The frontiers of antibacterial materials in the biomedical field are constantly evolving since infectious diseases are a continuous threat to human health. In this work, waste-wool-derived keratin ...electrospun nanofibers were blended with copper by an optimized impregnation procedure to fabricate antibacterial membranes with intrinsic biological activity, excellent degradability and good cytocompatibility. The keratin/copper complex electrospun nanofibers were multi-analytically characterized and the main differences in their physical-chemical features were related to the crosslinking effect caused by Cu
. Indeed, copper ions modified the thermal profiles, improving the thermal stability (evaluated by differential scanning calorimetry and thermogravimetry), and changed the infrared vibrational features (determined by infrared spectroscopy) and the chemical composition (studied by an X-ray energy-dispersive spectroscopy probe and optical emission spectrometry). The copper impregnation process also affected the morphology, leading to partial nanofiber swelling, as evidenced by scanning electron microscopy analyses. Then, the membranes were successfully tested as antibacterial materials against gram-negative bacteria,
. Regarding cytocompatibility, in vitro assays performed with L929 cells showed good levels of cell adhesion and proliferation (XTT assay), and no significant cytotoxic effect, in comparison to bare keratin nanofibers. Given these results, the material described in this work can be suitable for use as antibiotic-free fibers for skin wound dressing or membranes for guided tissue regeneration.
Bio sustainable hydrogels including tunable morphological and/or chemical cues currently offer a valid strategy of designing innovative systems to enhance healing/regeneration processes of damaged ...tissue areas. In this work, TEMPO-oxidized cellulose nanofibrils (T-CNFs) were embedded in alginate (Alg) and polyvinyl alcohol (PVA) solution to form a stable mineralized hydrogel. A calcium chloride reaction was optimized to trigger a crosslinking reaction of polymer chains and mutually promote in situ mineralization of calcium phosphates. FTIR, XRD, SEM/EDAX, and TEM were assessed to investigate the morphological, chemical, and physical properties of different mineralized hybrid hydrogels, confirming differences in the deposited crystalline nanostructures, i.e., dicalcium phosphate dehydrate (DCPDH) and hydroxyapatite, respectively, as a function of applied pH conditions (i.e., pH 4 or 8). Moreover, in vitro tests, in the presence of HFB-4 and HSF skin cells, confirmed a low cytotoxicity of the mineralized hybrid hydrogels, and also highlighted a significant increase in cell viability via MTT tests, preferentially, for the low concentration, crosslinked Alg/PVA/calcium phosphate hybrid materials (<1 mg/mL) in the presence of hydroxyapatite. These preliminary results suggest a promising use of mineralized hybrid hydrogels based on Alg/PVA/T-CNFs for bone and wound healing applications.
Electrospinning is the leading technology to fabricate fibrous scaffolds that mimic the architecture of the extracellular matrix of natural tissues. In order to improve the biological response, a ...consolidated trend involves the blending of synthetic polymers with natural proteins to form protein-rich fibers that include selected biochemical cues able to more actively support in vitro cell interaction. In this study, we compared protein-rich fibers fabricated via electrospinning by the blending of poly ε-caprolactone (PCL) with three different proteins, i.e., gelatin, zein, and keratin, respectively. We demonstrated that the peculiar features of the proteins used significantly influence the morphological properties, in terms of fiber size and distribution. Moreover, keratin drastically enhances the fiber hydrophilicity (water contact angle equal to 44.3° ± 3.9°) with positive effects on cell interaction, as confirmed by the higher proliferation of human mesenchymal stem cells (hMSC) until 7 days. By contrast, gelatin and zein not equally contribute to the fiber wettability (water contact angles equal to 95.2° ± 1.2° and 76.3° ± 4.0°, respectively) due to morphological constraints, i.e., broader fiber diameter distribution ascribable to the non-homogeneous presence of the protein along the fibers, or chemical constrains, i.e., large amount of non-polar amino acids. According to in vitro experimental studies, which included SEM and confocal microscopy analyses and vitality assay, we concluded that keratin is the most promising protein to be combined with PCL for the fabrication of biologically instructive fibers for in vitro applications.
Polysaccharides are long monosaccharide units which are emerging as promising materials for tissue engineering and drug delivery applications due to their biocompatibility, mostly good availability ...and tailorable properties, by to the wide possibility to modify chemical composition, structure—i.e., linear chain or branching—and polymer source (animals, plants, microorganisms). For their peculiar behaviour as polyelectrolites, polysaccharides have been applied in various forms, such as injectable hydrogels or porous and fibrous scaffolds—alone or in combination with other natural or synthetic polymers—to design bioinspired platforms for the regeneration of different tissues (i.e., blood vessels, myocardium, heart valves, bone, articular and tracheal cartilage, intervertebral discs, menisci, skin, liver, skeletal muscle, neural tissue, urinary bladder) as well as for encapsulation and controlled delivery of drugs for pharmaceutical devices. In this paper, we focus on the pH sensitive response and degradation behaviour of negative (i.e., alginate) and positive (i.e., chitosan) charged polysaccharides in order to discuss the differences in terms of metabolic activity of polyelectrolytes with different ionic strength for their use in drug delivery and tissue engineering area.
