Preparation and characterization of chitosan/carboxymethyl pullulan/bioglass composite films for wound healing

Chitosan bioactive glass scaffolds for in vivo subcutaneous implantation, toxicity assessment, and diabetic wound healing upon animal model

This study aims to develop chitosan-bioactive glass (BG) scaffolds for diabetic wound healing, toxicity valuation, and subcutaneous implantation in animals for biocompatibility assessment. The scaffolds were prepared by lyophilization technique. In specific BG without sodium (Na), composited with chitosan for better biological activities. The equipped scaffolds were studied for their physiochemical, biological, in vitro and in vivo performances. The chitosan and chitosan-BG (Na free) scaffolds show reliable biocompatibility, cytocompatibility, anti-oxidant, and tissue regeneration. The biocompatibility, toxicity assessments, and diabetic skin wound healing experiments were examined through in vivo studies using Sprague Dawley rats. The extracted tissue samples were analyzed using hematoxylin-eosin- (H and E) and Masson's trichrome staining. Further, tissue excised after scaffold implantation declared non-toxic, non-allergic, and anti-inflammatory nature of chitosan scaffolds. Moreover, the total ribonucleic acid (RNA) expression levels were measured using reverse transcription-polymerase chain reaction (RT-PCR) for the scaffolds against vascular endothelial growth factor (VEGF), and collagen type one (Col-1) primers. Admirably, the scaffolds achieved the best level of skin wound healing via tissue regeneration by increasing epithetical cell formation and collagen deposition. Thus, the biocompatibility, non-toxicity, anti-inflammatory, and wound healing efficiency proved that the chitosan-BG (Na free) scaffold can be readily substantial for wound healing.

Polysaccharide-Based Coatings as Drug Delivery Systems

Therapeutic polysaccharide-based coatings have recently emerged as versatile strategies to transform a conventional medical implant into a drug delivery system. However, the translation of these polysaccharide-based coatings into the clinic as drug delivery systems still requires a deeper understanding of their drug degradation/release profiles. This claim is supported by little or no data. In this review paper, a comprehensive description of the benefits and challenges generated by the polysaccharide-based coatings is provided. Moreover, the latest advances made towards the application of the most important representative coatings based on polysaccharide types for drug delivery are debated. Furthermore, suggestions/recommendations for future research to speed up the transition of polysaccharide-based drug delivery systems from the laboratory testing to clinical applications are given.

Pullulan-based films impregnated with silver nanoparticles from the Fusarium culmorum strain JTW1 for potential applications in the food industry and medicine

Introduction: Biopolymers, such as pullulan, a natural exopolysaccharide from Aureobasidium pullulans, and their nanocomposites are commonly used in the food, pharmaceutical, and medical industries due to their unique physical and chemical properties. Methods: Pullulan was synthesized by the A. pullulans ATCC 201253 strain. Nanocomposite films based on biosynthesized pullulan were prepared and loaded with different concentrations of silver nanoparticles (AgNPs) synthesized by the Fusarium culmorum strain JTW1. AgNPs were characterized by transmission electron microscopy, Zeta potential measurements, and Fourier-transform infrared spectroscopy. In turn, the produced films were subjected to physico-chemical analyses such as goniometry, UV shielding capacity, attenuated total reflection-Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy, and their mechanical and degradation properties were assessed. The antibacterial assays of the nanoparticles and the nanocomposite films against both food-borne and reference pathogens, including Listeria monocytogenes, Salmonella infantis, Salmonella enterica, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, were performed using standard methods. Results: AgNPs were small (mean 15.1 nm), spherical, and displayed good stability, being coated with protein biomolecules. When used in higher concentrations as an additive to pullulan films, they resulted in reduced hydrophilicity and light transmission for both UV-B and UV-A lights. Moreover, the produced films exhibited a smooth surface. Therefore, it can be concluded that the addition of biogenic AgNPs did not change the morphology and texture of the films compared to the control film. The nanoparticles and nanocomposite films demonstrated remarkable antibacterial activity against both food-borne and reference bacteria. The highest activity of the prepared films was observed against L. monocytogenes. Discussion: The obtained results suggest that the novel nanocomposite films prepared from biosynthesized pullulan and AgNPs can be considered for use in the development of medical products and food packaging. Moreover, this is the first report on pullulan-based nanocomposites with mycogenic AgNPs for such applications.

Chitosan Hydrogel as Tissue Engineering Scaffolds for Vascular Regeneration Applications

Chitosan hydrogels have a wide range of applications in tissue engineering scaffolds, mainly due to the advantages of their chemical and physical properties. This review focuses on the application of chitosan hydrogels in tissue engineering scaffolds for vascular regeneration. We have mainly introduced these following aspects: advantages and progress of chitosan hydrogels in vascular regeneration hydrogels and the modification of chitosan hydrogels to improve the application in vascular regeneration. Finally, this paper discusses the prospects of chitosan hydrogels for vascular regeneration.

Zinc Oxide-Incorporated Chitosan-Poly(methacrylic Acid) Polyelectrolyte Complex as a Wound Healing Material

A novel type of porous films based on the ZnO-incorporated chitosan-poly(methacrylic acid) polyelectrolyte complex was developed as a wound healing material. The structure of porous films was established by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) analysis. Scanning electron microscope (SEM) and porosity studies revealed that the pore size and porosity of the developed films increased with the increase in zinc oxide (ZnO) concentration. The porous films with maximum ZnO content exhibited improved water swelling degree (1400%), controlled biodegradation (12%) for 28 days, a porosity of 64%, and a tensile strength of 0.47 MPa. Moreover, these films presented antibacterial activity toward Staphylococcus aureus and Micrococcus sp. due to the existence of ZnO particles. Cytotoxicity studies demonstrated that the developed films had no cytotoxicity against the mouse mesenchymal stem (C3H10T1/2) cell line. These results reveal that ZnO-incorporated chitosan-poly(methacrylic acid) films could be used as an ideal material for wound healing application.

