Forward Wound Closure with Regenerated Silk Fibroin and Polylysine-Modified Chitosan Composite Bioadhesives as Dressings

Oil-droplet anchors accelerate the gelation of regenerated silk fibroin-based emulsion gels

The oil fraction will affect the aggregation behavior and structural strength of emulsion gels. In this study, the effect of the camellia oil (CO) fraction on the properties of emulsion gels stabilized by regenerated silk fibroin (RSF) was studied. The results showed that CO was essential for gel formation, with oil droplets incorporated into the RSF matrix as anchors to achieve rapid gelation of RSF. The gel hardness significantly increased from 20.03 to 53.35 g as the fraction of CO increased from 5 % to 25 %. The oxidation stability of the emulsion gels was also improved, and the peroxide value (POV) decreased from 2419.3 to 839.9 μmol/kg. As the oil fraction rose from 5 % to 25 %, the percentage of released free fatty acids decreased from 73.24 % to 59.49 % due to forming a more compact gel structure. In addition, the rheological results revealed that all emulsion gels had a shear-thinning behavior and good temperature stability in the range of 5 to 90 °C. This study provided a theoretical basis for preparing RSF-based emulsion gels, helps in the recycling of silk protein resources, and promotes the development of emulsion gel applications in the food industry.

Using polycaprolactone and sodium alginate to prepare self-pumping/super-absorbent/transportable drug dressings for stage 3-4 pressure ulcer treatment

Pressure ulcer dressings with different functions can enhance wound healing ability to varying degrees; however, pressure ulcer dressings that integrate various functions and break the resistance of bacteria to traditional antibiotics have not been widely studied. We proposed a self-pumping/super-absorbent/transportable drug dressing (PLD-SLD), polycaprolactone (PCL)/sodium alginate (SA) was used to load platelet-derived growth factor (PDGF) and lidocaine hydrochloride (LID) by Janus electrospinning and self-assembly technology, and Ɛ-polylysine was used as a biological bacteriostatic agent to prepare a multi-layer dressing. SEM showed that the dressing had a fluffy structure. The dressing can pump the exudate to the SA layer away from the skin. The swelling ratio reached 1378.667 ± 44.752 %. Coagulate blood in 5 min. On the 8th day, the unclosed area rate of the PLD-SLD dressing group was 16.112 ± 0.088 % lower than that of the model group. Importantly, the dressing can induce the expression of CD31, VEGF, α-SMA, and reduce the expression of CD68, thereby giving priority to wound healing. There was no scar formation after healing. In this study, a new dressing preparation method was proposed for the problems of exudate management, infection control, pain relief and healing promotion of stage 3-4 pressure ulcer healing.

Release of exosomes from injectable silk fibroin and alginate composite hydrogel for treatment of myocardial infarction

Myocardial infarction (MI) is considered as a significant cause of death globally. Exosomes (EXOs) are essential for intercellular communication and pathophysiology of several cardiovascular diseases. Nevertheless, the short half-life and rapid clearance of EXOs leads to a lack of therapeutic doses delivered to the lesioned area. Therefore, an injectable silk fibroin and alginate (SF/Alg) composite hydrogel was developed to bind folate receptor-targeted EXOs (FA-EXOs) derived from H9C2 cells for the therapy of myocardial injury following myocardial infarction-ischemia/reperfusion (MI-I/R). The resulting composite exhibits a variety of properties, including adjustable gelation kinetics, shear-thinning injectability, soft and dynamic stability that adapts to the heartbeat, and outstanding cytocompatibility. After injected into the damaged rat heart, administration of SF/Alg + FA-EXOs significantly enhanced cardiac function as demonstrated by improved ejection fraction, fractional shortening and decreased fibrosis area. The results of real-time PCR and immunofluorescence staining show a remarkable up-regulation in the expression of proteins (CD31) and genes (VWF and Serca2a) related to the heart. Conversely, expression of fibrosis-related genes (TGF-β1) decreased significantly. Therefore, the obtained SF/Alg + FA-EXOs system remarkably enhanced the intercellular interactions, promoted cell proliferation and angiogenesis, and achieved an outstanding therapeutic effect on MI.

Antibacterial polylysine-containing hydrogels for hemostatic and wound healing applications: preparation methods, current advances and future perspectives

The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.

