Keratin- and VEGF-Incorporated Honey-Based Sponge-Nanofiber Dressing: An Ideal Construct for Wound Healing

Evaluation of the management of rotator cuff injuries utilising superparamagnetic iron oxide tracking stem cells

BACKGROUND

The ultrastructure of the tendon-bone interface (TBI) is inherently complex. After arthroscopic reconstruction, it is often replaced by disorganized scar tissue, which increases the risk of re-tearing.Stem cell therapies offer a promising approach to regenerate the original tissue structure and enhance the healing environment. The effectiveness of these therapies depends on understanding the localization, proliferation, and overall behavior of the implanted stem cells. This study aimed to track the distribution of stem cells in a rat model of rotator cuff injury using Magnetic Resonance Imaging (MRI) and superparamagnetic iron oxide nanoparticles (SPIO) and to evaluate the mechanisms and therapeutic effects of stem cell therapy.

METHODS

Adipose-derived mesenchymal stem cells (ADSCs) were isolated and expanded, then labeled with SPIO at an optimized concentration. The visibility of these labeled cells was assessed via MRI, along with evaluations of their viability, potential toxicity, and migration capacity in vitro.For the in vivo study, rats with rotator cuff tears were divided into two groups: a control group that received a PBS injection, and a treatment group that received SPIO-labeled ADSCs (designated as S-A). MRI scans were conducted at 1, 2, and 4 weeks post-surgery, followed by histological analysis after the rats were euthanized. At 8 weeks post-surgery, rats were sacrificed, and their shoulder joints were analyzed biomechanically and histologically to assess the overall treatment efficacy.

RESULTS

SPIO nanoparticles were successfully incorporated into ADSCs, and MRI imaging demonstrated that these SPIO-labeled cells significantly enhanced MRI contrast without affecting cell viability, proliferation, or migration ability. Both MRI and histological analyses confirmed that the implanted stem cells survived and remained localized for at least two weeks. Further histological and biomechanical evaluations indicated that the stem cells facilitated the repair of the TBI. This repair process appeared to be mediated by an increase in M2 macrophage activity within the injured tissue, promoting improved local healing conditions.

CONCLUSION

This study confirms that labeling ADSCs with SPIO nanoparticles is an effective method for tracking these cells in vivo using MRI, providing a non-invasive approach to monitor the repair of injured TBI. Moreover, the localized survival of transplanted stem cells supports their role in enhancing TBI repair by modulating the local inflammatory response.

Targeting m6A demethylase FTO to heal diabetic wounds with ROS-scavenging nanocolloidal hydrogels

Chronic diabetic wounds are a prevalent and severe complication of diabetes, contributing to higher rates of limb amputations and mortality. N6-methyladenosine (m6A) is a common RNA modification that has been shown to regulate tissue repair and regeneration. However, whether targeting m6A could effectively improve chronic diabetic wound healing remains largely unknown. Here, we found a significant reduction in mRNA m6A methylation levels within human diabetic foot ulcers, and the expression level of fat mass and obesity-associated protein (FTO) was significantly increased. We identified that m6A modifies the RNA of matrix Metalloproteinase 9 (MMP9), a key factor in diabetic wound healing, to regulate its expression. Importantly, we developed a ROS-scavenging nanocolloidal hydrogel loaded with an FTO inhibitor to increase the m6A level of MMP9 RNA in wounds. The hydrogel can effectively accelerate wound healing and skin appendage regeneration in streptozotocin-induced type I diabetic rats at day 14 (approximately 98 % compared to 76.98 % in the control group) and type II diabetic db/db mice at day 20 (approximately 93 % compared to 60 % in the control group). Overall, our findings indicate that targeting m6A with ROS-scavenging hydrogel loaded with FTO inhibitor may be an effective therapeutic strategy for diabetic wound healing.

