Angiogenesis, hemocompatibility and bactericidal effect of bioactive natural polymer-based bilayer adhesive skin substitute for infected burned wound healing

Biological Coatings: Advanced Strategies Driving Multifunctionality and Clinical Potential in Dermal Substitutes

Skin tissue defects caused by various acute and chronic etiologies frequently occur in clinical medicine. Traditional surgical repair methods have certain limitations, while dermal substitutes combined with skin grafting have become an alternative to conventional surgery. Biological coatings, by loading bioactive substances such as polysaccharides and proteins, or by using bioactive substances as carriers, can promote cell adhesion, proliferation, and differentiation. This optimizes the mechanical properties and biocompatibility of the substitutes, enhances their antibacterial properties, and improves their feasibility for clinical application. This paper explores various common biological coating materials and the construction methods used in the field of dermal substitutes. It highlights the importance and necessity of biological coatings in the development of multifunctional designs for dermal substitutes. By summarizing the current research, this paper aims to offer new insights and references for the multifunctional design and clinical application of dermal substitutes.

3D printed Aloe barbadensis loaded alginate-gelatin hydrogel for wound healing and scar reduction: In vitro and in vivo study

Wounds are one of the most critical clinical issues in plastic surgery repair and restoration. Conventional wound dressing materials cannot absorb enough wound exudates and shield the site from microbial infection. Also, despite their healing prowess, bioactive molecules from medicinal plants are less bioavailable at the wound sites. This study developed a 3D-printed hydrogel of sodium alginate and gelatin loaded with freeze-dried Aloe barbadensis extract for enhanced wound healing. The hydrogel was hydrophilic and showed an average pore size of 163.66 ± 14.45 μm, moderate swellability, and ideal mechanical properties with tensile strength(σ) of 16.39 ± 0.98 MPa, and Young's modulus of 17.43 ± 1.41 MPa. They showed potential antibacterial activity against Staphylococcus aureus (87.7 ± 4 % inhibition) and Pseudomonas aeruginosa (84.4 ± 6 % inhibition). These hydrogels were hemocompatible, biocompatible, and biodegradable. Cell cytotoxicity assay and scratch assay showed effective Normal Human Dermal Fibroblast cells (NHDF) viability, proliferation, and migration on the hydrogel. In vivo studies of the 3D-printed hydrogel demonstrated significantly improved wound closure, reduced wound contraction, enhanced epithelial regeneration with minimal inflammation, and decreased scar formation after 14 days of treatment. Therefore, this 3D-printed hydrogel can be promising for wound healing with scar reduction.

Physicochemically Cross-linked Injectable Hydrogel: an Adhesive Skin Substitute for Burned Wound Therapy

Burns carry a large surface area, varying in shapes and depths, and an elevated risk of infection. Regardless of the underlying etiology, burns pose significant medical challenges and a high mortality rate. Given the limitations of current therapies, tissue-engineering-based treatments for burns are inevitable. Herein, we developed a natural physicochemically cross-linked adhesive injectable skin substitute (SS) comprising chitosan (Ch) and silk fibroin (SF), cross-linked with tannic acid (TA) through hydrogen bonding, and incorporated with fresh platelet-rich fibrin (FPRF). SF was also chimerically cross-linked with riboflavin (RF) under visible light to ensure desirable biodegradability rate and nontoxicity. Double cross-linked SS exhibited a semibilayer (SBSS) structure with smaller pores in the upper layer. In the CaCl2-treated FPRF, the activated platelets augmented vascular endothelial growth factor (VEGF) and platelet-derived GF (PDGF) release. The resultant SBSS possessed optimal adhesion, hemocompatibility, and significant antibacterial and antioxidant activities (P ≤ 0.05). The rat liver injury model confirmed the rapid hemostatic effect of SBSS. Furthermore, the bottom layer of SBSS promoted L929 fibroblast growth, proliferation, and migration. SBSS-treated wounds showed lower inflammatory cells, earlier epithelialization, significant angiogenesis, and faster healing. The proposed SBSS could be an ideal remedy for burn wound therapy.

