseeded scaffolds, indicating the promising potential of this novel biomaterial for use in a one-stage procedure for osteochondral repair.

Several bioengineering approaches have been proposed for peripheral nervous system repair, with limited results and still open questions about the underlying molecular mechanisms. We assessed the biological processes that occur after the implantation of collagen scaffold with a peculiar porous microstructure of the wall in a rat sciatic nerve transection model compared to commercial collagen conduits and nerve crush injury using functional, histological and genome wide analyses. We demonstrated that within 60 days, our conduit had been completely substituted by a normal nerve. Gene expression analysis documented a precise sequential regulation of known genes involved in angiogenesis, Schwann cells/axons interactions and myelination, together with a selective modulation of key biological pathways for nerve morphogenesis induced by porous matrices. These data suggest that the scaffold's microstructure profoundly influences cell behaviors and creates an instructive micro-environment to enhance nerve morphogenesis that can be exploited to improve recovery and understand the molecular differences between repair and regeneration.

The aim of this work was to assess the diffusive properties of poly(ethylene glycol) diacrylate (PEGDA)-based hydrogels, derived from low MW prepolymers, in view of potential biomedical applications. Several hydrogels were synthesized through UV irradiation of PEGDA solutions for different exposure times. Swelling measurements in distilled water were performed to estimate the yielded crosslink density, while swelling tests at 37 °C in selected media allowed to analyze the mesh size changes induced by various pH and ionic strength (IonS) conditions. The transport of glucose and insulin through thin hydrogel membranes was finally assessed in a modified Ussing chamber at physiological values of pH and IonS (7.4 and 150 mM, respectively). Results showed that the swelling was dependent on the IonS (with swelling reductions up to 20–30% for IonS increases in the range 0–300 mM) and, to a lesser extent, on the pH of the surrounding medium (with swelling increments of about 10% for increasing pH in the range 2.5–11). All hydrogels were also permeable to glucose and insulin, which displayed comparable diffusion coefficients (in the order of 10−6 cm2/s). Specific interactions between glucose and the polymer chains were evidenced by values of the partition coefficient higher than unity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44380. © 2016 Wiley Periodicals, Inc.

The aim of this work was the superficial activation, by means of plasma treatments, of crosslinked collagen-based scaffolds for nerve regeneration, in order to immobilize anionic and cationic microcapsules (MCPs) for drug delivery. Matrices with axially oriented pores have the potential to improve the regeneration of peripheral nerves and spinal cord by physically supporting and guiding the growth of neural structures across the site of injury. To improve mechanical resistance and stability in water solutions, it is necessary to crosslink collagenous fibres by formation of amide bonds with consequent reduction of free amino and carboxylic groups useful for immobilization approach of drug delivery systems like MCPs. Plasma chemical processes represent a successful approach because allow polar groups to be grafted on the surface, without modifying the massive properties of the bulk. Plasma surface modification was performed in a capacitively-coupled rf (13.56 MHz) glass reactor fed with different precursors like N2, H2O, C2H4 to study the effect of plasma parameters on the chemical properties of the resulting material and its ability to improve the immobilization of polyelectrolyte MCPs. Cylindrical scaffolds were synthesized by freeze-drying technique and dehydrothermally crosslinked. Polyelectrolyte capsules were obtained by LbL method. Scaffolds were characterized by means of WCA and XPS. Fluorescence microscopy was used to verify MCPs immobilization. After treatments, scaffolds became hydrophilic and able to absorb water. The success of grafting, on the external surface and within the scaffold core, was clearly revealed. The obtained results demonstrate that plasma processing of cross-linked collagen allows to enhance MCPs immobilization and that, by changing the typology of functional groups on the plasma treated surfaces, a different attitude to immobilize negatively or positively charged MCPs is observed.