Incorporation of forsterite nanoparticles in a 3D printed polylactic acid/polyvinylpyrrolidone scaffold for bone tissue regeneration applications

Three-dimensional (3D) printing has facilitated the fabrication of customized scaffolds for the repair of complex bone defects. In this study, 3D-printed scaffolds composed of a mixture of polylactic acid-polyvinylpyrrolidone (PLA-PVP) incorporating different amounts of forsterite (F; Mg2SiO4) nanoparticles were fabricated using fused deposition modeling (FDM) technique. The incorporation of PVP and F nanoparticles into the PLA scaffold significantly decreased the water drop contact angle. The mechanical properties of the PLA-PVP scaffold were enhanced with the addition of 10 % F nanoparticles, as the compressive yield strength increased from 10.8 to 16.0 MPa and the elastic modulus from 83.52 to 108.41 MPa. However, the addition of F nanoparticles increased the degradation rate of the PLA-PVP scaffold over 8 weeks. Importantly, the addition of 10 % F nanoparticles into the PLA-PVP scaffold improved bioactivity and formation of apatite deposits on the scaffold after 4 weeks of immersion in simulated body fluid. Moreover, the PLA-PVP/10F scaffold showed strong MG63 cell adhesion and proliferation, as well as promoting osteogenic differentiation of rat bone marrow mesenchymal stem cells. At last, these findings suggest the PLA-PVP/10F scaffold is a promising candidate for application in bone defect repair.

Biomimetic skin regeneration using a dual-layer scaffold/hydrogel: Polycaprolactone-gelatin electrospun scaffold incorporated with bromelain-silver nanoparticles and alginate hydrogel enriched with selenium-doped bioglass

Skin regeneration remains a critical area of research due to the skin's pivotal roles in protection, sensation, and thermoregulation. This study introduces a novel biomimetic approach for enhancing skin regeneration by integrating a double-layered Polycaprolactone (PCL)-gelatin (Gel) electrospun scaffold containing Bromelain‑silver nanoparticles (Bro-AgNPs) with an alginate (Alg) hydrogel incorporating bioglass particles (BGPs) and selenium-doped BGPs (SeBGPs) as well as the injection of mesenchymal stem cells (MSCs) into wound edges. The Bro-AgNPs, incorporated into the scaffold, exhibited potent antimicrobial activity. The BGPs and SeBGPs promoted cell viability, achieving most cell proliferation at 20 % concentration in vitro. Physical characterization revealed that adding Bro-AgNPs increased the yield strength of the PCL-Gel-Bro-AgNPs scaffold to 1.59 ± 0.20 MPa compared to 1.30 ± 0.12 MPa for the PCL-Gel scaffold while maintaining comparable stiffness. Furthermore, the incorporation of BGPs and SeBGPs into Alg hydrogels reduced swelling ratios (after 24 h) to 162.1 ± 13.47 and 158.7 ± 15.25, and porosity to 72.82 ± 2.21 and 71.52 ± 2.76, respectively, compared to 208.8 ± 12.38 and 78.05 ± 2.60 % for Alg hydrogel. In vivo studies demonstrated that the SeBGPs + mesenchymal stem cells (MSCs) group achieved the highest wound closure at all experimental days. Histological evaluations on day 21 confirmed robust tissue regeneration, including thick epithelialization and well-organized collagen fibers, without inflammation. These findings demonstrate the composite's potential to support cellular activity, provide antimicrobial protection, and enhance mechanical properties, offering promise for clinical applications in skin tissue engineering.

In-vitro and in-vivo studies of Tridax procumbens leaf extract incorporated bilayer polycaprolactone/polyvinyl alcohol-chitosan electrospun nanofiber for wound dressing application

This study was an attempt to fabricate an antibacterial wound dressing, which was a bilayered polycaprolactone / polyvinyl alcohol-chitosan (PCL/PVA-CS) nanofibrous membrane. Entrapping ethanolic leaf extract of Tridax procumbens L. (PCL/PVA-CS/Tp). The membrane was prepared using the electrospinning technique to obtain beadless uniform nanofibers. The extract was then infused into the membrane by spraying and exposing to high temperature. in vitro antibacterial activity and cell viability of the membranes were performed. An optimized concentration of 800 μg. mL-1 of Tp extract in PCL/PVA-CS/Tp evinced better antibacterial effect on E. coli than S. aureus and also showed rapid wound closure with a positive impact on the viability of L929 cell line. The tissue regeneration efficacy of PCL/PVA-CS/Tp was validated by the experiments on mice models with subcutaneous wounds created using biopsy punch and laser radiation causing burns. Furthermore, in vivo assessments illustrated that the biopsy punch wounds healed more rapidly than laser burn though healing was significant in both. The healing processes such as anti-inflammation and re-epithelialization were observed through histological study. The upregulation of proteins namely VEGF and CD31 along with a decrease in protein levels of Wnt and TGF-β indicated significant wound healing. In conclusion, the bilayered membrane infused with plant extract could be considered a potential material for wound dressing.

