Carboxymethyl cellulose-based hydrogel film combined with berberine as an innovative tool for chronic wound management.

Polysaccharide-based hydrogels are achieving remarkable performances in chronic wounds treatment. In this work, a carboxymethyl cellulose-based hydrogel film was developed to support skin repair. The hydrogel was loaded with berberine, a polyphenolic molecule endowing antioxidant and cytoprotective features. The film was physico-chemically characterized and in vitro tested on keratinocytes and fibroblasts subjected to oxidative stress. The biocomposite showed high thermal stability (onset decomposition temperature 245 °C) and significant fluid uptake performances, both in free conditions (up to 6510%) and under external pressure (up to 3400%). Moreover, it was able to control oxidative stress and inflammation markers involved in wound chronicity. Keratinocytes hyperproliferation, features that normally hamper injury restoration, was reduced of 25%. Our results showed that the combination of berberine and hydrogel provides a synergic improvement of the material properties. The biocomposite represents a promising candidate for dermatological applications against oxidative stress at the chronic wound site, promoting the healing process.

Effect of red thyme oil (Thymus vulgaris L.) vapours on fungal decay, quality parameters and shelf-life of oranges during cold storage.

This work has been aimed at studying the effect of red thyme oil (RTO, Thymus vulgaris L.) on the shelf-life and Penicillium decay of oranges during cold storage. RTO vapours significantly reduced (P ≤ 0.05) the percentage of infected wounds, the external growth area and the production of spores in inoculated orange fruit stored for 12 days at 7 °C in a polypropylene film selected for its appropriate permeability. Among the RTO compounds, p-cymene and thymol were the most abundant in packed boxes at the end of cold storage. The RTO vapours did not affect the main quality parameters of the oranges, or the taste and odour of the juice. The results have shown that an active packaging, using RTO vapours, could be employed, by the citrus industry, to extend the shelf-life of oranges for fresh market use and juice processing.

Protection of dopamine towards autoxidation reaction by encapsulation into non-coated- or chitosan- or thiolated chitosan-coated-liposomes.

The aim of this work is to evaluate the potential of non-coated-, chitosan-(CS)- or chitosan-glutathione conjugate- (CS-GSH)-coated liposomes to protect the neurotransmitter Dopamine (DA) from the autoxidation reaction in neutral/alkaline conditions. This may be of interest in the development of nanotechnology-based approaches to improve Parkinson's disease treatment because decreased ROS production and reduced DA associated neurotoxicity are expected. For the mentioned purposes, DA-loaded vesicles were prepared by the Dried Reconstituted Vesicles (DRV) method, and were subsequently coated using solutions of polycations. As for the mean diameters of liposomes so prepared, the CS-GSH coated liposomes showed a significant decrease in size compared to the corresponding non-coated and CS-coated vesicles. The surface charge of DA-loaded non-coated liposomes was -10.8 mV, whereas the CS or CS-GSH coated vesicles showed a slightly positive ζ-potential. The capability of the herein studied vesicles to prevent DA autoxidation was evaluated by visual inspection, monitoring DA/lipid ratio as such and under stressed conditions. The results suggest that liposome formulations partially protect the neurotransmitter from the autoxidation reaction. In particular, the CS-GSH coated liposomes were more stable than the corresponding CS-coated and non-coated ones against the oxidative damage and were found to deliver the neurotransmitter in a sustained manner. Probably, this is due to the localization of the neurotransmitter in the core of the vesicles as indicated by XPS which confirmed the absence of the neurotransmitter on the surface of these vesicles.

Data on glycerol/tartaric acid-based copolymer containing ciprofloxacin for wound healing applications.

This data article is related to our recently published research paper "Exploiting a new glycerol-based copolymer as a route to wound healing: synthesis, characterization and biocompatibility assessment", De Giglio et al. (Colloids and Surfaces B: Biointerfaces 136 (2015) 600-611) [1]. The latter described a new copolymer derived from glycerol and tartaric acid (PGT). Herein, an investigation about the PGT-ciprofloxacin (CIP) interactions by means of Fourier Transform Infrared Spectroscopy (FT-IR) acquired in Attenuated Total Reflectance (ATR) mode and Differential Scanning Calorimetry (DSC) was reported. Moreover, CIP release experiments on CIP-PGT patches were performed by High Performance Liquid Chromatography (HPLC) at different pH values.

