Silk biomaterials in wound healing and skin regeneration therapeutics: From bench to bedside

Effect of silk fibroin microparticles on cellular immunity and liver of gilthead seabream (Sparus aurata L.) with and without experimental skin injuries

Silk fibroin (SF) microparticles were administered in the diet of gilthead seabream with or without experimental skin wounds to study the effects on cellular immunity and liver. A commercially available diet was enriched with varying amount of SF: 0, 50 and 100 mg kg-1 (representing the control, SF50 and SF100 diets respectively). The animals were fed for 30 days and half of them were sampled. Similar experimental wounds were then performed on the rest of fish, and they continued to be fed the same diet. At 7 days post-wounding, samples were taken from the wounded fish. Cellular immunity was studied on head kidney leucocytes (phagocytosis, respiratory and peroxidase content) and liver status (histological study and gene expression) were studied. Our results showed that experimental wounds affect both cellular immunity (by decreasing leucocyte respiratory burst and peroxidase activity) and altered liver histology (by inducing vascularisation and congestion of blood vessels). In addition, it influences the expression of genes that serve as markers of oxidative stress, endoplasmic reticulum stress and apoptosis. The highest dose of SF (SF100) increased the phagocytic capacity of leucocytes the most, as well as the expression of genes related to blood vessel formation in the liver. Furthermore, increased expression of antioxidant genes (cat and gsr) and decreased expression of genes related to reticulum endoplasmic stress (grp94 and grp170) and apoptosis (nos and jnk) were detected in these fish fed with SF100 and wounded. In conclusion, fed fish with SF100 had many beneficial effects as cellular immunostimulant and hepatoprotection in wounded fish. Its use could be of great interest for stress management in farmed fish conditions.

Expanding the boundaries of silk sericin biomaterials in biomedical applications

Silk sericin (SS) has a long history as a by-product of the textile industry. SS has emerged as a sustainable material for biomedical engineering due to its material properties including water solubility, diverse impact on biological activities including antibacterial and antioxidant properties, and ability to promote cell adhesion and proliferation. This review addresses the origin, structure, properties, extraction, and underlying functions of this protein. An overview of the growing research studies and market evolution is presented, along with highlights of the most common fabrication matrices (hydrogels, bioinks, porous and fibrous scaffolds) and tissue engineering applications. Finally, the future trends with this protein as a multifaceted toolbox for bioengineering are explored, along with the challenges with SS. Overall, the present review can serve as a foundation for the creation of innovative biomaterials utilizing SS as a fundamental building block that hold market potential.

Heparin-Functionalized Bioactive Glass to Harvest Endogenous Growth Factors for Pulp Regeneration

Pulp and periapical diseases can lead to the cessation of tooth development, resulting in compromised tooth structure and functions. Despite numerous efforts to induce pulp regeneration, effective strategies are still lacking. Growth factors (GFs) hold considerable promise in pulp regeneration due to their diverse cellular regulatory properties. However, the limited half-lives and susceptibility to degradation of exogenous GFs necessitate the administration of supra-physiological doses, leading to undesirable side effects. In this research, a heparin-functionalized bioactive glass (CaO-P2O5-SiO2-Heparin, abbreviated as PSC-Heparin) with strong bioactivity and a stable neutral pH is developed as a promising candidate to addressing challenges in pulp regeneration. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis reveal the successful synthesis of PSC-Heparin. Scanning electron microscopy and X-ray diffraction show the hydroxyapatite formation can be observed on the surface of PSC-Heparin after soaking in simulated body fluid for 12 h. PSC-Heparin is capable of harvesting various endogenous GFs and sustainably releasing them over an extended duration by the enzyme-linked immunosorbent assay. Cytological experiments show that developed PSC-Heparin can facilitate the adhesion, migration, proliferation, and odontogenic differentiation of stem cells from apical papillae. Notably, the histological analysis of subcutaneous implantation in nude mice demonstrates PSC-Heparin is capable of promoting the odontoblast-like layers and pulp-dentin complex formation without the addition of exogenous GFs, which is vital for clinical applications. This work highlights an effective strategy of harvesting endogenous GFs and avoiding the involvement of exogenous GFs to achieve pulp-dentin complex regeneration, which may open a new horizon for regenerative endodontic therapy.