Chitosan-based injectable porous microcarriers with enhanced adipogenic differentiation and angiogenesis for subcutaneous adipose tissue regeneration

Chitosan is a promising biomaterial for tissue engineering, but its functionality is limited by a lack of bioactive sites. This study develops chitosan/amniotic membrane microcarriers to enhance vascularization and tissue regeneration for subcutaneous adipose tissue. The incorporation of decellularized amniotic membrane enhances the bioactivities of chitosan in promoting cell differentiation and angiogenesis. Optimized preparation yielded porous microcarriers with a particle size of 261.2 ± 28 μm and an average pore size of 19.0 ± 4 μm. In vitro degradation analysis showed accelerated degradation with higher amniotic membrane content. Cytocompatibility and adipogenic capacity assessments indicated that the microcarriers supported cell adhesion and proliferation over 7 days, with amniotic membrane facilitating adipogenic differentiation of adipose-derived stem cells. When injected subcutaneously into nude mice, these microcarriers formed neoplastic adipose tissues, which were harvested 8 weeks later. Fluorescence staining, oil-red O staining and CD31 labeling demonstrated that amniotic membrane incorporation significantly enhanced in vivo adipose tissue formation and angiogenesis.

Antibacterial and osteogenic properties of chitosan-polyethylene glycol nanofibre-coated 3D printed scaffold with vancomycin and insulin-like growth factor-1 release for bone repair

3D printing, as a layer-by-layer manufacturing technique, enables the customization of tissue engineering scaffolds. Surface modification of biomaterials is a beneficial approach to enhance the interaction with living cells and tissues. In this research, a polylactic acid/polyethylene glycol scaffold containing 30 % bredigite nanoparticles (PLA/PEG/B) was fabricated utilizing fused deposition modeling (FDM) 3D printing. To modify the surface properties and facilitate the loading and release of therapeutics, the scaffold was coated with chitosan-polyethylene glycol (CS-PEG) nanofibers incorporating vancomycin (V) and insulin-like growth factor-1 (IGF1). The characterization was conducted using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the release of V (93.43 %) and IGF1 (95.86 %) from the fabricated scaffolds persisted for 28 days in a phosphate-buffered saline (PBS) solution. The release of V resulted in antibacterial activity against Staphylococcus aureus (S. aureus), forming an inhibition zone of 21.16 mm. Additionally, it was demonstrated that the release of IGF1 could counteract the adverse effect of V release on cell behavior, and enhance the adhesion and proliferation of MG63 cells. Preclinical in vivo studies conducted on a rat calvarial defect model validated that the bone repair was fully completed in the group treated with the fabricated scaffold within 8 weeks. Consequently, the scaffold designed in this study can serve as a versatile scaffold for achieving perfect repair of craniofacial defects.

Enhanced wound healing with a bilayered multifunctional quaternized chitosan-dextran-curcumin construct

This study introduces a novel bilayer wound dressing that integrates a quaternized chitosan-polyacrylic acid (QCs-PAA) sponge as the top layer with electrospun nanofibers containing curcumin as the bottom layer. For the first time, QCs and PAA were combined in an 80:20 ratio through freeze-drying to form a porous sponge layer with ideal structural properties, including 83 ± 6 % porosity and pore diameters of 290 ± 12.5 μm. For the bottom layer, five groups of nanofibers containing PAA, dextran, and curcumin were electrospun onto the porous sponge. All wound dressings were non-toxic and exhibited exceptional antibacterial activity against S. aureus and E. coli. All groups, particularly the QP/PD0.25Cur bilayer dressing, showed significant HaCaT cell adhesion. Angiogenesis assays confirmed a remarkable increase in blood vessel number and thickness in samples containing 0.25 w/w% curcumin, with vascular density increasing from 0.32 in the single-layer sponge to 0.54 in the QP/PD0.25Cur sample, representing a 68 % enhancement. In vivo studies demonstrated that within 14 days, wound healing was accelerated with the QP/PD0.25Cur bilayer dressing, achieving 96 % closure compared to other groups. The findings revealed that all fabricated bilayer sponge-nanofiber wound dressings, particularly the 0.25 w/w% curcumin sample, can be a suitable candidate for wound management.