Data in support of Gallium (Ga(3+)) antibacterial activities to counteract E. coli and S. epidermidis biofilm formation onto pro-osteointegrative titanium surfaces.

This paper contains original data supporting the antibacterial activities of Gallium (Ga(3+))-doped pro-osteointegrative titanium alloys, obtained via Anodic Spark Deposition (ASD), as described in "The effect of silver or gallium doped titanium against the multidrug resistant Acinetobacter baumannii" (Cochis et al. 2016) [1]. In this article we included an indirect cytocompatibility evaluation towards Saos2 human osteoblasts and extended the microbial evaluation of the Ga(3+) enriched titanium surfaces against the biofilm former Escherichia coli and Staphylococcus epidermidis strains. Cell viability was assayed by the Alamar Blue test, while bacterial viability was evaluated by the metabolic colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Finally biofilm morphology was analyzed by Scanning Electron Microscopy (SEM). Data regarding Ga(3+) activity were compared to Silver.

The effect of silver or gallium doped titanium against the multidrug resistant Acinetobacter baumannii.

Implant-related infection of biomaterials is one of the main causes of arthroplasty and osteosynthesis failure. Bacteria, such as the rapidly-emerging Multi Drug Resistant (MDR) pathogen Acinetobacter Baumannii, initiate the infection by adhering to biomaterials and forming a biofilm. Since the implant surface plays a crucial role in early bacterial adhesion phases, titanium was electrochemically modified by an Anodic Spark Deposition (ASD) treatment, developed previously and thought to provide osseo-integrative properties. In this study, the treatment was modified to insert gallium or silver onto the titanium surface, to provide antibacterial properties. The material was characterized morphologically, chemically, and mechanically; biological properties were investigated by direct cytocompatibility assay, Alkaline Phosphatase (ALP) activity, Scanning Electron Microscopy (SEM), and Immunofluorescent (IF) analysis; antibacterial activity was determined by counting Colony Forming Units, and viability assay. The various ASD-treated surfaces showed similar morphology, micrometric pore size, and uniform pore distribution. Of the treatments studied, gallium-doped specimens showed the best ALP synthesis and antibacterial properties. This study demonstrates the possibility of successfully doping the surface of titanium with gallium or silver, using the ASD technique; this approach can provide antibacterial properties and maintain high osseo-integrative potential.

Exploiting a new glycerol-based copolymer as a route to wound healing: Synthesis, characterization and biocompatibility assessment.

The use of biocompatible materials based on naturally derived monomers plays a key role in pharmaceutical and cosmetic industries. In this paper we describe the synthesis of a new low molecular weight copolymer, based on glycerol and l-tartaric acid, useful to develop biocompatible dermal patches with drug delivery properties. The copolymer's chemical composition was assessed by FT-IR (Fourier transform infrared spectroscopy), (1)H NMR ((1)H Nuclear Magnetic Resonance) and XPS (X-ray photoelectron spectroscopy), while its molecular weight distribution was estimated by SEC (size exclusion chromatography). Copolymer thermal properties were studied by TGA (thermogravimetric analysis). Biological evaluations by MTT assay and SEM (scanning electron microscopy) observations performed with murine fibroblasts and human keratinocytes (HaCaT) revealed a good compatibility of the proposed copolymer. Ciprofloxacin was selected as model drug and its release was evaluated by HPLC (high performance liquid chromatography), showing that the new copolymer supplied promising results as drug delivery system for wound healing applications. Furthermore, investigations on Skin-Mesenchymal stem cells (S-MSCs) behaviour and gene expression showed that the copolymer and its combination with ciprofloxacin did not affect their stemness. In this regard, the fabrication of dermal patches with new, low cost materials for local treatment of skin infections represents an attractive strategy in order to bypass the worrying side effects of systemic antibiotic therapy. Overall, the performed physico-chemical characterization, drug release test and biological evaluations showed that this new copolymer could be a promising tool for the in situ delivery of bioactive molecules during skin lesions treatment.

An innovative, easily fabricated, silver nanoparticle-based titanium implant coating: development and analytical characterization.