A novel injectable thermo/photo dual-crosslinking hydrogel based on modified chitosan for fast sealing open globe injury

Open globe injuries (OGIs) demand immediate attention to prevent further complications and improve vision prognosis. Herein, we developed a thermo/photo dual-crosslinking injectable hydrogel, HBC_m_Arg, for rapidly sealing OGIs in emergency ophthalmic cases. HBC_m_Arg was prepared with arginine and methacrylic anhydride modified hydroxybutyl chitosan (HBC). HBC_m_Arg was initially in liquid form at 25 °C, enabling easy injection at the injury site. After reaching the ocular surface temperature, it underwent reversible heat-induced gelation to achieve in situ transformation. Further, HBC_m_Arg was capable of rapid photocrosslinking under UV light, forming a dual network structure to bolster mechanical strength, thereby facilitating effective OGI closure. Biocompatibility assessments, including in vitro studies with three ocular cell types and in vivo experiments on rabbit eyes, confirmed the safety profile of HBC_m_Arg. Ex vivo and in vivo burst pressure tests demonstrated the hydrogel's ability to promptly restore intraocular pressure and withstand elevated pressures, underscoring its potential for OGI stabilization. Additionally, the suitable degradation of HBC_m_Arg within ocular tissues, coupled with its stability in ex vivo assessments, presented a delicate balance between stability and biodegradability. In conclusion, HBC_m_Arg holds promise for improving emergency ophthalmic care by providing a rapid, effective, and safe way to seal OGIs in critical situations.

Silk fibroin-based dressings with antibacterial and anti-inflammatory properties

Silk fibroin is a fibrillar protein obtained from arthropods such as mulberry and non-mulberry silkworms. Silk fibroin has been used as a dressing in wound treatment for its physical, chemical, mechanical, and biological properties. This systematic review analyzed studies from PubMed, Web of Science, and Scopus databases to identify the molecules preferred for functionalizing silk fibroin-based dressings and to describe their mechanisms of exhibiting anti-inflammatory and antibacterial properties. The analysis of the selected articles allowed us to classify the dressings into different conformations, such as membranes, films, hydrogels, sponges, and bioadhesives. The incorporation of various molecules, including antibiotics, natural products, peptides, nanocomposites, nanoparticles, secondary metabolites, growth factors, and cytokines, has allowed the development of dressings that promote wound healing with antibacterial and immunomodulatory properties. In addition, silk fibroin-based dressings have been established to have the potential to regenerate wounds such as venous ulcers, arterial ulcers, diabetic foot, third-degree burns, and neoplastic ulcers. Evaluation of the efficacy of silk fibroin-based dressings in tissue engineering is an area of great activity that has shown significant advances in recent years.

Physico‐chemical properties and in‐vitro biocompatibility of thermo‐sensitive hydrogel developed with enhanced antimicrobial activity for soft tissue engineering

Smart materials such as thermo‐sensitive in situ forming hydrogels can be effective agents in drug delivery and tissue regeneration with minimal invasion. Injection method would avoid complex surgical procedures facilitating rapid recovery process. In this research, we report the fabrication of an easy, reproducible thermo‐sensitive hydrogel constituting of chitosan (CHI), glycerol phosphate (GP) with variable quantity of ‐poly‐l‐lysine (PS). Fourier‐transform infrared spectra exhibited hydrogel formation where interactions between CHI and GP were seen. The gelation kinetics presented gelation time of 8 min at physiological temperature. The results indicated an increase in degradation rate with the passage of time. Contact angles measurements were employed to observe hydrophilic characteristics which were shown to be favorable. Mechanical strength was determined to be in the range of ~0.1–0.6 MPa for all the hydrogels. Due to intrinsic antibacterial features of CHI and PS, the hydrogels showed potent antibacterial activity against Escherichia coli, Staphylococcus aureus, and Methicillin‐resistant S. aureus (MR‐SA). Interestingly, PS's addition in the hydrogel resulted in potent antibacterial activity against clinically relevant MR‐SA. The hydrogels can hence be delivered to a specific target for localized treatments where the potential of inhibiting multidrug resistant strain is clinically relevant. Biocompatibility of the hydrogels was seen by an overall increase in cell viability of mouse fibroblast cells and scratch assay revealed favorable migration potential. Proangiogenic Vascular endothelial growth factor (VEGF)'s expression showed a gradual increase with increasing concentration of PS, whereas one composition demonstrated a slight increase in the expression of cytosolic prostaglandin E synthase (cPGES) as determined by RT‐PCR. Overall, an increase in PS content of the hydrogels resulted in simultaneously enhanced antibacterial efficiency and marked increase in fibroblast cell viability, hence, reiterating their potential as potent antibacterial agents that can be explored as wound healing agents. In conclusion, novel antibacterial thermo‐sensitive hydrogels were synthesized with a potential of regulating proangiogenic and tissue regeneration factors that highlight their role as wound healing agents.