Vanillin and IGF1-loaded dual-layer multifunctional wound dressing with micro-nanofibrous structure for full-thickness wound healing acceleration

Multifunctional dual-layer wound dressings hold significant promise for comprehensive full-thickness wound management by closely mimicking the native skin structure and features. Herein, we employed an innovative approach utilizing electrospinning techniques to develop a dual-layer dressing comprising a microfibrous Ecoflex®-Vanillin (Ex-Vnil) top layer (TL) and a nanofibrous Soluplus®-Insulin-like growth factor-1 (Sol-IGF1) bottom layer (BL). The tensile properties of dual-layer wound dressings were within the standard range for use in skin tissue regeneration. The TL exhibited hydrophobic properties with a contact angle value of 92.4° and significant antibacterial activity, mimicking the epidermis of the skin, thereby preventing fluid and bacterial penetration. Moreover, the dual-layer wound dressing demonstrated standard water vapour transmission rate, with 91.2 % release of IGF1 and 66.8 % release of Vnil within 5 days. Notably, the fabricated dual-layer dressing promoted cell behaviour and exhibited a significant angiogenesis effect and accelerated healing of full-thickness wound, achieving 96.4 % closure after 14 days, attributed to reduced inflammation, early blood vessel formation, and enhanced collagen density. Our findings underscore the potential of the fabricated dual-layer dressing as an innovative solution in full-thickness wound care.

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.

Multifunctional carboxymethyl chitosan-based sponges loaded with epigallocatechin-3-gallate for accelerating wound healing in diabetic rats with full-thickness burns

Full-thickness burn wounds in diabetes often present significant challenges in terms of timely progression of healing and even mortality. Multifunctional dressings that possess strong absorptivity and mechanical property while effectively regulating inflammation and promoting angiogenesis is therefore crucial. We have developed a novel sponge (CCGE) comprising carboxymethyl chitosan, gelatin, and glycerin for the purpose of promoting accelerated healing of scald wounds in diabetic rats. This sponge is loaded with epigallocatechin-3-gallate, which possesses antioxidant and anti-inflammatory properties. The incorporation of the crosslinker BDDE reinforces its mechanical characteristics by augmenting the interplay between the sponge structure through hydrogen bonding and covalent bonding. Moreover, the crosslinked sponges provide a highly absorptive layer, carboxymethyl chitosan show good biocompatibility and angiogenic effects, and the gelatin provide matrix metalloproteinases-9 targeting. The CCGE sponges exhibit high biocompatibility, facilitate fibroblast migration, and promote tube formation. The application of the CCGE sponges significantly accelerates wound healing of full-thickness scald wounds in diabetic rats, exhibits enhanced collagen synthesis, reduced levels of pro-inflammatory cytokines, and increased blood vessel formation within the wounded area. In summary, this study presents a multifunctional composite CCGE sponge dressing that effectively modulates ROS, inflammation, and angiogenesis to facilitate comprehensive burn wound tissue repair in diabetes.

Multitasking Asynchronous Collaborative Nanosystem for Diabetic Wound Healing Based on Hypoglycemic, Antimicrobial, and Angiogenesis-Promoting Effects

A diabetic foot ulcer (DFU) is a common and serious complication of diabetes. This complication can result in amputation and death because of the several challenges associated with wound healing that can be attributed to the complex wound microenvironment, including biofilm infection, hyperglycemia, and diabetic angiopathy. Existing investigations on the wound-healing rate consider only one or two pathogenic factors, and therefore, despite the extensive research on these pathological microenvironments, there is an urgent need to optimize the wound-healing rate in patients with diabetic foot ulcers. To this end, a multitasking asynchronous collaborative nanosystem is designed in this study. The designed nanosystem can efficiently clear biofilm infections using optimized photodynamic therapy based on a poly photosensitizer ionic liquid (i.e., Ce6IL), reduce local blood glucose concentration using glucose oxidase, and reconstruct blood vessels by stimulating endothelial cell proliferation and migration using nitric oxide. The experimental results indicate that the three-step sequential collaboration strategy for clearing biofilm infections, reducing glucose concentrations, and reconstructing damaged blood vessels can help significantly accelerate wound healing rate in patients with diabetic foot ulcers.

