Protein and polysaccharide-based asymmetric mat with tuned bilayer configuration for enhanced wound healing efficiency

Activation of muscle amine functional groups using eutectic mixture to enhance tissue adhesiveness of injectable, conductive and therapeutic granular hydrogel for diabetic ulcer regeneration

Herein, Polydopamine-modified microgels and microgels incorporated with superficial epoxy groups were synthesized and applied as precursors for the fabrication of four granular hydrogels. To enhance the tissue adhesiveness, a ternary deep eutectic solvent was synthesized to activate the muscle amine functional groups facilitating the formation of robust NC bonds at ambient conditions. At a certain shear rate of 10 s-1, hydrogel DMG displayed a viscosity of 9×103 Pa/s, representing the highest complex viscosity among the tested hydrogels primarily driven by quinone groups in PDA which enhanced reversible interactions, thereby increasing particle cohesion. Moreover, the intersection point escalating from about 4×103 to approximately 9×104 as the concentration of DMG increased from 0 % (for MG) to 70% (7D3MG) by weight. There was a decrease in adhesion strength from 0.45 ± 0.08 N in MG to 0.39 ± 0.16 N, 0.35± 0.18 N, and 0.33 ± 0.15 N for 3D7MG, 7D3MG, and DMG respectively, suggesting that MG was capable of forming numerous covalent bonds, thereby enhancing its adhesion to the substrate. The type of eutectic mixture affected the electrical conductivity and a very important point was the changes in resistance value with time. For MG catalyzed by [DES]AZG, the resistance increased only by 1.3 % (from 3.37 to 3.81 kΩ) at day 3 and 37.09 % (from 3.37 to 4.62 kΩ) at day 5. The 3D7MG hydrogel exhibited superior therapeutic efficacy toward diabetic wound regeneration. The proliferation index value for 3D7MG-[DES]AZG and 3D7MG-[DES]AG were calculated 42.3 % and 58.6 %, respectively, while the control group exhibited a lower value of 37.8 %.

A bi-functional nanofibrous composite membrane for wound healing applications

Various wound dressings have been developed so far for wound healing, but most of them are ineffective in properly reestablishing the skin's structure, which increases infection risks and dehydration. Electrospun membranes are particularly interesting for wound dressing applications because they mimic the extracellular matrix of healthy skin. In this study, a potential wound healing platform capable of inducing synergistic antibacterial and antioxidation activities was developed by incorporating bio-active rosmarinic acid-hydroxyapatite hybrid (HAP-RA) with different contents (0.5, 1, and 1.5 wt.%) into the electrospun polyamide 6 (PA6) nanofibers. Then, polyethylene glycol (PEG) was introduced to the nanofibrous composite to improve the biocompatibility and biodegradability of the dressing. The results indicated that the hydrophilicity, water uptake, biodegradability, and mechanical properties of the obtained PA6/PEG/HAP-RA nanofibrous composite enhanced at 1 wt.% of HAP-RA. The nanofibrous composite had excellent antibacterial activity. The antioxidation potential of the samples was assessed in vitro. The MTT assay performed on the L929 cell line confirmed the positive effects of the nanofibrous scaffold on cell viability and proliferation. According to the results, the PA6/PEG/HAP-RA nanofibrous composite showed the desirable physiochemical and biological properties besides antibacterial and antioxidative capabilities, making it a promising candidate for further studies in wound healing applications.

Biomimetic tri-layered artificial skin comprising silica gel-collagen membrane-collagen porous scaffold for enhanced full-thickness wound healing

Full-thickness wounds are severe cutaneous damages with destroyed self-healing function, which need efficient clinical interventions. Inspired by the hierarchical structure of natural skin, we have for the first time developed a biomimetic tri-layered artificial skin (TLAS) comprising silica gel-collagen membrane-collagen porous scaffold for enhanced full-thickness wound healing. The TLAS with the thickness of 3-7 mm displays a hierarchical nanostructure consisting of the top homogeneous silica gel film, the middle compact collagen membrane, and the bottom porous collagen scaffold, exquisitely mimicking the epidermis, basement membrane and dermis of natural skin, respectively. The 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide/N-Hydroxysuccinimide-dehydrothermal (EDC/NHS-DHT) dual-crosslinked collagen composite bilayer, with a crosslinking degree of 79.5 %, displays remarkable biocompatibility, bioactivity, and biosafety with no risk of hemolysis and pyrogen reactions. Notably, the extra collagen membrane layer provides a robust barrier to block the penetration of silica gel into the collagen porous scaffold, leading to the TLAS with enhanced biocompatibility and bioactivity. The full-thickness wound rat model studies have indicated the TLAS significantly facilitates the regeneration of full-thickness defects by accelerating re-epithelization, collagen deposition and migration of skin appendages. The highly biocompatible and bioactive tri-layered artificial skin provides an improved treatment for full-thickness wounds, which has great potential in tissue engineering.