Preparation and Properties of Antibacterial Silk Fibroin Scaffolds

The development of a wound dressing with both antibacterial and healing-guiding functions is a major concern in the treatment of open and infected wounds. In this study, poly(hexamethylene biguanide) hydrochloride (PHMB) was loaded into a 3D silk fibroin (SF) scaffold based on electrostatic interactions between PHMB and SF, and PHMB/SF hybrid scaffolds were prepared via freeze-drying. The effects of the PHMB/SF ratio on the antibacterial activity and cytocompatibility of the hybrid scaffold were investigated. The results of an agar disc diffusion test and a bacteriostasis rate examination showed that when the mass ratio of PHMB/SF was greater than 1/100, the scaffold exhibited obvious antibacterial activity against E. coli and S. aureus. L-929 cells were encapsulated in the PHMB/SF scaffolds and cultured in vitro. SEM, laser scanning confocal microscopy, and CCK-8 assay results demonstrated that hybrid scaffolds with a PHMB/SF ratio of less than 2/100 significantly promoted cell adhesion, spreading, and proliferation. In conclusion, a hybrid scaffold with a PHMB/SF ratio of approximately 2/100 not only effectively inhibited bacterial reproduction but also showed good cytocompatibility and is expected to be usable as a functional antibacterial dressing for wound repair.

Trimesic acid-functionalized chitosan: A novel and efficient multifunctional organocatalyst for green synthesis of polyhydroquinolines and acridinediones under mild conditions

Trimesic acid-functionalized chitosan (Cs/ECH-TMA) material was prepared through a simple procedure by using inexpensive and commercially available chitosan (Cs), epichlorohydrin (ECH) linker and trimesic acid (TMA). The obtained bio-based Cs/ECH-TMA material was characterized using energy-dispersive X-ray (EDX) and Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The Cs/ECH-TMA material was successfully used, as a multifunctional heterogeneous and sustainable catalyst, for efficient and expeditious synthesis of medicinally important polyhydroquinoline (PHQ) and polyhydroacridinedione (PHA) scaffolds through the Hantzsch condensation in a one-pot reaction. Indeed, the heterogeneous Cs/ECH-TMA material can be considered as a synergistic multifunctional organocatalyst due to the presence of a large number of acidic active sites in its structure as well as hydrophilicity. Both PHQs and PHAs were synthesized in the presence of biodegradable heterogeneous Cs/ECH-TMA catalytic system from their corresponding substrates in EtOH under reflux conditions and high to quantitative yields. The Cs/ECH-TMA catalyst is recyclable and can be reused at least four times without significant loss of its catalytic activity.

Recent advances in adhesive materials used in the biomedical field: adhesive properties, mechanism, and applications

Adhesive materials are natural or synthetic polymers with the ability to adhere to the surface of luminal mucus or epithelial cells. They are widely used in the biomedical field due to their unique adhesion, biocompatibility, and excellent surface properties. When used in the human body, they can adhere to an accessible target and remain at the focal site for a longer period, improving the therapeutic effect on local disease. An adhesive material with bacteriostatic properties can play an antibacterial role at the focal site and the adhesive properties of the material can prevent the focal site from being infected by bacteria for a period. In addition, some adhesive materials can promote cell growth and tissue repair. In this review, the properties and mechanism of natural adhesive materials, organic adhesive materials, composite adhesive materials, and underwater adhesive materials have been introduced systematically. The applications of these adhesive materials in drug delivery, antibacterials, tissue repair, and other applications are described in detail. Finally, we have discussed the prospects and challenges of using adhesive materials in the field of biomedicine.

Design strategies for adhesive hydrogels with natural antibacterial agents as wound dressings: Status and trends

The wound healing process is usually susceptible to different bacterial infections due to the complex physiological environment, which significantly impairs wound healing. The topical application of antibiotics is not desirable for wound healing because the excessive use of antibiotics might cause bacteria to develop resistance and even the production of super bacteria, posing significant harm to human well-being. Wound dressings based on adhesive, biocompatible, and multi-functional hydrogels with natural antibacterial agents have been widely recognized as effective wound treatments. Hydrogels, which are three-dimensional (3D) polymer networks cross-linked through physical interactions or covalent bonds, are promising for topical antibacterial applications because of their excellent adhesion, antibacterial properties, and biocompatibility. To further improve the healing performance of hydrogels, various modification methods have been developed with superior biocompatibility, antibacterial activity, mechanical properties, and wound repair capabilities. This review summarizes hundreds of typical studies on various ingredients, preparation methods, antibacterial mechanisms, and internal antibacterial factors to understand adhesive hydrogels with natural antibacterial agents for wound dressings. Additionally, we provide prospects for adhesive and antibacterial hydrogels in biomedical applications and clinical research.