Natural Protein-Based Multifunctional Hydrogel Dressing Formed by Rapid Photocuring and Zinc Ion Coordination to Accelerate Wound Healing

This study explores the use of chicken egg white (EW), a rich source of natural proteins, to address challenges in wound healing management. Herein, a novel Zn2+-infused EW/GelMA (EW/Gel) hybrid hydrogel is developed, featuring an interpenetrating network (IPN) structure, where the first network consists of photo-cross-linked GelMA and the second network consists of Zn2+-infused EW (Zn-EW) through ion-protein binding. By optimizing the design and formulation, the resulting Zn-EW/Gel hydrogel exhibited enhanced mechanical stability and self-adhesive properties. In vitro experiments demonstrated that the combined effects of functional proteins and active ions within the Zn-EW/Gel hydrogel promote fibroblast proliferation and type I collagen expression, modulate the immune microenvironment, and enhance angiogenesis. The hydrogel also demonstrated excellent biocompatibility and bioactivity in vivo, showing strong promise for restoring the physiological properties of the damaged wound tissue.

Vasculo-osteogenic keratin-based nanofibers containing merwinite nanoparticles and sildenafil for bone tissue regeneration

Vascularization of bone tissue constructs plays a pivotal role in facilitating nutrient transport and metabolic waste removal during the processes of osteogenesis and bone regeneration in vivo. In this study, a sildenafil (Sil)-loaded nanofibrous scaffold of keratin/Soluplus/merwinite (KS.Me.Sil) was fabricated through electrospinning and the effectiveness of the scaffold was assessed for bone tissue engineering applications. The KS.Me.Sil nanofibrous scaffold exhibited notably enhanced ultimate tensile strength (3.38 vs 2.61 MPa) and elastic modulus (69.83 vs 46.27 MPa) compared to the KS scaffold. The in vitro release of Ca2+, Si4+ and Mg2+ ions and the release of Sil from the nanofibers as well as biodegradability and bioactivity were evaluated for 14 days. Protein adsorption capability and cytocompatibility of the scaffolds were tested. Alkaline phosphatase activity test, Alizarin red staining and qRT-PCR analysis demonstrated that the KS.Me.Sil nanofibers had the best osteogenic activity among other samples. Also, the results of the chorioallantoic membrane assay showed an almost threefold increase in blood vessel density in the group treated with the KS.Me.Sil nanofibers extract compared to the KS. In conclusion, our findings suggest that the electrospun KS.Me.Sil nanofibrous scaffold offers a robust structure with exceptional osteogenic and angiogenic characteristics, making it a promising candidate for bone tissue engineering applications.

The interplay of skin architecture and cellular dynamics in wound healing: Insights and innovations in care strategies

Wound healing involves complex interactions among skin layers: the epidermis, which epithelializes to cover wounds; the dermis, which supports granulation tissue and collagen production; and the hypodermis, which protects overall skin structure. Key factors include neutrophils, activated by platelet degranulation and cytokines, and fibroblasts, which aid in collagen production during proliferation. The healing process encompasses inflammation, proliferation, and remodeling, with angiogenesis, fibroplasia, and re-epithelialization crucial for wound closure. Angiogenesis is characterized by the creation of collateral veins, the proliferation of endothelial cells, and the recruitment of perivascular cells. Collagen is produced by fibroblasts in granulation tissue, aiding in the contraction of wounds. The immunological response is impacted by T cells and cytokines. External topical application of various formulations and dressings expedites healing and controls microbial contamination. Polymeric materials, both natural and synthetic, and advanced dressings enhance healing by providing biodegradability, biocompatibility, and infection control, thus addressing tissue regeneration challenges. Numerous dressings promote healing, including films, hydrocolloids, hydrogels, foams, alginates, and tissue-engineered substitutes. Wound dressings are treated with growth factors, particularly PDGF, and antibacterial drugs to prevent infection. The challenges of tissue regeneration and infection control are evolving along with the field of wound care.