Wound closure represents a primary goal in the treatment of very deep and/or large wounds, for which the mortality rate is particularly high. However, the spontaneous healing of adult skin eventually results in the formation of epithelialized scar and scar contracture (repair), which might distort the tissues and cause lifelong deformities and disabilities. This clinical evidence suggests that wound closure attained by means of skin regeneration, instead of repair, should be the true goal of burn wound management. The traditional concept of temporary wound dressings, able to stimulate skin healing by repair, is thus being increasingly replaced by the idea of temporary scaffolds, or regenerative templates, able to promote healing by regeneration. As wound dressings, polymeric hydrogels provide an ideal moisture environment for healing while protecting the wound, with the additional advantage of being comfortable to the patient, due to their cooling effect and non-adhesiveness to the wound tissue. More importantly, recent advances in regenerative medicine demonstrate that bioactive hydrogels can be properly designed to induce at least partial skin regeneration in vivo. The aim of this review is to provide a concise insight on the key properties of hydrogels for skin healing and regeneration, particularly highlighting the emerging role of hydrogels as next generation skin substitutes for the treatment of full-thickness burns.

The present work deals with the development of a biodegradable superabsorbent hydrogel, based on cellulose derivatives, for the optimization of water resources in agriculture, horticulture and, more in general, for instilling a wiser and savvier approach to water consumption. The sorption capability of the proposed hydrogel was firstly assessed, with specific regard to two variables that might play a key role in the soil environment, that is, ionic strength and pH. Moreover, a preliminary evaluation of the hydrogel potential as water reservoir in agriculture was performed by using the hydrogel in experimental greenhouses, for the cultivation of tomatoes. The soil-water retention curve, in the presence of different hydrogel amounts, was also analysed. The preliminary results showed that the material allowed an efficient storage and sustained release of water to the soil and the plant roots. Although further investigations should be performed to completely characterize the interaction between the hydrogel and the soil, such findings suggest that the envisaged use of the hydrogel on a large scale might have a revolutionary impact on the optimization of water resources management in agriculture.

In this work, a mixture of a sodium salt of carboxymethylcellulose (CMCNa) and polyethylene glycol diacrylate (PEGDA700) was used for the prepara- tion of a microporous structure by using the combination of two different procedures. First, physical foaming was induced using Pluronic as a blowing agent, followed by a chemical stabilization. This second step was carried out by means of an azobis(2-methylpropionamidine)dihydrochloride as the thermoinitiator (TI). This reaction was activated by heating the sample homo- geneously using a microwave generator. Finally, the influence of different CMCNa and PEGDA700 ratios on the final properties of the foams was inves- tigated. The viscosity, water absorption capacity, elastic modulus and porous structure were evaluated for each sample. In addition, preliminary biological characterization was carried out with the aim to prove the biocompatibility of the resulting material. The foam, including 20% of PEGDA700 in the mixture, demonstrated higher viscosity and stability before thermo-polymerization. In addition, increased water absorption capacity, mechanical resistance and a more uniform microporous structure were obtained for this sample. In particu- lar, foam with 3% of CMCNa shows a hierarchical structure with open pores of different sizes. This morphology increased the properties of the foams. The full set of samples demonstrated an excellent biocompatibility profile with a good cell proliferation rate of more than 7 days.

In the present work Collagen/Hydroxyapatite microsphere (Col/mHA) scaffold with a multiscale porosity was prepared. Col/mHA composite scaffold was prepared by freezedrying/ dehydrothermal crosslinking method. The HA microspheres (mHA) were obtained by spray drying of nano hydroxyapatite slurry prepared by precipitation technique. XRD analysis revealed that the microspheres were composed only of pure HA phase and EDS analysis revealed that Ca/P ratio was 1.69. The obtained microsphere had an average diameter 6 microns, specific surface area of 40 m2/g by BET analysis and BJH analysis shows meso porous structure having an average pore diameter 16nm. SEM analysis shows that the obtained Col/mHA scaffold had a macro porosity ranging from micron to 200 microns with meso porous mHA embedded in the collagen matrix.

The aim of this project was to study the proliferation and differentiation of human Mesenchymal Stem Cells (hMSCs) onto a cellulose-based hydrogel for bone tissue engineering. Methods: Modified-cellulose hydrogel was prepared via double esterification crosslinking using citric acid. The response of hMSCs in terms of cell proliferation and differentiation into osteoblastic phenotype was evaluated by using Alamar blue™ assay and alkaline phosphatase (ALP) activity. Results: The results showed that CMCNa and CMCNa_CA have no negative effect on hMSC, adhesion and proliferation. Moreover, the increase of the ALP expression for CMCNa_CA confirms the ability of the hydrogels to support the osteoblastic differentiation. Conclusions: The cellulose-based hydrogels have a potential application as filler in bone tissue regeneration.