Design of 3D polycaprolactone/ε-polylysine-modified chitosan fibrous scaffolds with incorporation of bioactive factors for accelerating wound healing

Electrospun nanofibrous scaffolds show great application potentials for wound healing owing to their effective simulation of extracellular matrix (ECM). Three-dimensional (3D) nanofibrous dressings exhibit relatively high specific surface areas, better mimicry of native ECM, adjustable hydrophilicity and breathability, good histocompatibility, enhanced wound healing, and reduced inflammation. In the present work, we designed the 3D polycaprolactone/ε-polylysine modified chitosan (PCL/PCS) nanofibrous scaffolds by an electrospinning and gas foaming process. Then, gelatin and heparin (Gel/Hep) were assembled onto the surface of PCL/PCS nanofibers by electrostatic adsorption, and vascular endothelial growth factors (VEGFs) were also synchronously incorporated into Gel/Hep layer to form a multifunctional 3D nanofibrous scaffold (PCL/PCS@Gel/Hep+VEGF) for accelerating wound healing. The as-fabricated 3D PCL/PCS@GEL/Hep+VEGF nanofibrous scaffold showed excellent antibacterial ability, hemocompatibility and biocompatibility in vitro and wound healing ability in vivo. Immunological analysis showed that the as-fabricated nanofibrous scaffold inhibited inflammation at the wound sites while promoting angiogenesis during the wound healing process. STATEMENT OF SIGNIFICANCE: The electrospun 3D fibrous scaffolds using polycaprolactone/ε-polylysine modified chitosan (PCL/PCS) have been fabricated as backbone for mimicking the extracellular matrix (ECM). Gelatin and heparin (Gel/Hep) were wrapped onto the surface of PCL/PCS fibers by electrostatic adsorption and vascular endothelial growth factors (VEGFs) were also synchronously incorporated into surface Gel/Hep layer to form multifunctional 3D fibrous scaffolds. The as-fabricated multifunctional 3D fibrous scaffolds with good antibacterial ability and biocompatibility have been used as dressings for accelerating wound healing by inhibiting inflammation at the wound sites while promoting angiogenesis during the wound healing process.

Fabrication of Curcumin-Loaded Silk Fibroin and Polyvinyl Alcohol Composite Hydrogel Films for Skin Wound Healing

Skin regeneration of full-thickness wounds remains a challenge, requiring a well-regulated interplay of cell-cell and cell-matrix signaling. Herein, the composite hydrogel films composed of silk fibroin (SF) and polyvinyl alcohol (PVA) as scaffolds loaded with curcumin nanoparticles (Cur NPs) were developed for skin wound healing. The structure and physicochemical properties of hydrogel films were first evaluated by scanning electron microscopy (SEM), water contact angle, and chemical and mechanical measurements. In addition, the as-fabricated composite hydrogel films have a unique 3D structure and excellent biocompatibility that facilitates the adhesion and growth of cells. Antimicrobial tests in vitro showed that they could inhibit the growth of bacteria due to the incorporation of Cur NPs into composite hydrogel films. The efficacy of the curcumin-loaded SF/PVA composite hydrogel films for skin wound healing was investigated on the skin defect model in vivo. Immunological analysis showed that the as-fabricated Cur NP-loaded SF/PVA composite hydrogel films inhibited inflammation at the wound sites, while promoting angiogenesis during the wound healing process.