Recent Advances in Asymmetric Wettability Dressings for Wound Exudate Management

The management of wound exudate is of vital importance for wound healing. Exudate accumulation around wound prolongs inflammation and hinders healing. Although traditional dressings can absorb wound exudate, they are unable to drain exudate in time, often resulting in a poor feature with wound healing. In recent years, the appearance of asymmetric wettability dressings has shown great potential in exudate management. Here, we summarize the latest progress of 3 kinds of asymmetric wettability wound dressings in exudate management, including Janus structure, sandwich structure, and gradient structure. The most common Janus structural dressing among asymmetric wettability dressings is highlighted from 2 aspects: single-layer modified Janus structure and double-layer Janus structure. The challenges faced by asymmetric wettability wound dressings are discussed, and the developing trends of smart wound dressings in this field are prospected.

Titanium dioxide nanoparticles: a promising candidate for wound healing applications

Effective wound management and treatment are crucial in clinical practice, yet existing strategies often fall short in fully addressing the complexities of skin wound healing. Recent advancements in tissue engineering have introduced innovative approaches, particularly through the use of nanobiomaterials, to enhance the healing process. In this context, titanium dioxide nanoparticles (TiO2 NPs) have garnered attention due to their excellent biological properties, including antioxidant, anti-inflammatory, and antimicrobial properties. Furthermore, these nanoparticles can be modified to enhance their therapeutic benefits. Scaffolds and dressings containing TiO2 NPs have demonstrated promising outcomes in accelerating wound healing and enhancing tissue regeneration. This review paper covers the wound healing process, the biological properties of TiO2 NPs that make them suitable for promoting wound healing, methods for synthesizing TiO2 NPs, the use of scaffolds and dressings containing TiO2 NPs in wound healing, the application of modified TiO2 NPs in wound healing, and the potential toxicity of TiO2 NPs.

Adhesive, Stretchable, and Photothermal Antibacterial Hydrogel Dressings for Wound Healing of Infected Skin Burn at Joints

Dressings for infectious skin burn wounds at joints should have therapeutic functions as well as high tissue-adhesion, stretching, and self-healing properties. This makes it difficult for most hydrogel dressings to simultaneously meet the above-mentioned requirements. In this study, poly(vinyl alcohol), anhydrous sodium borax, epigallocatechin gallate, and copper chloride were used to prepare a hydrogel dressing (PBEC) for the infected burn wound healing at joints. The PBEC hydrogel can adhere to a variety of substrates, has a stretching capacity, and quickly self-healing after being damaged. Additionally, the PBEC hydrogel has the properties of reactive oxygen species scavenging, photothermal sterilization, hemostatic ability, and biocompatibility. Finally, the hydrogel could accelerate the process of wound healing in vivo, especially with the assistance of near-infrared radiation. Therefore, the hydrogel dressing shows great potential for clinical application in the healing of infected burn wounds at joints.

3D Printing-Based Hydrogel Dressings for Wound Healing

Skin wounds have become an important issue that affects human health and burdens global medical care. Hydrogel materials similar to the natural extracellular matrix (ECM) are one of the best candidates for ideal wound dressings and the most feasible choices for printing inks. Distinct from hydrogels made by traditional technologies, which lack bionic and mechanical properties, 3D printing can promptly and accurately create hydrogels with complex bioactive structures and the potential to promote tissue regeneration and wound healing. Herein, a comprehensive review of multi-functional 3D printing-based hydrogel dressings for wound healing is presented. The review first summarizes the 3D printing techniques for wound hydrogel dressings, including photo-curing, extrusion, inkjet, and laser-assisted 3D printing. Then, the properties and design approaches of a series of bioinks composed of natural, synthetic, and composite polymers for 3D printing wound hydrogel dressings are described. Thereafter, the application of multi-functional 3D printing-based hydrogel dressings in a variety of wound environments is discussed in depth, including hemostasis, anti-inflammation, antibacterial, skin appendage regeneration, intelligent monitoring, and machine learning-assisted therapy. Finally, the challenges and prospects of 3D printing-based hydrogel dressings for wound healing are presented.