Biodegradable Silk Fibroin Matrices for Wound Closure in a Human 3D Ex Vivo Approach

In this study, the potential of silk fibroin biomaterials for enhancing wound healing is explored, focusing on their integration into a human 3D ex vivo wound model derived from abdominoplasties. For this purpose, cast silk fibroin membranes and electrospun nonwoven matrices from Bombyx mori silk cocoons were compared to untreated controls over 20 days. Keratinocyte behavior and wound healing were analyzed qualitatively and quantitatively by histomorphometric and immune histochemical methods (HE, Ki67, TUNEL). Findings reveal rapid keratinocyte proliferation on both silk fibroin membrane and nonwoven matrices, along with enhanced infiltration in the matrix, suggesting improved early wound closure. Silk fibroin membranes exhibited a significantly improved early regeneration, followed by nonwoven matrices (p < 0.05) compared to untreated wounds, resulting in the formation of multi-layered epidermal structures with complete regeneration. Overall, the materials demonstrated excellent biocompatibility, supporting cell activity with no signs of increased apoptosis or early degradation. These results underscore silk fibroin's potential in clinical wound care, particularly in tissue integration and re-epithelialization, offering valuable insights for advanced and-as a result of the electrospinning technique-individual wound care development. Furthermore, the use of an ex vivo wound model appears to be a viable option for pre-clinical testing.

Silk Fibroin and Its Nanocomposites for Wound Care: A Comprehensive Review

For most individuals, wound healing is a highly organized, straightforward process, wherein the body transitions through different phases in a timely manner. However, there are instances where external intervention becomes necessary to support and facilitate different phases of the body's innate healing mechanism. Furthermore, in developing countries, the cost of the intervention significantly impacts access to treatment options as affordability becomes a determining factor. This is particularly true in cases of long-term wound treatment and management, such as chronic wounds and infections. Silk fibroin (SF) and its nanocomposites have emerged as promising biomaterials with potent wound-healing activity. Driven by this motivation, this Review presents a critical overview of the recent advancements in different aspects of wound care using SF and SF-based nanocomposites. In this context, we explore various formats of hemostats and assess their suitability for different bleeding situations. The subsequent sections discuss the primary causes of nonhealing wounds, i.e., prolonged inflammation and infections. Herein, different treatment strategies to achieve immunomodulatory and antibacterial properties in a wound dressing were reviewed. Despite exhibiting excellent pro-healing properties, few silk-based products reach the market. This Review concludes by highlighting the bottlenecks in translating silk-based products into the market and the prospects for the future.

Silk fibroin promotes H3K9me3 expression and chromatin reorganization to regulate endothelial cell proliferation

Silk fibroin (SF), which is extensively utilized in tissue engineering and vascular grafts for enhancing vascular regeneration, has not been thoroughly investigated for its epigenetic effects on endothelial cells (EC). This study employed RNA sequencing analysis to evaluate the activation of histone modification regulatory genes in EC treated with SF. Subsequent investigations revealed elevated H3K9me3 levels in SF-treated EC, as evidenced by immunofluorescence and western blot analysis. The study utilized H2B-eGFP endothelial cells to demonstrate that SF treatment results in the accumulation of H2B-marked chromatin in the nuclear inner cavities of EC. Inhibition of H3K9me3 levels by a histone deacetylase inhibitor TSA decreased cell proliferation. Furthermore, the activation of the MAPK signaling pathway using chromium picolinate decreased the proliferative activity and H3K9me3 level in SF-treated EC. SF also appeared to enhance cell growth and proliferation by modulating the H3K9me3 level and reorganizing chromatin, particularly after oxidative stress induced by H2O2 treatment. In summary, these findings indicate that SF promotes EC proliferation by increasing the H3K9me3 level even under stress conditions.

Recent advancements in natural polymers-based self-healing nano-materials for wound dressing

The field of wound healing has witnessed remarkable progress in recent years, driven by the pursuit of advanced wound dressings. Traditional dressing materials have limitations like poor biocompatibility, nonbiodegradability, inadequate moisture management, poor breathability, lack of inherent therapeutic properties, and environmental impacts. There is a compelling demand for innovative solutions to transcend the constraints of conventional dressing materials for optimal wound care. In this extensive review, the therapeutic potential of natural polymers as the foundation for the development of self-healing nano-materials, specifically for wound dressing applications, has been elucidated. Natural polymers offer a multitude of advantages, possessing exceptional biocompatibility, biodegradability, and bioactivity. The intricate engineering strategies employed to fabricate these polymers into nanostructures, thereby imparting enhanced mechanical robustness, flexibility, critical for efficacious wound management has been expounded. By harnessing the inherent properties of natural polymers, including chitosan, alginate, collagen, hyaluronic acid, and so on, and integrating the concept of self-healing materials, a comprehensive overview of the cutting-edge research in this emerging field is presented in the review. Furthermore, the inherent self-healing attributes of these materials, wherein they exhibit innate capabilities to autonomously rectify any damage or disruption upon exposure to moisture or body fluids, reducing frequent dressing replacements have also been explored. This review consolidates the existing knowledge landscape, accentuating the benefits and challenges associated with these pioneering materials while concurrently paving the way for future investigations and translational applications in the realm of wound healing.