Vaginal Sheets with Thymbra capitata Essential Oil for the Treatment of Bacterial Vaginosis: Design, Characterization and In Vitro Evaluation of Efficacy and Safety

We aimed to incorporate Thymbra capitata essential oil (TCEO), a potent antimicrobial natural product against bacterial vaginosis (BV)-related bacteria, in a suitable drug delivery system. We used vaginal sheets as dosage form to promote immediate relief of the typical abundant vaginal discharge with unpleasant odour. Excipients were selected to promote the healthy vaginal environment reestablishment and bioadhesion of formulations, while the TCEO acts directly on BV pathogens. We characterized vaginal sheets with TCEO in regard to technological characterization, predictable in vivo performance, in vitro efficacy and safety. Vaginal sheet D.O (acid lactic buffer, gelatine, glycerine, chitosan coated with TCEO 1% w/w) presented a higher buffer capacity and ability to absorb vaginal fluid simulant (VFS) among all vaginal sheets with EO, showing one of the most promising bioadhesive profiles, an excellent flexibility and structure that allow it to be easily rolled for application. Vaginal sheet D.O with 0.32 µL/mL TCEO was able to significantly reduce the bacterial load of all in vitro tested Gardnerella species. Although vaginal sheet D.O presented toxicity at some concentrations, this product was developed for a short time period of treatment, so this toxicity can probably be limited or even reversed when the treatment ends.

New skin tissue engineering scaffold with sulfated silk fibroin/chitosan/hydroxyapatite and its application

Repairing skin wounds has always been challenging in clinical practice. The new skin tissue engineering scaffold provides innovative ways to address these challenges with a good chance of success because of its stable mechanical properties, biodegradability, and antibacterial properties. This paper presents the fabrication and evaluation of a three-dimensional composite scaffold made with sulfated silk fibroin, chitosan, and hydroxyapatite (SSF/CS/HAP). An electron microscope shows that the scaffold has an aperture of 15-20 μm, while an absorption performance test shows that its expansion index reaches 779%. The co-culture of L929 cells and the CCK-8 experiments demonstrated good cell compatibility and low scaffold cytotoxicity, respectively. Meanwhile, in vivo experiments demonstrate that rats with SSF/CS/HAP scaffold-treated neck wounds heal faster. In the wound skin tissue of the SSF/CS/HAP scaffold group, immunohistochemistry indicates a more rapid and mature development of hair follicles. This study successfully developed a novel skin tissue engineering scaffold material with high moisture retention, high tissue compatibility, and low cytotoxicity, demonstrating its ability to improve wound repair with promising potential for tissue engineering applications.

Novel CaO–SiO2–P2O5 Nanobioglass Activated with Hafnium Phthalocyanine

Bioactive glasses are materials which can be used in medicine for regeneration of hard and soft tissues. Their functionalization with active molecules or addition to composites broaden significantly the possible range of glass applications. Hereby, we describe photoactive nanoparticles of CaO–SiO₂–P₂O₅ glass modified with dichlorohafnium (IV) phthalocyanine. The low-temperature, sol–gel based reverse micelle method was proposed for the synthesis, which allowed introduction of metal organic molecules into the glass composition. The morphology, structure, and composition of the material was described showing that spherical but agglomerated glass nanoparticles (size below 100 nm) were obtained in the ternary system. It was also shown that optical properties of the phthalocyanine complex were maintained after immobilization of the dye in the glass. The photoluminescence and generation of singlet oxygen molecules were observed under the light irradiation of the glass.

Engineered Pullulan-Collagen-Gold Nano Composite Improves Mesenchymal Stem Cells Neural Differentiation and Inflammatory Regulation

Tissue repair engineering supported by nanoparticles and stem cells has been demonstrated as being an efficient strategy for promoting the healing potential during the regeneration of damaged tissues. In the current study, we prepared various nanomaterials including pure Pul, pure Col, Pul–Col, Pul–Au, Pul–Col–Au, and Col–Au to investigate their physicochemical properties, biocompatibility, biological functions, differentiation capacities, and anti-inflammatory abilities through in vitro and in vivo assessments. The physicochemical properties were characterized by SEM, DLS assay, contact angle measurements, UV-Vis spectra, FTIR spectra, SERS, and XPS analysis. The biocompatibility results demonstrated Pul–Col–Au enhanced cell viability, promoted anti-oxidative ability for MSCs and HSFs, and inhibited monocyte and platelet activation. Pul–Col–Au also induced the lowest cell apoptosis and facilitated the MMP activities. Moreover, we evaluated the efficacy of Pul–Col–Au in the enhancement of neuronal differentiation capacities for MSCs. Our animal models elucidated better biocompatibility, as well as the promotion of endothelialization after implanting Pul–Col–Au for a period of one month. The above evidence indicates the excellent biocompatibility, enhancement of neuronal differentiation, and anti-inflammatory capacities, suggesting that the combination of pullulan, collagen, and Au nanoparticles can be potential nanocomposites for neuronal repair, as well as skin tissue regeneration in any further clinical treatments.