In the last decade, amphiphilic cellulose (AC) is emerging as attractive biomaterial for different therapeutic use, due to its unique chemical and physical properties. Using it as alternative to ...synthetic polymers, AC opens up new avenues to prepare new bio-sustainable materials with low impact in the cellular environment. Herein, most recent methods to synthesize and processing AC materials from different sources-i.e., cellulose nanofibers, bacterial cellulose, cellulose derivatives-will be discussed. By an accurate optimization of morphology and surface chemistry, it is possible to develop innovative amphiphilic platforms, promising for a wide range of biomedical applications, from drug delivery to molecular/particle adsorption.
Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to ...give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.
The accurate mimicking of the fibrillary structure of the extracellular matrix represents one of the critical aspects of tissue engineering, playing a significant role in cell behavior and functions ...during the regenerative process. This work proposed the design of PVA-based multi-component membranes as a valuable and highly versatile strategy to support in vitro regeneration of different tissues. PVA can be successfully processed through electrospinning processes, allowing for the integration of other organic/inorganic materials suitable to confer additive bio-functional properties to the fibers to improve their biological response. It was demonstrated that adding polyethylene oxide (PEO) improves fiber processability; moreover, SEM analyses confirmed that blending PVA with PEO or gelatin enables the reduction of fiber size from 1.527 ± 0.66 μm to 0.880 ± 0.30 μm and 0.938 ± 0.245 μm, respectively, also minimizing defect formation. Furthermore, in vitro tests confirmed that gelatin integration allows the formation of bioactive nanofibers with improved biological response in terms of L929 adhesion and proliferation. Lastly, the processability of PVA fibers with conductive phases such as polyvinylpyrrolidone (PVP) or poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has also been verified. From this perspective, they could be promisingly used to design electroactive composite fibers able to support the regeneration process of electrically stimulated tissues such as nerves or muscles.
Cellulose has received great attention owing to its distinctive structural features, exciting physico-chemical properties, and varied applications. The combination of cellulose and silver ...nanoparticles currently allows to fabricate different promising functional nanocomposites with unique properties. The current work offers a wide and accurate overview of the preparation methods of cellulose-silver nanocomposite materials, also providing a punctual discussion of their potential applications in different fields (i.e., wound dressing, high-performance textiles, electronics, catalysis, sensing, antimicrobial filtering, and packaging). In particular, different preparation methods of cellulose/silver nanocomposites based on in situ thermal reduction, blending and dip-coating, or additive manufacturing techniques were thoroughly described. Hence, the correlations among the structure and physico-chemical properties in cellulose/silver nanocomposites were investigated in order to better control the final properties of the nanocomposites and analyze the key points and limitations of the current manufacturing approaches.
Innovations in drug delivery systems are crucial for enhancing therapeutic efficiency. Our research presents a novel approach based on using electro-fluid dynamic atomization (EFDA) to fabricate ...core-shell monophasic particles (CSMp) from sodium alginate blends of varying molecular weights. This study explores the morphological characteristics of these particles in relation to material properties and process conditions, highlighting their potential in drug delivery applications. A key aspect of our work is the development of a mathematical model that simulates the release kinetics of small molecules, specifically sodium diclofenac. By assessing the diffusion properties of different molecules and gel formulations through transport and rheological models, we have created a predictive tool for evaluating the efficiency of these particles in drug delivery. Our findings underscore two critical, independent parameters for optimizing drug release: the external shell thickness and the diffusivity ratios within the dual layers. This allows for precise control over the timing and intensity of the release profile. This study advances our understanding of EFDA in the fabrication of CSMp and offers promising avenues for enhancing drug delivery systems by tailoring release profiles through particle characteristic manipulation.
In biomedical applications, bacterial cellulose (BC) is widely used because of its cytocompatibility, high mechanical properties, and ultrafine nanofibrillar structure. However, biomedical use of ...neat BC is often limited due to its lack of antimicrobial properties. In the current article, we proposed a novel technique for preparing cationic BC hydrogel through in situ incorporation of cationic water-soluble cellulose derivative, cellulose bearing imidazolium tosylate function group (Cell-IMD), in the media used for BC preparation. Different concentrations of cationic cellulose derivative (2, 4, and 6%) were embedded into a highly inter-twined BC nanofibrillar network through the in situ biosynthesis until forming cationic cellulose gels. Cationic functionalization was deeply examined by the Fourier transform infrared (FT-IR), NMR spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) methods. In vitro studies with L929 cells confirmed a good cytocompatibility of BC/cationic cellulose derivatives, and a significant increase in cell proliferation after 7 days, in the case of BC/Cell-IMD3 groups. Finally, antimicrobial assessment against
,
, and
was assessed, recording a good sensitivity in the case of the higher concentration of the cationic cellulose derivative. All the results suggest a promising use of cationic hybrid materials for biomedical and bio-sustainable applications (i.e., food packaging).
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