Synergetic integrations of bone marrow stem cells and transforming growth factor-β1 loaded chitosan nanoparticles blended silk fibroin injectable hydrogel to enhance repair and regeneration potential in articular cartilage tissue

The cartilage repair and regeneration show inadequate self-healing capability and have some complications, which are inordinate challenges in clinical therapy. Biopolymeric injectable hydrogels, a prominent type of cell-carrier as well tissue engineering scaffolding materials, establish promising therapeutic potential of stem cell-based cartilage-regeneration treatment. In addition, injectable scaffolding biomaterial should have rapid gelation properties with adequate rheological and mechanical properties. In the present investigation, we developed and fabricated the macromolecular silk fibroin blended with polylysine modified chitosan polymer (SF/PCS) using thermal-sensitive glycerophosphate (GP), which contains effective gelation ability, morphology, porosity and also has enhanced mechanical properties to induce physical applicability, cell proliferation and nutrient exchange in the cell-based treatment. The developed and optimised injectable hydrogel group has good biocompatibility with human fibroblast (L929) cells and bone marrow-derived mesenchymal stem cells (BMSCs). Additionally, it was found that SF/PCS hydrogel group could sustainably release TGF-β1 and efficiently regulate cartilage-specific and inflammatory-related gene expressions. Finally, the cartilage-regeneration potential of the hydrogel groups embedded with and without BMSCs were evaluated in SD rat models under histopathological analysis, which showed promising cartilage repair. Overall, we conclude that the TGF-β1-SF/PCS injectable hydrogel demonstrates enhanced in vitro and in vivo tissue regeneration properties, which lead to efficacious therapeutic potential in cartilage regeneration.

Construction of chitosan-based asymmetric antioxidant and anti-inflammatory repair film for acceleration of wound healing

Oxidative stress damage caused by free radicals around the moist microenvironment of wound has been a clinical challenge in skin tissue healing. Here, a novel chitosan-based bioinspired asymmetric wound repair composite (BAWRC) film was designed by facilitated endogenous tissue engineering strategy through layer-by-layer self-assembly technology for accelerated wound healing. The asymmetric characteristics were skillfully reflected by two different functional layers: hydrophilic chitosan (CS)/silk fibroin (SF) repair layer, and a hydrophobic bacteriostatic tea tree oil (TTO) layer with a rough surface. Simultaneously, sodium ascorbate (SA)-entrapped poly (lactic-co-glycolic acid) (PLGA) microspheres are distributed homogeneously in the hydrophilic layer to induce antioxidant response for skin repair. The distinctive asymmetric structure of BAWRC film endows it with synergistic effects, i.e., protects against the risk of infection from the external environment and facilitates deep skin wound healing. Results show that the minimum inhibition and bactericidal concentration of the BAWRC film were 1.25 and 6.25 mg/mL, respectively, demonstrating good antibacterial properties. The content of biofilm formation was significantly reduced when the concentration of TTO exceeds 5 mg/mL, indicating TTO shows a positive effect on bacteriostasis. In addition, the DPPH rates of BAWRC film were up to 64.7 % after incubation for 12 h, which was ascribed to that the release of SA and TTO as a natural product could accelerate free radical scavenging. The BAWRC film exhibited excellent biocompatibility, and good antibacterial capacity, enhancing adhesion and proliferation of the NIH3T3 cell in vitro, further facilitating the healing of a rat full-thickness skin wounds model. Herein, this versatile asymmetric film possesses great potential for clinical management of wound healing and related soft tissue regeneration.

Breathable, Moisturizing, Anti-Oxidation SSD-PG-PVA/KGM Fibrous Membranes for Accelerating Diabetic Wound Tissue Regeneration

Diabetic wound tissue repair and regeneration is a multi-step process that includes cell proliferation and migration, gas and moisture management, and inflammatory responses. However, current wound dressing designs lack consideration of the wound microenvironment of diabetic patients, making diabetic wound tissue repair a challenge. Here, we report a wound dressing (SSD-PG-PVA/KGM) with a porous structure and anti-oxidant properties for promoting diabetic wound tissue repair. First, the porous structure created by electrospinning technology encourages cell proliferation and migration in the wound while also providing breathability and moisture retention. Second, adding natural polyphenols (PG) and saikosaponins (SSDs) to the wound reduced reactive oxygen species levels and oxide stress. In vitro cell experiments showed that SSD-PG-PVA/KGM had good biocompatibility. Due to the biocompatibility, anti-oxidation ability, breathability, and moisturizing, SSD-PG-PVA/KGM could effectively promote the repair of diabetic wound tissue (the wound closure rate was 95.6% at 14 days).