Antioxidant hydrogel from poly(aspartic acid) and carboxymethylcellulose with quercetin loading as burn wound dressing

Susceptibility to infection and excessive accumulation of reactive oxygen species (ROS) are the greatest obstacles for burn wound healing. In this research, the 5-aminosalicylic acid (ASA) grafted poly(aspartic hydrazide) (PASH) was synthesized by successive ploysuccinimide (PSI) ring opening reaction and reacted with oxidized carboxymethyl cellulose (DCMC) to fabricate biodegradable hydrogel through Schiff-base cross-linking. Moreover, the hydrogel was loaded with quercetin (QT) to enhance its anti-inflammatory performance. The ASA moiety endowed the hydrogel with the free radical scavenging ability and mussel inspired tissue adhesion to maintain the healing bioenvironment of the wound. The loading of QT gave the hydrogel more phenolic hydroxy group and further enhanced the antioxidant capacity of the hydrogel. The in vitro experiment revealed the grafted ASA moiety and the loaded QT greatly enhanced the ROS elimination property and antibacterial property. Moreover, the QT loaded hydrogel accelerated the burn wound repairing rate in the in vivo mice model. Based on above result, the PASH/DCMC could act as a new platform for QT loading to promote the burn wound repairing.

Three-dimensional printed polyelectrolyte construct containing mupirocin-loaded quaternized chitosan nanoparticles for skin repair

Despite substantial advancements in wound dressing development, effective skin repair remains a significant challenge, largely due to the persistent issue of recurrent infections. Three-dimensional printed constructs that integrate bioactive and antibacterial agents hold significant potential to address this challenge. In this study, a 3D-printed hydrogel scaffold composed of polyallylamine hydrochloride (PAH) and pectin (Pc), incorporated with mupirocin (Mp)-loaded quaternized chitosan nanoparticles (QC NPs) was fabricated. The primary objective of this study was to facilitate a controlled and sustained release of Mp via the QC NPs. The average size of QC-Mp nanoparticles was measured to be 66.05 nm and the average strand diameter and pore size of the 3D-printed construct were measured as 147.22 ± 5.83 and 388.44 ± 14.50 μm, respectively. The hemolysis rate of all scaffolds was below 2 %, indicating that they can be classified as non-hemolytic materials with sufficient blood compatibility. The PAH-Pc/QC-Mp scaffold exhibited significant antibacterial activity, enhanced cell viability in HaCat cells, sustained Mp release until day 7 (⁓60 %), and in-vivo wound healing promotion by stimulation of human keratinocytes. In conclusion, the proposed biocompatible construct demonstrates significant potential for the treatment of chronic and infected wounds by preventing infection and promoting accelerated wound healing.

Exos‐Loaded Gox‐Modified Smart‐Response Self‐Healing Hydrogel Improves the Microenvironment and Promotes Wound Healing in Diabetic Wounds

Wound management has always been a challenge in the clinical treatment of diabetes. In this study, glucose oxidase (GOx) is grafted onto natural pullulan polysaccharides, and oxidization is carried out to form a self‐healing hydrogel using carboxymethyl chitosan by means of reversible Schiff base covalent bonding. The smart‐response drug release properties of this natural self‐healing hydrogel are demonstrated in diabetic wounds by taking advantage of two key factors, namely the pH‐responsive nature of Schiff base bonding and the fact that GOx reduces the pH in diabetic wounds. To further enhance the biological functions of the hydrogel dressing, exosomes (Exos) are introduced into the hydrogel system. The GOx present in the hydrogel system improves the high‐glucose microenvironment of diabetic wounds, releasing H2O2 to impart antimicrobial effects, and ensuring that the hydrogel realizes a smart‐response function. The carboxymethyl chitosan component used to construct the hydrogel plays an effective antibacterial role. Moreover, the Exos loaded into the hydrogel effectively promotes neovascularization of the wound. The Exos also regulates macrophage polarization and reduces the levels of persistent inflammation in diabetic wounds. These results suggest that this smart responsive, multifunctional, and self‐healing hydrogel dressing is ideal for the management of diabetic wounds.