Natural polymer nanofiber dressings for effective management of chronic diabetic wounds: A comprehensive review

Diabetic wounds present a chronic challenge in effective treatment. Natural polymer nanofiber dressings have emerged as a promising solution due to their impressive biocompatibility, biodegradability, safety, high specific surface area, and resemblance to the extracellular matrix. These qualities make them ideal materials with excellent biological properties and cost-effectiveness. Additionally, they can effectively deliver therapeutic agents, enabling diverse treatment effects. This review offers a comprehensive overview of natural polymer-based nanofibers in diabetic wound dressings. It examines the characteristics and challenges associated with diabetic wounds and the role of natural polymers in facilitating wound healing. The review highlights the preparation, mechanism, and applications of various functional dressings composed of natural polymer nanofibers. Furthermore, it addresses the main challenges and future directions in utilizing natural polymer nanofibers for diabetic wound treatment, providing valuable insights into effective wound management for diabetic patients.

Nanoparticle-Based Therapeutics for Enhanced Burn Wound Healing: A Comprehensive Review

Burn wounds pose intricate clinical challenges due to their severity and high risk of complications, demanding advanced therapeutic strategies beyond conventional treatments. This review discusses the application of nanoparticle-based therapies for optimizing burn wound healing. We explore the critical phases of burn wound healing, including inflammation, proliferation, and remodeling, while summarizing key nanoparticle-based strategies that influence these processes to optimize healing. Various nanoparticles, such as metal-based, polymer-based, and extracellular vesicles, are evaluated for their distinctive properties and mechanisms of action, including antimicrobial, anti-inflammatory, and regenerative effects. Future directions are highlighted, focusing on personalized therapies and the integration of sophisticated drug delivery systems, emphasizing the transformative potential of nanoparticles in enhancing burn wound treatment.

Highly porous sildenafil loaded polylactic acid/polyvinylpyrrolidone based 3D printed scaffold containing forsterite nanoparticles for craniofacial reconstruction

Tissue engineering has emerged as a promising substitute for traditional tissue repair methods. Nowadays, advancements in 3D printing technology have enabled the fabrication of customized scaffolds to support tissue regeneration. In the present study, a polylactic acid-polyvinylpyrrolidone 3D-printed scaffold containing 10 % forsterite was fabricated. Subsequently, lyophilized fucoidan microstructures loaded with sildenafil were filled the channels of this 3D-printed scaffold. The fabricated scaffold loaded with sildenafil was thoroughly characterized, revealing that 97.46 % of the loaded sildenafil was released in a sustained manner over 28 days. Furthermore, the biocompatibility of MG63 was evaluated through cell viability and adhesion tests. The findings indicated a direct and favorable influence on cell behavior. Based on the chicken chorioallantoic membrane assay, the fabricated scaffold significantly increases angiogenesis due to the sustained release of sildenafil. Moreover, in-vivo studies conducted on a rat model demonstrated that the 3D-printed scaffold was able to stimulate and accelerate the repair of calvarial defects within 8 weeks, and the amount of new bone tissue formation was significantly higher than that of other experimental groups. Based on the comprehensive in-vitro and in-vivo assessments, the scaffold with a macro- and microporous structure combined with the ability to release sildenafil is suggested as a potential candidate for repairing bone tissue, especially in the context of skull defects.