Rapid prototyping techniques have been investigated for the production of biomedical devices that perfectly fit the patient's tissue defect (e.g. for bone and dental applications) and/or reproduce the microstructure of the tissue or organ of interest. The possibility to create patient-specific devices has been recently exploited for the creation of tissue engineer-ing scaffolds, i.e. porous, resorbable matrices, which stimulate cell functions and induce tissue regenera-tion by providing cells with appropriate physical, mechanical and biochemical cues. Poly(ethylene glycol) (PEG)-based hydrogels, although intrinsically non-biodegradable and non-bioactive, show great promise as tissue engineering scaffolds, due to their ability to be covalently linked to bioactive and/or degradable moieties, that elicit specific cell responses, and to their fast and biocompatible formation under ultra-violet (UV) exposure. In this work, poly(ethylene glycol)-based hydrogels, containing bioactive moieties, were photopolymerized and characterized in terms of mechanical, swelling and degradation properties. The production of hydrogels possessing a complex shape was finally investigated by means of stereolithography, a rapid prototyping technique which is able to build a three-dimensional object, starting from the CAD model, by guiding an ultravio-let laser beam on the surface of a photosensitive solution. The results demonstrated that the developed hydrogel formulations allow the creation of biomimetic constructs with complex shapes, which might be useful as platforms for tissue engineering or as tissue mimicking phantoms.

Biomimetic scaffolds with a structural and chemical composition similar to native bone tissue may be promising for bone tissue regeneration. In the present work hydroxyapatite mesoporous microspheres (mHA) were incorporated into collagen scaffolds containing an ordered interconnected macroporosity. The mHA were obtained by spray drying of a nano hydroxyapatite slurry prepared by the precipitation technique. X-ray diffraction (XRD) analysis revealed that the microspheres were composed only of hydroxyapatite (HA) phase, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the Ca/P ratio to be 1.69 which is near the value for pure HA. The obtained microspheres had an average diameter of 6 μm, a specific surface area of 40 m(2)/g as measured by Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis showed a mesoporous structure with an average pore diameter of 16 nm. Collagen/HA-microsphere (Col/mHA) composite scaffolds were prepared by freeze-drying followed by dehydrothermal crosslinking. SEM observations of Col/mHA scaffolds revealed HA microspheres embedded within a porous collagen matrix with a pore size ranging from a few microns up to 200 μm, which was also confirmed by histological staining of sections of paraffin embedded scaffolds. The compressive modulus of the composite scaffold at low and high strain values was 1.7 and 2.8 times, respectively, that of pure collagen scaffolds. Cell proliferation measured by the MTT assay showed more than a 3-fold increase in cell number within the scaffolds after 15 days of culture for both pure collagen scaffolds and Col/mHA composite scaffolds. Attractive properties of this composite scaffold include the potential to load the microspheres for drug delivery and the controllability of the pore structure at various length scales.

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.

Authors aimed to provide a magnetic responsiveness to bone-mimicking nano-hydroxyapatite (n-HA). For this purpose, dextran-grafted iron oxide nanoarchitectures (DM) were synthesized by a green friendly and scalable alkaline co-precipitation method at room temperature and used to functionalize n-HA crystals. Different amounts of DM hybrid structures were added into the nanocomposites (DM/n-HA 1:1, 2:1 and 3:1weight ratio) which were investigated through extensive physicochemical (XRD, ICP, TGA and Zetapotential), microstructural (TEM and DLS), magnetic (VSM) and biological analyses (MTT proliferation assay). X-ray diffraction patterns have confirmed the n-HA formation in the presence of DM as a co-reagent. Furthermore, the addition of DM during the synthesis does not affect the primary crystallite domains of DM/n-HA nanocomposites. DM/n-HAs have shown a rising of the magnetic moment values by increasing DM content up to 2:1 ratio. However, the magnetic moment value recorded in the DM/n-HA 3:1 do not further increases showing a saturation behavior. The cytocompatibility of the DM/n-HA was evaluated with respect to the MG63 osteoblast-like cell line. Proliferation assays revealed that viability, carried out in the absence of external magnetic field, was not affected by the amount of DM employed. Interestingly, assays also suggested that the DM/n-HA nanocomposites exhibit a possible shielding effect with respect to the antiproliferative activity induced by the DM particles alone.