Microbial colonization and biofilm formation on implanted devices represent an important complication in orthopaedic and dental surgery and may result in implant failure. Controlled release of antibacterial agents directly at the implant site may represent an effective approach to treat these chronic complications. Resistance to conventional antibiotics by pathogenic bacteria has emerged in recent years as a major problem of public health. In order to overcome this problem, non-conventional antimicrobial agents have been under investigation. In this study, polyacrylate-based hydrogel thin coatings have been electrosynthesised on titanium substrates starting from poly(ethylene glycol diacrylate)-co-acrylic acid. Silver nanoparticles (AgNPs) with a narrow size distribution have been synthesized using a "green" procedure and immobilized on Ti implant surfaces exploiting hydrogel coatings' swelling capabilities. The coatings have been characterized by XPS and SEM/EDX, while their silver release performances have been monitored by ICP-MS. The antibacterial activity of these AgNP-modified hydrogel coatings was tested evaluating in vitro inhibition growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, among the most common pathogens in orthopaedic infections. Moreover, a preliminary investigation of the biocompatibility of silver-loaded coatings versus MG63 human osteoblast-like cells has been performed. An important point of strength of this paper, in fact, is the concern about the effect of silver species on the surrounding cell system in implanted medical devices. Silver ion release has been properly tuned in order to assure antibacterial activity while preserving osteoblasts' response at the implant interface.

Antibiotic-modified hydrogel coatings on titanium dental implants.

Implant-associated infections represent an occasional but serious problem in dental and/or orthopaedic surgery. A possible solution to prevent the initial bacterial adhesion may be the coating of the implant surface with a thin layer of antibiotic-loaded biocompatible polymer. Hydrogels are one of the promising and versatile materials as antibiotic controlled release systems. In this work, antibiotic-modified poly(ethylene-glycol diacrylate) hydrogel coatings on titanium substrates were prepared by electrochemical polymerization and tested against methicillin resistant Staphylococcus aureus (ATCC 33591). Two different methods to load vancomycin and ceftriaxone were used. We show that the proposed titanium coatings displayed an interesting antibacterial activity, however, further studies on their effective cytotoxicity will furnish evidence of their real clinical efficacy.

Ciprofloxacin-modified electrosynthesized hydrogel coatings to prevent titanium-implant-associated infections.

New promising and versatile materials for the development of in situ sustained release systems consisting of thin films of either poly(2-hydroxyethyl methacrylate) or a copolymer based on poly(ethylene-glycol diacrylate) and acrylic acid were investigated. These polymers were electrosynthesized directly on titanium substrates and loaded with ciprofloxacin (CIP) either during or after the synthesis step. X-ray photoelectron spectroscopy was used to check the CIP entrapment efficiency as well as its surface availability in the hydrogel films, while high-performance liquid chromatography was employed to assess the release property of the films and to quantify the amount of CIP released by the coatings. These systems were then tested to evaluate the in vitro inhibition of methicillin-resistant Staphylococcus aureus (MRSA) growth. Moreover, a model equation is proposed which can easily correlate the diameter of the inhibition haloes with the amount of antibiotic released. Finally, MG63 human osteoblast-like cells were employed to assess the biocompatibility of CIP-modified hydrogel coatings.

Electrosynthesis of hydrogel films on metal substrates for the development of coatings with tunable drug delivery performances.

Novel polyacrylates-based hydrogel thin films were prepared by electrochemical polymerization, a new method to obtain hydrogels directly onto metal substrates. 2-Hydroxy-ethyl-methacrylate (HEMA), a macromer poly (ethylene-glycol diacrylate) (PEGDA) and PEGDA copolymerized with acrylic acid (AA) were used to obtain hydrogels. The electrosynthesized coatings were characterized by X-ray photoelectron spectroscopy, to assess their surface chemical composition, and by water content determination measurements, to characterize the swelling behavior. In particular, quartz crystal microbalance with dissipation monitoring was used to evaluate the pH-dependency of the swelling for AA-containing hydrogels. Moreover, a model protein (bovine serum albumin) and a model drug (caffeine) were entrapped within the hydrogel coatings during electrosynthesis, to examine the release performances and mechanisms of the electrosynthesized hydrogels. It was observed that all the examined polymers showed significant release properties and, in particular, AA-containing hydrogel films confirmed a strong pH-dependence as expected. These coatings seem to be promising in orthopedic field for in situ drug delivery applications.