Exploring nanobioceramics in wound healing as effective and economical alternatives

Wound healing is a sophisticated process for which various treatment methods have been developed. Bioceramics with the ability to release inorganic ions in biological environments play a crucial role in cellular metabolism and exhibit bactericidal activity, contributing to numerous physiological processes. Their multifaceted roles in biological systems highlight their significance. The release of different metallic ions from bioceramics enables the repair of both hard and soft tissues. These ions may be effective in cell motility, proliferation, differentiation, adhesion, angiogenesis, and antibiosis. Unlike conventional medications, the bioactivity and antibacterial properties of bioceramics are typically not associated with side effects or bacterial resistance. Bioceramics are commonly recognized for their capcity to facilitate the healing of hard tissues due to their exceptional mechanical properties. In this review, we first explore wound treatment and its prevalent methods, and subsequently, we discuss the application of three primary categories of bioceramics-oxide ceramics, silicate-based ceramics, and calcium-phosphate ceramics-in the context of wound treatment. This review introduces bioceramics as a cost-effective and efficient alternative for wound repair. Our aim is to inspire researchers to incorporate bioceramics with other biomaterials to achieve enhanced, economical, expedited, and safer wound healing.

Multifunctional Nanofiber Membranes Constructed by Microfluidic Blow-Spinning to Inhibit Scar Formation at Early Intervention Stage

Pathological scarring has been a challenge in skin injury repair since ancient times, and prophylactic treatment in the early stages of wound healing usually results in delayed wound healing. In this study, poly(ethylene oxide) (PEO) and chitosan (CTS) were used as carrier materials to construct multifunctional pirfenidone (PFD)/CTS/PEO (PCP) nanofiber membranes (NFMs) loaded with PFD by microfluidic blow-spinning (MBS). MBS is a good method for quickly, safely, and greenly constructing large-area manufacturing of inexpensive NFMs. PCP NFMs were uniform in external morphology, with diameters ranging from 200 to 500 nm. The encapsulation efficiency of the drug-loaded PCP NFMs was above 80%, which had a good slow release, visualization, water absorption, and biocompatibility. The inhibitory effect of PCP NFMs on normal human dermal fibroblasts was dose-dependent and inhibited the expression of the transforming growth factor-β1/SMAD family member 3 (TGF-β1/SMAD3) signaling pathway. PCP NFMs showed significant antibacterial effects against both Staphylococcus aureus and Escherichia coli. In the rabbit ear scar experiment, the wound healed about 70% on day 5 and almost completely on day 10 after PCP-3 NFMs treatment, with the thinnest scar tissue, skin color, tenderness close to normal tissue, and a Vancouver scar scale score of less than 5. PCP-3 NFMs had good effects on anti-inflammatory, wound healing, and collagen-I deposition reducing effects. In conclusion, PCP-3 NFMs can both promote wound healing and intervene to inhibit pathological scarring in advance, making them a potential multifunctional wound dressing for early prevention and treatment of pathological scarring.

Biomedical application of materials for external auditory canal: History, challenges, and clinical prospects

Biomaterials play an integral role in treatment of external auditory canal (EAC) diseases. Regarding the special anatomic structure and physiological characteristics of EAC, careful selection of applicable biomaterials was essential step towards effective management of EAC conditions. The bioactive materials can provide reasonable biocompatibility, reduce risk of host pro-inflammatory response and immune rejection, and promote the healing process. In therapeutic procedure, biomaterials were employed for covering or packing the wound, protection of the damaged tissue, and maintaining of normal structures and functions of the EAC. Therefore, understanding and application of biomaterials was key to obtaining great rehabilitation in therapy of EAC diseases. In clinical practice, biomaterials were recognized as an important part in the treatment of different EAC diseases. The choice of biomaterials was distinct according to the requirements of various diseases. As a result, awareness of property regarding different biomaterials was fundamental for appropriate selection of therapeutic substances in different EAC diseases. In this review, we firstly introduced the characteristics of EAC structures and physiology, and EAC pathologies were summarized secondarily. From the viewpoint of biomaterials, the different materials applied to individual diseases were outlined in categories. Besides, the underlying future of therapeutic EAC biomaterials was discussed.