Cell-cell interactions promote juxtacrine signals in specific subcellular domains, which are difficult to capture in the complexity of the nervous system. For example, contact between axons and Schwann cells triggers signals required for radial sorting and myelination. Failure in this interaction causes dysmyelination and axonal degeneration. Despite its importance, few molecules at the axo-glial surface are known. To identify novel molecules in axo-glial interactions, we modified the 'pseudopodia' sub-fractionation system and isolated the projections that glia extend when they receive juxtacrine signals from axons. By proteomics we identified the signalling networks present at the glial-leading edge, and novel proteins, including members of the Prohibitin family. Glial-specific deletion of Prohibitin-2 in mice impairs axo-glial interactions and myelination. We thus validate a novel method to model morphogenesis and juxtacrine signalling, provide insights into the molecular organization of the axo-glial contact, and identify a novel class of molecules in myelination.

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.

In this study we investigated the impact of three different sterilization methods, dry heat (DHS), ethylene oxide (EtO) and electron beam radiation (β), on the properties of cylindrical collagen scaffolds with longitudinally oriented pore channels, specifically designed for peripheral nerve regeneration. Scanning electron microscopy, mechanical testing, quantification of primary amines, differential scanning calorimetry and enzymatic degradation were performed to analyze possible structural and chemical changes induced by the sterilization. Moreover, in vitro proliferation and infiltration of the rat Schwann cell line RSC96 within the scaffolds was evaluated, up to 10 days of culture. No major differences in morphology and compressive stiffness were observed among scaffolds sterilized by the different methods, as all samples showed approximately the same structure and stiffness as the unsterilized control. Proliferation, infiltration, distribution and morphology of RSC96 cells within the scaffolds were also comparable throughout the duration of the cell culture study, regardless of the sterilization treatment. However, we found a slight increase of chemical crosslinking upon sterilization (EtO < DHS < β), together with an enhanced resistance to denaturation of the EtO treated scaffolds and a significantly accelerated enzymatic degradation of the β sterilized scaffolds. The results demonstrated that β irradiation impaired the scaffold properties to a greater extent, whereas EtO exposure appeared as the most suitable method for the sterilization of the proposed scaffolds.

Collagen, the major component of the extracellular matrix, key factor of tissue architecture, provides tensile strength, cell-matrix and matrix-matrix interactions. 2-D and 3-D collagen constructs are widely used as tissue scaffolds in a variety of biomedical applications. Here we synthetized scaffolds structured as thin films (30-50 μm in thickness) and we characterized them from a structural and functional point of view. Type I collagen isolated from bovine tendon (Sigma Aldrich) was suspended at 0.5% w/v in dilute hydrochloric acid (pH=3-3.2) by mixing at 15,000 rpm in an overhead blender, under proper refrigeration. After degassing via centrifugation, the slurry was cast in polystyrene molds and dried for at least 48 hours at room temperature, to obtain dry collagen films. In order to modulate their mechanical properties and degradation rate, the samples were subjected to two different crosslinking treatments, either dehydrothermal crosslinking (DHT) only, at 121°C for 24 hours, or DHT treatment combined with chemical crosslinking by means of a water soluble carbodiimide (DHT/EDC). First, atomic force microscopy measurements of the films showed differences in structure reticulation. As expected, the DHT/EDC scaffold surface presented a more intricate fibrillar assembly, and a lower swelling degree after the first 24 hours (about 30% less). Once integrated into appositely fabricated polymeric devices, DHT and DHT/EDC scaffolds were tested in cellular oxygen consumption and proliferation assays. Fibroblasts, seeded at the same densities on both DHT and DHT/EDC substrates, displayed different oxygen consumption rate (OCR) within 48 hours, reflecting dissimilarities in terms of structural organization and oxygen diffusion efficiency. The obtained results could represent a useful approach to indicate some culture parameters, such as cell-seeding optimal values for the feasibility of tissue models, depending on scaffold structure design.