A Review on Antibacterial Silk Fibroin-based Biomaterials: Current State and Prospects

Bacterial contamination of biomaterials is a common problem and a serious threat to human health worldwide. Therefore, the development of multifunctional biomaterials that possess antibacterial properties and can resist infection is a continual goal for biomedical applications. Silk fibroin (SF), approved by U.S. Food and Drug Administration (FDA) as a biomaterial, is one of the most widely studied natural polymers for biomedical applications due to its unique mechanical properties, biocompatibility, tunable biodegradation, and versatile material formats. In the last decade, many methods have been employed for the development of antibacterial SF-based biomaterials (SFBs) such as physical loading or chemical functionalization of SFBs with different antibacterial agents and bio-inspired surface modifications. In this review, we first describe the current understanding of the composition and structure-properties relationship of SF as a leading-edge biomaterial. Then we demonstrate the different antibacterial agents and methods implemented for the development of bactericidal SFBs, their mechanisms of action, and different applications. We briefly address their fabrication methods, advantages, and limitations, and finally discuss the emerging technologies and future trends in this research area.

Bioactive Silk Fibroin-Based Hybrid Biomaterials for Musculoskeletal Engineering: Recent Progress and Perspectives

Musculoskeletal engineering has been considered as a promising approach to customize regenerated tissue (such as bone, cartilage, tendon, and ligament) via a self-healing performance. Recent advances have demonstrated the great potential of bioactive materials for regenerative medicine. Silk fibroin (SF), a natural polymer, is regarded as a remarkable bioactive material for musculoskeletal engineering thanks to its biocompatibility, biodegradability, and tunability. To improve tissue-engineering performance, silk fibroin is hybridized with other biomaterials to form silk-fibroin-based hybrid biomaterials, which achieve superior mechanical and biological performance. Herein, we summarize the recent development of silk-based hybrid biomaterials in musculoskeletal tissue with reasonable generalization and classification, mainly including silk fibroin-based inorganic and organic hybrid biomaterials. The applied inorganics are composed of calcium phosphate, graphene oxide, titanium dioxide, silica, and bioactive glass, while the polymers include polycaprolactone, collagen (or gelatin), chitosan, cellulose, and alginate. This article mainly focuses on the physical and biological performances both in vitro and in vivo study of several common silk-based hybrid biomaterials in musculoskeletal engineering. The timely summary and highlight of silk-fibroin-based hybrid biomaterials will provide a research perspective to promote the further improvement and development of silk fibroin hybrid biomaterials for improved musculoskeletal engineering.

Effect of the Degree of Acetylation of Chitin Nonwoven Fabrics for Promoting Wound Healing

Chitin and chitosan have been extensively used as wound dressings because of their special functions to promote wound healing. However, there was little focus on the effects of the degree of acetylation (DA) on wound healing. In this work, the regenerated chitin nonwoven fabrics with DA values of 90, 71, 60, and 42% were prepared, and the morphology and physical performances of the fabrics were characterized. Moreover, the effects of DA of the chitin nonwoven fabrics on wound recovery were studied with a full-thickness skin defect model in rats. In vitro experiments indicated that the chitin nonwoven fabrics exhibited good biocompatibility and blood compatibility and a low blood-clotting index (BCI). In vivo experiments revealed that the chitin nonwoven fabrics could accelerate wound healing more effectively than gauze by promoting re-epithelialization and collagen deposition as well as by stimulating neovascularization. The results of the wound healing process showed that DA of the chitin nonwoven fabrics had a profound effect on promoting wound healing. Notably, the regenerated chitin nonwoven fabrics with 71% DA significantly improved the wound healing compared to the commercial wound dressing Algoplaque film. Therefore, the regenerated chitin nonwoven fabrics are promising candidates for wound healing.

Electrospun Scaffold of Collagen and Polycaprolactone Containing ZnO Quantum Dots for Skin Wound Regeneration

Nanofibers (NFs) have been widely used in tissue engineering such as wound healing. In this work, the antibacterial ZnO quantum dots (ZnO QDs) have been incorporated into the biocompatible poly (ε-caprolactone)/collagen (PCL/Col) fibrous scaffolds for wound healing. The as-fabricated PCL-Col/ZnO fibrous scaffolds exhibited good swelling, antibacterial activity, and biodegradation behaviors, which were beneficial for the applications as a wound dressing. Moreover, the PCL-Col/ZnO fibrous scaffolds showed excellent cytocompatibility for promoting cell proliferation. The resultant PCL-Col/ZnO fibrous scaffolds containing vascular endothelial growth factor (VEGF) also exhibited promoted wound-healing effect through promoting expression of transforming growth factor-β (TGF-β) and the vascular factor (CD31) in tissues in the early stages of wound healing. This new electrospun fibrous scaffolds with wound-healing promotion and antibacterial property should be convenient for treating wound healing.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42235-021-00115-7.