Dual-functional gallium/chitosan/silk/umbilical cord mesenchymal stem cell exosome sponge scaffold for diabetic wound by angiogenesis and antibacteria

The treatment of diabetic wounds possessed significant challenges in clinical practice, which was accompanied with continuous infection, inflammation, and limited angiogenesis. Current wound dressings used for diabetic wound healing struggle to address these issues simultaneously. Therefore, Ga3+ was added to the chitosan/silk solution to confer potent antibacterial properties. Subsequently, umbilical cord mesenchymal stem cell exosomes (UCSC-Exo) were integrated into the gallium/chitosan/silk solution to enhance its angiogenesis-inducing activity. The mixture was lyophilized to prepare gallium/chitosan/silk/exosome sponge scaffolds (Ga/CSSF-Exo sponge scaffolds). The experiments of In vitro and in vivo demonstrated that Ga/CSSF-Exo sponge scaffolds exhibited sustained release of Ga3+ and bioactive exosomes, which effectively exerted continuous antibacterial effects and promoted angiogenesis. In diabetic rat wound models, Ga/CSSF-Exo sponge scaffolds facilitated angiogenesis, suppressed bacterial growth and inflammation, as well as promoted collagen deposition and re-epithelialization of wounds. Collectively, our findings suggested that Ga/CSSF-Exo held excellent potential for diabetic wound healing.

Near-Infrared Responsive Nanocomposite Hydrogel Dressing with Anti-Inflammation and Pro-Angiogenesis for Wound Healing

Anti-inflammatory and angiogenesis are two important factors in wound healing. Wound dressings with anti-inflammation and vascularization are essential to address complex interventions, expensive treatments, and uncontrolled release mechanisms. Based on the above considerations, we designed a near-infrared (NIR)-responsive hydrogel dressing, which is composed of mPDA-DFO@LA nanoparticles (mPDA: dopamine hydrochloride nanoparticles, DFO: deferoxamine, LA: lauric acid), valsartan (abbreviated as Va), and dopamine-hyaluronic acid hydrogel. The hydrogel dressing demonstrated injectability, bioadhesive, and photothermal properties. The results indicated the obtained dressing by releasing Va can appropriately regulate macrophage phenotype transformation from M1 to M2, resulting in an anti-inflammatory environment. In addition, DFO encapsulated by LA can be sustainably released into the wound site by NIR irradiation, which further prevents excessive neovascularization. Notably, the results in vivo indicated the mPDA-DFO@LA/Va hydrogel dressing significantly enhanced wound recovery, achieving a healing rate of up to 96% after 11 days of treatment. Therefore, this NIR-responsive hydrogel dressing with anti-inflammation, vascularization, and on-demand programmed drug release will be a promising wound dressing for wound infection.

Insect chitosan/pullulan/gallium photo-crosslinking hydrogels with multiple bioactivities promote MRSA-infected wound healing

Methicillin-resistant Staphylococcus aureus (MRSA) and other drug-resistant bacteria have become more common in recent years, which has made it extremely difficult to treat and heal many different kinds of wounds and caused enormous financial losses. Because of its unique "Trojan horse" function, Ga3+ has been recognized as a new possible candidate for inhibiting and eradicating drug-resistant bacteria. Furthermore, natural polysaccharide materials with outstanding biological characteristics, such as insect chitosan (CS) and pullulan (PUL), have attracted significant interest. In this study, we used quaternized-catechol chitosan (QDCS-PA), methacrylate-dialdehyde pullulan (DPUL-GMA), and gallium ion (Ga) to create a multi-crosslinked photo-enhanced hydrogel (Q-D/Ga/UV) with antimicrobial, hemostatic, self-healing, and injectable properties for promoting MRSA-infected wound healing. In vitro, the Q-D/Ga/UV hydrogels demonstrated good mechanical properties, antioxidant capabilities, biocompatibility, hemostatic properties, and antibacterial activity. The addition of gallium ions enhanced the hydrogels' mechanical properties, hemostatic capabilities, antibacterial activity, and ability to induce wound healing. Q-D/Ga/UV hydrogel significantly promoted wound contraction, collagen deposition, and angiogenesis while also suppressing inflammation in a whole-skin wound model of MRSA-infected rats. In conclusion, Q-D/Ga/UV hydrogels demonstrate significant promise for healing wounds infected with drug-resistant bacteria.