Le lesioni del midollo spinale nell’uomo sono molto eterogenee. L’incapacità di rigenerazione del midollo lesionato è attribuita all’instaurarsi di un ambiente inibitorio e alla formazione di una cicatrice gliale che funge da barriera chimica e meccanica alla rigenerazione assonale. L’impianto di scaffold microporosi rappresenta una valida strategia per guidare la rigenerazione, nel tentativo di ripristinare i collegamenti con i target di innervazione e promuovere il recupero funzionale. Porosità, distribuzione delle dimensioni dei pori, area superficiale specifica, interconnettività ed orientazione dei pori sono parametri cruciali che influenzano la bioattività dello scaffold. Lo scopo del presente lavoro è quello di modulare e caratterizzare la struttura microporosa di scaffold cilindrici in collagene, con porosità orientata in direzione longitudinale o assiale, destinati ad uno studio sulla rigenerazione del midollo spinale. Gli scaffold (3mm diametro, 3 cm lunghezza) sono stati realizzati mediante freezing unidirezionale di sospensioni di collagene di tipo I da derma bovino (a diverse concentrazioni), liofilizzazione e reticolazione termica e chimica. La porosità degli scaffold è stata quindi analizzata qualitativamente e quantitativamente mediante microscopia elettronica a scansione e ottica, al fine di determinare morfologia, omogeneità, diametro medio e grado di orientazione dei pori. L’analisi delle sezioni trasversali e longitudinali degli scaffold ha mostrato rispettivamente una distribuzione pressoché omogenea e una buona orientazione uniassiale dei pori per tutte le tipologie di campioni analizzate, evidenziando una leggera diminuzione della dimensione media all’aumentare della concentrazione di collagene utilizzata in fase di sintesi. Tuttavia, si è anche osservato un gradiente crescente del diametro medio dei pori lungo l’asse longitudinale degli scaffold, legato al gradiente di temperatura che si instaura durante il processo di freezing uniassiale. Inoltre, i trattamenti di reticolazione investigati sembrano non influenzare significativamente la microstruttura. Studi futuri saranno rivolti a comprendere l’effetto della microstruttura sul comportamento di cellule neuronali, immortalizzate e primarie, in vitro.

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.

In this work, we synthesized porous nanohydroxyapatite/collagen composite scaffold (nHA-COL), which resemble extracellular matrices in bone and cartilage tissues. Nano hydroxyapatite (nHA) was successfully nucleated in to the collagen matrix using hen eggshell as calcium biogenic source. Porosity was evaluated by apparent and theoretical density measurement. Porosity of all scaffolds was in the range of 95–98%. XRD and TEM analyses show the purity and size of nucleated HA around 10 nm and selected area electron diffraction (SAED) analysis reveals the polycrystalline nature of nucleated HA. SEM analysis reveals (i) all the scaffolds have interconnected pores with an average pore diameter of 130 micron and (ii) aggregates of hydroxyapatite were strongly embedded in the collagen matrix for both composite scaffolds compared with pure collagen scaffold. EDS analysis shows the Ca/P stoichiometric ratio around 1.67 and FTIR reveals the chemical interaction between the collagen molecule and HA particles. The testing of mechanical properties evidenced that incorporation of HA resulted in up to a two-fold increase in compressive modulus with high reinforcement level (∼ 7 kPa for 50HA–50COL) compared to pure collagen scaffold.

The aim of this work is to develop a novel approach to control the growth of food-borne and food-spoilage microorganisms while reducing the use of synthetic preservatives. Bioactive food-preserving systems are based on the use of a natural antimicrobial agent loaded in a carrier material, which is able to trigger its release once necessary and to control the rate of release, thereby exerting either lethal or inhibitory effects against food pathogens or spoilage microorganisms. In this study the Schiff base of chitosan was synthesized by the reaction with cinnamaldehyde at different concentrations (0,1%, 0,25%, 0,5% w/w of dry polymer). Cinnamaldehyde is an aromatic α,β-unsaturated aldehyde, and the major component in essential oils from some cinnamon species. It has been shown to exert antimicrobial activity against a wide range of microorganisms including bacteria, yeasts, and mould. The formation of the Schiff base is reversible under suitable conditions, and this might allow the release of the active cinnamaldehyde from chitosan, used as the carrier. The reaction kinetics was investigated by means of rheological analyses, while Fourier transform infrared spectroscopy (FTIR) was used to assess the efficacy of the functionalization. The results from FT-IR spectra highlighted the presence of the absorption peak of the Schiff base, which confirmed the reactivity of the nitrogen from amino group of chitosan and carbonyl carbon of the aldehyde to form imine. Moreover, the reaction rate was found to increase as higher percentages of cinnamaldehyde were used. Cinnamaldehyde-functionalized chitosan films were then prepared and tested for contact angle and antifungal properties in vitro. The envisaged application of the films for food packaging was also tested, by placing the films in direct contact with slices of bread. It was demonstrated that the cinnamaldehyde-functionalized chitosan films increased the shelf life of the product.