A separable double-layer self-pumping dressing containing astragaloside for promoting wound healing

Some skin wounds often have many exudate. Ordinary single layer electrospunning nanofiber wound dressings often don't have enough capacity to absorb them. Therefore, a separable double layer electrospunning nanofiber dressing was developed in this work. The dressing had a separable feature that allowed the upper layer to be separated and removed after it had absorbed a significant amount of wound exudate. This dressing consisted of an upper layer of super hydrophilic sodium polyacrylate nanofibers and a bottom layer of 3D-structure coaxial nanofibers with encapsulated Astragaloside (AS). The results showed that nanofibers had better morphology. The water absorption rate, water vapor transmission rate and free radical scavenging rate of the double-layer dressings were 1461.71 ± 39.72 %, 1193.63 ± 134 g·m-2·day-1, and 63.35 ± 3.65 %, respectively. The double-layer nanofiber dressing achieved 65.69 ± 2.62 % and 75.10 ± 6.26 % inhibition against Staphylococcus aureus and Escherichia coli, respectively. The double-layer dressing had proliferative, migratory, and adhesive effects on L929 fibroblasts. And the double-layer dressing resulted in a 96.78 ± 1.0 % wound healing rate in rats after giving a 14 days treatment. Therefore, the 3D-structure separable double-layer wound dressing designed and prepared in this study was effective in promoting wound healing.

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.

Endogenous electric field coupling Mxene sponge for diabetic wound management: haemostatic, antibacterial, and healing

Improper management of diabetic wound effusion and disruption of the endogenous electric field can lead to passive healing of damaged tissue, affecting the process of tissue cascade repair. This study developed an extracellular matrix sponge scaffold (K1P6@Mxene) by incorporating Mxene into an acellular dermal stroma-hydroxypropyl chitosan interpenetrating network structure. This scaffold is designed to couple with the endogenous electric field and promote precise tissue remodelling in diabetic wounds. The fibrous structure of the sponge closely resembles that of a natural extracellular matrix, providing a conducive microenvironment for cells to adhere grow, and exchange oxygen. Additionally, the inclusion of Mxene enhances antibacterial activity(98.89%) and electrical conductivity within the scaffold. Simultaneously, K1P6@Mxene exhibits excellent water absorption (39 times) and porosity (91%). It actively interacts with the endogenous electric field to guide cell migration and growth on the wound surface upon absorbing wound exudate. In in vivo experiments, the K1P6@Mxene sponge reduced the inflammatory response in diabetic wounds, increased collagen deposition and arrangement, promoted microvascular regeneration, Facilitate expedited re-epithelialization of wounds, minimize scar formation, and accelerate the healing process of diabetic wounds by 7 days. Therefore, this extracellular matrix sponge scaffold, combined with an endogenous electric field, presents an appealing approach for the comprehensive repair of diabetic wounds.

Clinic-oriented injectable smart material for the treatment of diabetic wounds: Coordinating the release of GM-CSF and VEGF

Chronic wounds are often caused by diabetes and present a challenging clinical problem due to vascular problems leading to ischemia. This inhibits proper wound healing by delaying inflammatory responses and angiogenesis. To address this problem, we have developed injectable particle-loaded hydrogels which sequentially release Granulocyte-macrophage- colony-stimulating-factor (GM-CSF) and Vascular endothelial growth factor (VEGF) encapsulated in polycaprolactone-lecithin-geleol mono-diglyceride hybrid particles. GM-CSF promotes inflammation, while VEGF facilitates angiogenesis. The hybrid particles (200-1000 nm) designed within the scope of the study can encapsulate the model proteins Bovine Serum Albumin 65 ± 5 % and Lysozyme 77 ± 10 % and can release stably for 21 days. In vivo tests and histological findings revealed that in the hydrogels containing GM-CSF/VEGF-loaded hybrid particles, wound depth decreased, inflammation phase increased, and fibrotic scar tissue decreased, while mature granulation tissue was formed on day 10. These findings confirm that the hybrid particles first initiate the inflammation phase by delivering GM-CSF, followed by VEGF, increasing the number of vascularization and thus increasing the healing rate of wounds. We emphasize the importance of multi-component and sequential release in wound healing and propose a unifying therapeutic strategy to sequentially deliver ligands targeting wound healing stages, which is very important in the treatment of the diabetic wounds.