Multifunctional polysaccharide/metal/polyphenol double-crosslinked hydrogel for infected wound

Bacterial-infected wounds present a significant challenge in the medical field, posing a severe threat to public health. Traditional wound dressings have limited efficacy in treating bacterial-infected wounds, and antibiotics suffer from cytotoxicity and drug resistance. Consequently, an urgent requirement exists for developing multifunctional wound dressings capable of providing superior antimicrobial activity and expediting wound repair. In recent years, chitosan-based natural polysaccharide hydrogels have garnered attention for their biocompatibility, antimicrobial properties, and ability to aid in hemostasis. This study presents the development of a multi-functional, bi-dynamic network hydrogel for the treatment of wounds infected with bacteria. The hydrogel consists of a backbone of chitosan grafted with chlorogenic acid (CA-ECS), oxidized pullulan polysaccharides (OP), and zinc ions (Zn2+). The CA-ECS/OP/Zn2+ hydrogel displayed strong adhesion, good injectability, and high mechanical strength and was biodegradable and biocompatible. Furthermore, adding Zn2+ and CA enhanced the hydrogel's mechanical properties and antioxidant and antimicrobial activities. In a rat model of full-thickness skin wounds infected with S. aureus, the CA-ECS/OP/Zn2+ hydrogel demonstrated great anti-inflammatory, angiogenic, and folliculogenic properties, resulting in accelerated wound healing. The CA-ECS/OP/Zn2+ hydrogel has great potential for treating bacterial-infected wounds.

Graphene oxide-encapsulated baghdadite nanocomposite improved physical, mechanical, and biological properties of a vancomycin-loaded PMMA bone cement

Polymethyl methacrylate (PMMA) bone cement is commonly used in orthopedic surgeries to fill the bone defects or fix the prostheses. These cements are usually containing amounts of a nonbioactive radiopacifying agent such as barium sulfate and zirconium dioxide, which does not have a good interface compatibility with PMMA, and the clumps formed from these materials can scratch metal counterfaces. In this work, graphene oxide encapsulated baghdadite (GOBgh) nanoparticles were applied as radiopacifying and bioactive agent in a PMMA bone cement containing 2 wt.% of vancomycin (VAN). The addition of 20 wt.% of GOBgh (GOBgh20) nanoparticles to PMMA powder caused a 33.6% increase in compressive strength and a 70.9% increase in elastic modulus compared to the Simplex® P bone cement, and also enhanced the setting properties, radiopacity, antibacterial activity, and the apatite formation in simulated body fluid. In vitro cell assessments confirmed the increase in adhesion and proliferation of MG-63 cells as well as the osteogenic differentiation of human adipose-derived mesenchymal stem cells on the surface of PMMA-GOBgh20 cement. The chorioallantoic membrane assay revealed the excellent angiogenesis activity of nanocomposite cement samples. In vivo experiments on a rat model also demonstrated the mineralization and bone integration of PMMA-GOBgh20 cement within four weeks. Based on the promising results obtained, PMMA-GOBgh20 bone cement is suggested as an optimal sample for use in orthopedic surgeries.