Porosity is a key parameter in the design of tissue engineering scaffolds, as bioactivity can be controlled and tailored to the synthesis of the target tissue by finely tuning the porous structure of the scaffolding biomaterial. This chapter discusses the effect of structural parameters, such as pore volume fraction, pore size and distribution, pore shape, pore interconnectivity and pore orientation, on the performance of sponge-like scaffolds, with a special focus on those directed to nerve regeneration.

This study evaluated a tendon substitute model. Tenocytes were isolated from pig Achilles tendon, seeded onto scaffolds (Opocrin 2%, Typeone 3% and Symatese 2%) and studied by histology, immunofluorescence for collagen type 1 and 3 and biochemical analysis to assess cellularity. The permeability of these compounds was evaluated in the presence or absence of fibrin glue. Opocrin 2% was the best choice for cellular distribution within the scaffolds, which were then cultured for T0, T4, T7 and T10 days. Fibrin glue has been strongly supportive for the survival of cells with a significant increase in DNA content at T10 (P<0.05). Moreover, the synthetic activity of fibrin-free scaffolds was always negative. Lastly, a progressive increase in collagen 1 and 3 with fibrin-glue was observed. However, static culture is not sufficient to support long-term cellular activities and at T10 there is still a lack of organized matrix similar to the native tissue.

Objectives: The aim of the present work is the in vitro optimization of the chondral phase of an osteochondral scaffold and the analysis of the effect of the fibrin glue as embedding scaffold for the seeded chondrocytes. Methods: Fresh chondrocytes were seeded onto the scaffold by embedding them in fibrin glue or in medium as control. In the second part of the study, chondrocytes were isolated and expanded in the presence of specific growth factors; they were resuspended in fibrinogen and seeded onto the scaffold that was cultured in vitro for 1, 3 and 5 weeks in a chondrogenic medium. Results: histological and immunohistochemical data demonstrated that the presence of fibrin glue ameliorated cell distribution and survival into the chondral composite. Data from the second part of the study showed that chondrocytes’ phenotype was rescued after 3 weeks of in vitro culture and maintained for the following weeks; the biomechanical properties improved during time but they started to decrease between week 3 and 5. Conclusion: The in vitro data demonstrated that chondrocytes can grow and promote the formation of a mature cartilaginous tissue when seeded on the chondral scaffold proposed in this study; their survival and activity are ameliorated by the presence of fibrin gel as embedding scaffold and by maintaining the vitro culture for 3 weeks in the presence of specific growth factors.

Wollastonite/hydroxyapatite composite scaffolds are proposed as bone graft. An investigation on scaffold with varying reinforcing wollastonite content fabricated by polymeric sponge replica is reported. The composition, sintering behavior, morphology, porosity and mechanical strength were characterized. All the scaffolds had a highly porous well-interconnected structure. A significant increase in mechanical strength is achieved by adding a 50% wollastonite phase. The most mechanically resistant (50/50) wollastonite/hydroxyapatite scaffolds were soaked in both simulated body fluid (SBF) and Tris–HCl solution in order to assess bioactivity and biodegradability. A carbo-hydroxyapatite layer formed on their surfaces when immersed in SBF. The biodegradability tests reveals that the composite scaffold shows a higher degradation rate compared to pure hydroxyapatite used as comparison. These results demonstrate that the incorporation of a 50% of wollastonite phase in hydroxyapatite matrix is effective in improving the strength and the bioactive and biodegradable properties of the porous scaffolds.