Functionally multifaceted alginate/curdlan/agarose-based bilayer fibro-porous dressings for addressing full-thickness diabetic wounds

Full-thickness diabetic wounds are chronic injuries characterized by bleeding, excessive exude, and prolonged inflammation. Single-layer dressings fail to address their disturbed pathophysiology. Therefore, bilayer dressings with structural and compositional differences in each layer have gained attention. We hypothesized that natural polymer (alginate, curdlan, and agarose) based bilayer dressings with inherent healing properties could effectively resolve these issues. Hence, bilayer dressings were fabricated by electrospinning curdlan/agarose/ polyvinyl alcohol blend (top layer) on an alginate/agarose/polyvinyl alcohol-based lyophilized porous (bottom) layer. Ciprofloxacin was incorporated in both layers as a potential antibacterial drug. The bilayer dressing exhibited high swelling (~1300 %), biocompatibility (>90 % with NIH 3T3 and L929 mouse fibroblasts), and hemocompatibility (hemolysis <5 %). In vitro, scratch assay revealed a faster wound closure (~ 95-100 %) than control. Inhibition zone assay revealed antibacterial activity against Staphylococcus aureus and Escherichia coli. Real-time (in vitro) gene expression experiments performed using human THP-1 macrophages exhibited a significant increase in anti-inflammatory cytokines (4.51 fold in IL-10) and a decrease in pro-inflammatory cytokines (1.42 fold in IL-6) in comparison to lipopolysaccharide. Thus, fabricated dressings with high swelling, hemostatic, immunomodulatory, and antibacterial characteristics can serve as potential multifunctional and sustainable templates for healing full-thickness diabetic wounds.

Electrospun nylon 6/hyaluronic acid/chitosan bioactive nanofibrous composite as a potential antibacterial wound dressing

Hyaluronic acid (HA) and chitosan (CS), as natural biomaterials, display excellent biocompatibility and stimulate the growth and proliferation of fibroblasts. Furthermore, nylon 6 (N6) is a low-cost polymer with good compatibility with human tissues and high mechanical stability. In this study, HA and CS were applied to modify N6 nanofibrous mat (N6/HA/CS) for potential wound dressing. N6/HA/CS nanofibrous composite mats were developed using a simple one-step electrospinning technique at different CS concentrations of 1, 2, and 3 wt%. The results demonstrated that incorporating HA and CS into N6 resulted in increased hydrophilicity, as well as favorable physical and mechanical properties. In addition, the minimum inhibitory concentration and (MIC) optical density techniques were used to determine the antibacterial properties of N6/HA/CS nanofibrous composite mats, and the results demonstrated that the composites could markedly inhibit the growth of Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. Because of its superior mechanical properties, substantial antimicrobial effects, and hydrophilic surface, N6/HA/CS at 2 wt% of CS (N6/HA/CS2) was chosen as the most suitable nanofibrous mat. The swelling, porosity, gel content, and in vitro degradation studies imply that N6/HA/CS2 nanofibrous composite mat has proper moisture retention and biodegradability. Furthermore, the N6/HA/CS2 nanofibrous composite mat was discovered to be nontoxic to L929 fibroblast cells and to even improve cell proliferation. Based on the findings, this research offers a simple and rapid method for creating material that could be utilized as prospective wound dressings in clinical environments.

Therapeutic effects of electrospun chitosan nanofibers on animal skin wounds: A systematic review and meta-analysis

Electrospun chitosan nanofibers (QSNFs) enhance the healing process by mimicking skin structure and function. The aim of this study was to analyze the therapeutic effects of QSNFs application on animal skin wounds to identify a potential direction for translational research in dermatology. The PRISMA methodology and the PICO scheme were used. A random effects model and mean difference analysis were applied for the meta-analysis. A meta-regression model was constructed, risk of bias was determined, and methodological quality assessment was performed. Of the 2370 articles collected, 54 studies were selected based on the inclusion and exclusion criteria. The wound healing area was used for building models on the 3rd, 7th, and 14th days of follow-up; the results were - 10.4% (95% CI, -18.2% to -2.6%, p = 0.001), -21.0% (95% CI, -27.3% to -14.7%, p = 0.001), and - 14.0% (95% CI, -19.1 to -8.8%, p = 0.001), respectively. Antioxidants and synthetic polymers combined with QSNFs further reduced skin wound areas (p < 0.05). The results show a more efficient reduction in wound area percentages in experimental groups than in control groups, so QSNFs could potentially be applied in translational human medicine research.

State-of-the-Art Review of Advanced Electrospun Nanofiber Composites for Enhanced Wound Healing

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.

Bletilla striata composite nanofibrous membranes prepared by emulsion electrospinning for enhanced healing of diabetic wounds

Diabetic wounds impose enormous distress and financial burden on patients, and finding effective dressings to manage wounds is critical. As a Chinese herbal medicine with a long history of Clinical application, Bletilla striata has significant medicinal effects in the therapy of various wounds. In this study, PLA and the pharmacodynamic substances of Bletilla striata were prepared into fibrous scaffolds by emulsion electrospinning technology for the management of diabetic wounds in mice. The results of scanning electron microscopy showed that the core-shell structure fibre was successfully obtained by emulsion electrospinning. The fibre membrane exhibited excellent water absorption capability and water vapor transmission rate, could inhibit the growth of Staphylococcus aureus and Pseudomonas aeruginosa, had good compatibility, and achieved excellent healing effect on diabetic wounds. Especially in the in vivo wound healing experiment, the wound healing rate of composite fibre membrane treatment reached 98.587 ± 2.149% in 16 days. This work demonstrated the good therapeutic effect of the developed fibrous membrane to diabetic wound, and this membrane could be potentially applied to chronic wound healing.