MOF/MXene-loaded PVA/chitosan hydrogel with antimicrobial effect and wound healing promotion under electrical stimulation and improved mechanical properties

Electrical stimulation modulates cell behavior and influences bacterial activity, so highly conductive, antimicrobial hydrogels are suitable for promoting wound healing. In this study, highly conductive and antimicrobial Ti3C2Tx (MXene) hydrogels composed of chitosan and poly(vinyl alcohol) and AgCu- H2PYDC MOF were developed. In PVACS/MOF/MXene (PCMM) hydrogels, the MXene layer acts as an electrical conductor. The electrical conductivity is 0.61 ± 0.01 S·cm-1. PCMM hydrogels modulate cell behavior and provide ES antimicrobial capacity under ES at 1 V. The metal ions of MOF form coordination with chitosan molecules and increase the cross-linking density between chitosan molecules, thus improving the mechanical properties of the hydrogel (tensile strength 0.088 ± 0.04 MPa, elongation at break 233 ± 11 %). The PCMM gels had good biocompatibility. The PCMM hydrogels achieved 100 % antibacterial activity against E. coli and S. aureus for 12 h. 1 V electrical stimulation of PCMM hydrogel accelerated the wound healing process in mice by promoting cell migration and neovascularization, achieving 97 ± 0.4 % wound healing on day 14. The hydrogel dressing PCMM-0.1 with MOF addition of 0.1 % had the best wound healing promoting effect and which is a promising dressing for promoting wound healing and is a therapeutic strategy worth developing.

A double-layer cellulose/pectin-soy protein isolate-pomegranate peel extract micro/nanofiber dressing for acceleration of wound healing

Multi-layered wound dressings can closely mimic the hierarchical structure of the skin. Herein, a double-layer dressing material is fabricated through electrospinning, comprised of a nanofibrous structure as a healing-support layer or the bottom layer (BL) containing pectin (Pec), soy protein isolate (SPI), pomegranate peel extract (P), and a cellulose (Cel) microfiber layer as a protective/monitoring layer or top layer (TL). The formation of a fine bilayer structure was confirmed using scanning electron microscopy. Cel/Pec-SPI-P dressing showed a 60.05 % weight loss during 7 days of immersion in phosphate buffered solution. The ultimate tensile strength, elastic modulus, and elongation at break for different dressings were within the range of 3.14-3.57 MPa, 32.26-36.58 MPa, and 59.04-63.19 %, respectively. The release of SPI and phenolic compounds from dressings were measured and their antibacterial activity was evaluated. The fabricated dressing was non-cytotoxic following exposure to human keratinocyte cells. The Cel/Pec-SPI-P dressing exhibited excellent cell adhesion and migration as well as angiogenesis. More importantly, in vivo experiments on Cel/Pec-SPI-P dressings showed faster epidermal layer formation, blood vessel generation, collagen deposition, and a faster wound healing rate. Overall, it is anticipated that the Cel/Pec-SPI-P bilayer dressing facilitates wound treatment and can be a promising approach for clinical use.

Mupirocin loaded core-shell pluronic-pectin-keratin nanofibers improve human keratinocytes behavior, angiogenic activity and wound healing

In the current study, a core-shell nanofibrous wound dressing based on Pluronic-F127 (F127) containing 2 wt% mupirocin (Mup) core and pectin (Pec)-keratin (Kr) shell was fabricated through coaxial electrospinning technique, and the blended nanofibers were also fabricated from the same materials. The fiber diameter and specific surface area of the blended nanofibers were about 101.56 nm and 20.16 m2/g, while for core-shell nanofibers they were about 97.32 nm and 25.26 m2/g, respectively. The resultant blended and core-shell nanofibers experienced a degradation of 27.65 % and 32.28 % during 7 days, respectively. The drug release profile of core-shell nanofibers revealed a sustained release of Mup over 7 days (87.66 %), while the blended F127-Pec-Kr-Mup nanofibers had a burst release within the first few hours (89.38 % up to 48 h) and a cumulative release of 91.36 % after 7 days. Due to the controlled release of Mup, the core-shell structure significantly improved the human keratinocytes behavior, angiogenic potential and wound healing in a rat model compared to the blended structure. In conclusion, the F127-Mup/Pec-Kr core-shell nanofibrous wound dressing appears to be a promising candidate for the prevention of infection, and can potentially accelerate the recovery and healing of chronic and ischemic wounds.