A synthetic composite material for tissue repair is disclosed which includes a first layer having an organic material and having side walls and external surface; and a second porous layer comprising an inorganic material and having side walls; wherein the first layer is in direct contact with the second layer and wherein the side walls of the first layer and the side walls of the second layer are coated with a third layer of the organic material

The present invention relates to methods of managing weight, and treating overweight or obesity and treating or preventing diabetes in a subject in need thereof. In one embodiment, the method comprises the steps of (a) orally administering to the subject from about 0.7 g to about 4 g of crosslinked carboxymethylcellulose; and (b) orally administering to the subject at least about 100 mL of water per gram of crosslinked carboxymethylcellulose. Steps (a) and (b) are conducted prior to or with at least one meal per day.

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.

A device (1) for regenerating biological tissues, particularly for regenerating tissues of the peripheral nervous system, the respective manufacturing method (100) and the instrument (11) used in the method, the regeneration device (1) comprising a hollow tubular structure (2) based on biocompatible material and having a structural porosity in which the pores are oriented substantially radially with respect to its longitudinal axis (3) so as to minimize the formation of scar tissue around the damaged site and allow the growth of the biological tissue inside the pores and inside the duct (4) defined by the hollow tubular structure (2) and facilitate the transport of nutrients.

A method (100) for manufacturing a device (1) for regenerating biological tissues, particularly for regenerating tissues of the central nervous system, and a device (1) that can be manufactured with said method (100), the device (1) comprising an outer sheath (2) based on collagen which is substantially tubular and can be interposed between the endings of a biological tissue to be regenerated, and at least one supporting element (3) based on collagen, which is accommodated inside the outer sheath (2).

The present invention provides a method of producing a polymer hydrogel comprising the steps of: (1) preparing an aqueous solution of a water soluble polysaccharide derivative and a polycarboxylic acid; (2) optionally agitating the solution, for example, by stirring; (3) isolating a polysaccharide derivative/polycarboxylic acid composite from the solution; and (4) heating the polysaccharide derivative/polycarboxylic acid composite at a temperature of at least about 80° C., thereby cross-linking the polysaccharide with the polycarboxylic acid. The invention also provides polymer hydrogels produced by the methods of the invention.

The present invention provides methods, compositions and modified foods and foodstuffs useful for weight management and glycemic control.

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.

The invention relates to a method for the preparation of a superabsorbent polymer hydrogel, comprising crosslinking a precursor comprising a carboxymethylcellulose salt optionally in combination with hydroxyethylcellulose, using citric acid as the crosslinking. agent and in the presence of a molecular spacer, subsequently washing the gel in a polar organic solvent and finally drying the gel by phase inversion in a non-solvent for cellulose. The invention further concerns the superabsorbent hydrogel obtainable by the method of the invention and the use thereof in a number of different applications.

A method for producing bone substitutes and/or fillers made to measure and made of bioactive and biomimetic materials, and to the bone substitute and/or filler obtainable with such method, comprising the steps of: - receiving clinical images of the bone defect from a clinical unit, - processing the received image in order to obtain a virtual prototype of a female mold part and male mold part of the bone defect, - converting the virtual prototype into a format which is compatible with a rapid prototyping machine, - selecting a material of which the female mold part and the male mold part are to be made, in order to provide female mold parts and male mold parts made of different materials depending on the type of production method used to obtain the bone substitute, - providing the female mold part and the male mold part by way of the rapid prototyping machine, - selecting a material of which the bone filler or substitute is to be made, - providing the bone filler or substitute. A method for producing bone substitutes and/or fillers made to measure and made of bioactive and biomimetic materials, and to the bone substitute and/or filler obtainable with such method, comprising the steps of: - receiving clinical images of the bone defect from a clinical unit, - processing the received image in order to obtain a virtual prototype of a female mold part and male mold part of the bone defect, - converting the virtual prototype into a format which is compatible with a rapid prototyping machine, - selecting a material of which the female mold part and the male mold part are to be made, in order to provide female mold parts and male mold parts made of different materials depending on the type of production method used to obtain the bone substitute, - providing the female mold part and the male mold part by way of the rapid prototyping machine, - selecting a material of which the bone filler or substitute is to be made, - providing the bone filler or substitute.