Analytical investigations of poly(acrylic acid) coatings electrodeposited on titanium-based implants: a versatile approach to biocompatibility enhancement.

A polyacrylic acid film was synthesized on titanium substrates from aqueous solutions via an electroreductive process for the first time. This work was done in order to develop a versatile coating for titanium-based orthopaedic implants that acts as both an effective bioactive surface and an effective anti-corrosion barrier. The chemical structure of the PAA coating was investigated by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was employed to evaluate the effect of annealing treatment on the morphology of the coatings in terms of their uniformity and porosity. Inductively coupled plasma mass spectrometry was used to measure ion concentrations in ion release tests performed on Ti-6Al-4V sheets modified with PAA coatings (annealed and unannealed). Results indicate that the annealing process produces coatings that possess considerable anti-corrosion performance. Moreover, the availability and the reactivity of the surface carboxylic groups were exploited in order to graft biological molecules onto the PAA-modified titanium implants. The feasibility of the grafting reaction was tested using a single aminoacid residue. A fluorinated aminoacid was selected, and the grafting reaction was monitored both by XPS, using fluorine as a marker element, and via quartz crystal microbalance (QCM) measurements. The success of the grafting reaction opens the door to the synthesis of a wide variety of PAA-based coatings that are functionalized with selected bioactive molecules and promote positive reactions with the biological system interfacing the implant while considerably reducing ion release into surrounding tissues.

Synthesis, analytical characterization and bioactivity of Ag and Cu nanoparticles embedded in poly-vinyl-methyl-ketone films.

The electrosynthesis of copper and silver core-shell nanoparticles (NPs) by the sacrificial anode technique, employing tetraoctylammonium (TOA) salts as base electrolyte for the first time, is described. These surfactants were selected because they combine high NP stabilizing power with useful disinfecting properties. The resulting colloids were mixed with a solution of an inert dispersing polymer and used to prepare nanostructured composite thin films. The morphologies and chemical compositions of the nanomaterials were characterized by Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The TEM reveals that the average core diameter of the metal NPs ranges between 1.7 and 6.3 nm, as a function of the nature of the metal and of the electrosynthesis conditions, and does not change significantly upon inclusion in the polymer matrix. An appreciable concentration of the metal is detected on the nanoparticle surface by XPS. High-resolution XP spectra indicate that both copper and silver are present at zero oxidation state in all of the materials (colloids and composite films). This demonstrates the high efficiency of the surfactant at controlling the morphology and the chemical composition of the nanodispersed metal in both the as-synthesized colloid and in the polymeric dispersion. The nanocoatings are shown to exert a marked inhibitory effect on the growth of eukaryote and prokaryote target microrganisms, and experimental evidence of a synergic disinfecting effect due to the surfactant and the nanodispersed metal is provided. On the basis of these stability and bioactivity results, it is clear that Cu-NPs and Ag-NPs are suitable for application in disinfecting or antifouling paint and coating formulations.

Electrosynthesis and analytical characterization of PMMA coatings on titanium substrates as barriers against ion release.

The performance of polyacrylic coatings as barrier films against corrosion of titanium-based orthopaedic implants was investigated. In particular, poly(methyl methacrylate) (PMMA) was electrosynthesized on titanium substrates by electro-reductive processes from aqueous monomer solutions. The obtained PMMA coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The effect of an annealing treatment on the morphology of coatings with respect to uniformity and porosity of films was assessed by scanning electron microscopy (SEM). An inductively coupled plasma-mass spectrometry (ICP-MS) technique was used for ion concentration measurements in ion release tests performed on TiAlV sheets modified with PMMA coatings (annealed and unannealed). Results indicated that the annealing process produces coatings with considerable anticorrosion performances.

Electropolymerization of pyrrole on titanium substrates for the future development of new biocompatible surfaces.

Titanium and its alloys are widely used in load-bearing implants as a result of their excellent mechanical properties and corrosion resistance. In order to improve their performances with respect to osseointegration, the use of bioactive coatings has been suggested. Polypyrrole (PPy) has been chosen as coating polymer because of its ability to be electrochemically grown directly onto metallic substrates, of any shape and dimension, leading to remarkably adherent overlayers. This polymer, in addition to protecting the metal implant against corrosion, could be surface modified with biologically active molecules able to stimulate positive interactions with bone tissue. In this work, PPy electrosynthesis on both titanium and Ti-Al-V substrates has been investigated. The chemical composition and the morphology of the polymeric films, deposited under different conditions, were evaluated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively.