Development of an antibacterial and antioxidative nanofibrous membrane using curcumin-loaded halloysite nanotubes for smart wound healing: In vitro and in vivo studies

Endowing wound dressings with drug delivery capability is a suitable strategy to transfer medicinal compounds locally to damaged skin layers. These dressings are especially useful for accelerating the healing rate in the cases of long-term treatment, and adding more functionalities to the platform. In this study, a wound dressing composed of polyamide 6, hyaluronic acid, and curcumin-loaded halloysite nanotubes (PA6/HA/HNT@Cur) was designed and fabricated for wound healing applications. The physicochemical properties of this platform were investigated through Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. Moreover, wettability, tensile strength, swelling, and in vitro degradation were assessed. The HNT@Cur was incorporated in the fibers in three concentrations and 1 wt% was found as the optimum concentration yielding desirable structural and mechanical properties. The loading efficiency of Cur on HNT was calculated to be 43 ± 1.8%, and the release profiles and kinetics of nanocomposite were investigated at physiological and acidic pH. In vitro antibacterial and antioxidation studies showed that the PA6/HA/HNT@Cur mat had strong antibacterial and antioxidation activities against gram-positive and -negative pathogens and reactive oxygen species, respectively. Desirable cell compatibility of the mat was found through MTT assay against L292 cells up to 72 h. Finally, the efficacy of the designed wound dressing was evaluated in vivo; after 14 days, the results indicated that the wound size treated with the nanocomposite mat significantly decreased compared to the control sample. This study proposed a swift and straightforward method for developing materials that might be utilized as wound dressings in clinical settings.

The Use of Proteins, Lipids, and Carbohydrates in the Management of Wounds

Despite the fact that skin has a stronger potential to regenerate than other tissues, wounds have become a serious healthcare issue. Much effort has been focused on developing efficient therapeutical approaches, especially biological ones. This paper presents a comprehensive review on the wound healing process, the classification of wounds, and the particular characteristics of each phase of the repair process. We also highlight characteristics of the normal process and those involved in impaired wound healing, specifically in the case of infected wounds. The treatments discussed here include proteins, lipids, and carbohydrates. Proteins are important actors mediating interactions between cells and between them and the extracellular matrix, which are essential interactions for the healing process. Different strategies involving biopolymers, blends, nanotools, and immobilizing systems have been studied against infected wounds. Lipids of animal, mineral, and mainly vegetable origin have been used in the development of topical biocompatible formulations, since their healing, antimicrobial, and anti-inflammatory properties are interesting for wound healing. Vegetable oils, polymeric films, lipid nanoparticles, and lipid-based drug delivery systems have been reported as promising approaches in managing skin wounds. Carbohydrate-based formulations as blends, hydrogels, and nanocomposites, have also been reported as promising healing, antimicrobial, and modulatory agents for wound management.

Control of eriocitrin release from pH-sensitive gelatin-based microgels to inhibit α-glucosidase: an experimental and computational study

α-Glucosidase is among the intestinal epithelial enzymes that produce absorbable glucose in the final stage of glycan catabolism. It leads to an increase in blood glucose levels as a result of high glucose uptake in diabetic patients. However, inhibition of this essential biochemical process can be a useful therapeutic approach to diabetes mellitus (DM). Eriocitrin (ER) is an abundant "flavanone glycoside" in citrus fruits with rich antioxidant properties whose effects on α-Glu inhibition in the small intestine remain to be determined. Herein, pH-sensitive microgels (MGs) were designed based on cross-linked methacrylate with acrylamide (AM) and acrylic acid (AAc) (molar ratio 70 : 30 of AAc : AM) as a controlled release system for sustained delivery of ER into the small intestine. The presence of amide and acrylate in MGs and the mechanical resistance were determined using FT-IR spectroscopy, rheology, and viscoelastometry. In vitro experiments showed that MGs could protect ER against diffusion in the gastric location and adjust its release in the intestinal milieu. The intestinal α-Glu activity was inhibited by ER (IC₅₀ value of 12.50 ± 0.73 μM) in an uncompetitive dose-dependent manner. The presence of ER altered the structure of α-Glu and reduced the hydrophobic pockets of the enzyme. Molecular docking analysis along with molecular dynamics simulation displayed that ER-α-Glu formation is directed by hydrogen binding with Asp69, Asp215, Glu411, Asp307, and Tyr347 residues. Moreover, in vivo assessment showed that rat blood glucose concentration decreased after ER administration compared with the control group. The results highlight that ER-loaded-MGs can be considered as a useful releasing strategy in treating DM via α-Glu inhibition.