A unidirectional water-transport antibacterial bilayer nanofibrous dressing based on chitosan for accelerating wound healing

Excessive accumulation of exudate from wounds often causes infection and hinders skin regeneration. To handle wound exudate quickly and prevent infection, we developed an antibacterial Janus nanofibrous dressing with a unidirectional water-transport function. The dressing consists of a hydrophilic chitosan aerogel (CS-A) as the outer layer and a hydrophobic laurylated chitosan (La-CS) nanofibrous membrane as the inner layer. These dressings achieved excellent liquid absorption performance (2987.8 ± 123.5 %), air and moisture permeability (997.8 ± 23.1 g/m2/day) and mechanical strength (5.1 ± 2.6 MPa). This performance was obtained by adjusting the density of CS-A and the thickness of the La-CS membrane. Moreover, the dressing did not induce significant toxicity to cells and can prevent bacterial aggregation and infection at the wound site. Animal experiments showed that the dressing can shorten the inflammatory phase, enhance blood vessel generation, and accelerate collagen deposition, thus promoting wound healing. Overall, these results suggest that this Janus dressing is a promising material for clinical wound care.

IL-17 in wound repair: bridging acute and chronic responses

Chronic wounds, resulting from persistent inflammation, can trigger a cascade of detrimental effects including exacerbating inflammatory cytokines, compromised blood circulation at the wound site, elevation of white blood cell count, increased reactive oxygen species, and the potential risk of bacterial infection. The interleukin-17 (IL-17) signaling pathway, which plays a crucial role in regulating immune responses, has been identified as a promising target for treating inflammatory skin diseases. This review aims to delve deeper into the potential pathological role and molecular mechanisms of the IL-17 family and its pathways in wound repair. The intricate interactions between IL-17 and other cytokines will be discussed in detail, along with the activation of various signaling pathways, to provide a comprehensive understanding of IL-17's involvement in chronic wound inflammation and repair.

Cell culture on suspended fiber for tissue regeneration: A review

Cell culturing is a cornerstone of tissue engineering, playing a crucial role in tissue regeneration, drug screening, and the study of disease mechanisms. Among various culturing techniques, 3D culture systems, particularly those utilizing suspended fiber scaffolds, offer a more physiologically relevant environment than traditional 2D monolayer cultures. These 3D scaffolds enhance cell growth, differentiation, and proliferation by mimicking the in vivo cellular milieu. This review focuses on the critical role of suspended fiber scaffolds in tissue engineering. We compare the effectiveness of 3D suspended fiber scaffolds with 2D culture systems, discussing their respective benefits and limitations in the context of tissue regeneration. Furthermore, we explore the preparation methods of suspended fiber scaffolds and their potential applications. The review concludes by considering future research directions for optimizing suspended fiber scaffolds to address specific challenges in tissue regeneration, underscoring their significant promise in advancing tissue engineering and regenerative medicine.

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.

Wound Dressing Based on Silver Nanoparticle Embedded Wool Keratin Electrospun Nanofibers Deposited on Cotton Fabric: Preparation, Characterization, Antimicrobial Activity, and Cytocompatibility

Wool keratin (WK) protein is attractive for wound dressing and biomedical applications due to its excellent biodegradability, cytocompatibility, and wound-healing properties. In this work, WK-based wound dressings were prepared by depositing WK/poly(vinyl alcohol) (PVA) and silver nanoparticle (Ag NP)-embedded WK/PVA composite nanofibrous membranes on cotton fabrics by electrospinning. Ag NPs were biosynthesized by reduction and stabilization with sodium alginate. The formed Ag NPs were characterized by ultraviolet-visible and Fourier transform infrared (FTIR) spectroscopy, and their size was determined by transmission electron microscopy and image analysis. The formed Ag NPs were spherical and had an average diameter of 9.95 nm. The produced Ag NP-embedded WK/PVA composite nanofiber-deposited cotton fabric surface was characterized by FTIR and dynamic contact angle measurements, and the nanofiber morphologies were characterized by scanning electron microscopy. The average diameter of the nanofibers formed by 0.1% Ag NP-embedded WK/PVA solution was 146.7 nm. The antibacterial activity of the surface of cotton fabrics coated with electrospun composite nanofibers was evaluated against the two most common wound-causing pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. The cotton fabric coated with 0.1% Ag NP-embedded WK/PVA nanofibers showed very good antibacterial activity against both pathogens, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results showed good cytocompatibility against L-929 mouse fibroblast cells. However, the increase in Ag NP content in the nanofibers to 0.2% negatively affected the cell viability due to the high release rate of Ag ions. The results achieved show that the developed wound dressing has good potential for wound healing applications.