Analytical characterization of collagen- and/or hydroxyapatite-modified polypyrrole films electrosynthesized on Ti-substrates for the development of new bioactive surfaces.

The design and development of new bioactive surfaces on titanium-based materials employed in orthopedic implants is described. The new biosurfaces consist of thin polypyrrole films, directly grown on implant materials and modified by the inclusion of hydroxyapatite and/or collagen during the polymer electrodeposition step. The experimental procedure has been optimized in terms of loading and distribution of the bioactive components. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) investigations have been performed in order to control the effectiveness of film modifications. In particular, XPS has been used to check the presence of biocompounds in the surface and sub-surface region of the polymer film, which is a critical requisite for a positive interface interaction between the biomaterial and the surrounding tissue.

A combined XPS-SEM/EDX investigation on explanted UHMW polyethylene acetabular cups: possible role of silicon traces in the wear debris.

An investigation was started aimed at a better understanding of the complex phenomena leading to chemical degradation and morphological deterioration of UHMW polyethylene cups in total hip prostheses. Analysis was performed on retrieved implants which needed revision due to inflammation and pain problems. Preliminary results obtained by parallel XPS and SEM/EDX experiments gave evidence, for the first time, that silicon traces are involved in the process of particle formation and segregation onto the surface of the cups. The extent of modification of the surface chemical composition of cups and the process of particle segregation seem to be correlated to both the implant time and to some particular features of patient (age, activity, style of life, etc.). Investigation on a large number of samples is in progress in order to test this hypothesis. The results obtained so far confirmed the potential of surface spectroscopies (XPS) in biomaterial investigations.

Synthesis, analytical characterization, and osteoblast adhesion properties on RGD-grafted polypyrrole coatings on titanium substrates.

The covalent attachment of an Arg-Gly-Asp (RGD) containing peptide to polypyrrole(PPy)-coated titanium substrates has been investigated in order to develop a bioactive material of potential use in orthopedic fields. Polypyrrole has been employed as the coating polymer because of its suitability to be electrochemically grown directly onto metallic substrates of different shapes, leading to remarkably adherent films. The synthetic peptide Cys-Gly-(Arg-Gly-Asp)-Ser-Pro-Lys, containing the cell-adhesive region of fibronectin (RGD), has been grafted to the polymer substrate via the cysteine residue using a procedure recently developed in the authors laboratory. The effectiveness of grafting was monitored by X-ray photoelectron spectroscopy (XPS), which assessed the presence of the peptide grafted onto the polymer surface exploiting the cysteine sulfur as target element. Neonatal rat calvarial osteoblasts were attached to RGD-modified PPy-coated Ti substrates at levels significantly greater than on unmodified PPy-coated Ti and glass coverslip substrates.

Development and analytical characterization of cysteine-grafted polypyrrole films electrosynthesized on Pt- and Ti-substrates as precursors of bioactive interfaces.

The grafting of cysteine to polypyrrole(PPY)-coated platinum and titanium substrates has been investigated with the aim of developing innovative bioactive materials of interest for bone implants. Polypyrrole has been chosen as the coating polymer because of its suitability to be electrochemically grown directly onto metallic substrates, of any shape and dimension, leading to remarkably adherent overlayers. The effectiveness of grafting was monitored by X-ray photoelectron spectroscopy (XPS) which showed the presence of aminoacid residues onto the polymer surface. Information obtained by an accurate curve fitting of significant regions in the spectra (C1s, N1s, and O1s signals) and by a cross-check of peak area ratios, before and after the grafting process, gave evidence that cysteine forms covalent bonds to pyrrole rings, preferentially in beta-positions, via the sulfydryl group, leaving both amino and carboxylic functionalities available for further chemistry. The surface density of cysteine residues was evaluated by microgravimetric measurements performed by the electrochemical quartz crystal microbalance and was found suitable for the exploitation of these modified surfaces as bioactive systems. Some preliminary results are reported on the adhesion of neonatal rat calvarial osteoblasts onto titanium substrates after coating by a PPY film modified by a polypeptide having cysteine as a terminal residue and containing the Arg-Gly-Asp aminoacid adhesive sequence.