Turning sublimed sulfur and bFGF into a nanocomposite to accelerate wound healing via co-activate FGFR and Hippo signaling pathway

Clinical treatment of diabetic refractory ulcers is impeded by chronic inflammation and cell dysfunction associated with wound healing. The significant clinical application of bFGF in wound healing is limited by its instability in vivo. Sulfur has been applied for the treatment of skin diseases in the clinic for antibiosis. We previously found that sulfur incorporation improves the ability of selenium nanoparticles to accelerate wound healing, yet the toxicity of selenium still poses a risk for its clinical application. To obtain materials with high pro-regeneration activity and low toxicity, we explored the mechanism by which selenium-sulfur nanoparticles aid in wound healing via RNA-Seq and designed a nanoparticle called Nano-S@bFGF, which was constructed from sulfur and bFGF. As expected, Nano-S@bFGF not only regenerated zebrafish tail fins and promoted skin wound healing but also promoted skin repair in diabetic mice with a profitable safety profile. Mechanistically, Nano-S@bFGF successfully coactivated the FGFR and Hippo signalling pathways to regulate wound healing. Briefly, the Nano-S@bFGF reported here provides an efficient and feasible method for the synthesis of bioactive nanosulfur and bFGF. In the long term, our results reinvigorated efforts to discover more peculiar unique biofunctions of sulfur and bFGF in a great variety of human diseases.

Development and Application of an Advanced Biomedical Material-Silk Sericin

Sericin, a protein derived from silkworm cocoons, is considered a waste product derived from the silk industry for thousands of years due to a lack of understanding of its properties. However, in recent decades, a range of exciting properties of sericin are studied and uncovered, including cytocompatibility, low-immunogenicity, photo-luminescence, antioxidant properties, as well as cell-function regulating activities. These properties make sericin-based biomaterials promising candidates for biomedical applications. This review summarizes the properties and bioactivities of silk sericin and highlights the latest developments in sericin in tissue engineering and regenerative medicine. Furthermore, the extended application of sericin in developing flexible electronic devices and 3D bioprinting is also discussed. It is believed that sericin-based biomaterials have great potential of being developed into novel tissue engineering products and smart implantable devices for various medical applications toward improving clinical outcomes.

Silk-derived sericin/fibroin mixture drink fermented with plant-derived Lactococcus lactis BM32-1 improves constipation and related microbiota: a randomized, double-blind, and placebo-controlled clinical trial

We previously showed through clinical trials that one plant-derived lactic acid bacteria (LAB) can improve constipation. We preliminarily found that the plant-derived LAB Lactococcus lactis BM32-1 can grow in a mixture of sericin and fibroin, which are extracted from silk and have been reported to help promote health. Thus, in the present study, we evaluated the favorable effect of a sericin/fibroin mixture (S/F-M), which was extracted from silk prepared from cocoons reared in an aseptic rearing system using an artificial diet, fermented with the BM32-1 strain through a clinical trial. The trial was conducted at Hiroshima University from June to October 2022 as a double-blind, placebo-controlled, randomized parallel-group comparative study with 50 eligible subjects (aged 23-71) who had an average defecation frequency of less than 5 times per week. The subjects were instructed to drink 100 mL of fermented S/F-M or placebo every day. After the 12 weeks of the clinical trial period, the average defecation frequency increased significantly-1.4 times higher than that at baseline in the test group-as compared with the placebo group. Furthermore, the fecal microbiota was also compared before and after treatment, revealing that intake of the fermented S/F-M significantly multiplied the relative abundance of the genera Enterococcus and Clostridium, which have been reported to contribute to the amelioration of constipation by improving the gut microbiota and producing butyric acid, respectively. In conclusion, the S/F-M fermented using the BM32-1 strain improves defecation frequency through alteration of the gut microbiota.

A Hydrogel Dressing Comprised of Silk Fibroin, Ag Nanoparticles, and Reduced Graphene Oxide for NIR Photothermal-Enhanced Antibacterial Efficiency and Skin Regeneration

Bacterial infection, inflammation, and excessive oxidative stress are the primary factors that contribute to delayed healing of skin wounds. In this study, a multifunctional wound dressing (SF/Ag@rGO hydrogel) is developed to promote the healing of infected skin wounds by combining the inherent antibacterial activity of Ag nanoparticles (NPs) with near-infrared (NIR)-assisted antibacterial therapy. Initially, L-ascorbic acid is used as a reducing agent and PVP-K17 as a stabilizer and dispersant, this facilitates the synthesis of reduced graphene oxide loaded with Ag NPs (Ag@rGO). Ag@rGO is then blended with a silk fibroin (SF) solution to form an instantly gelling SF/Ag@rGO hydrogel that exhibits rapid self-healing, injectability, shape adaptability, NIR responsiveness, antioxidant, high tissue adhesion, and robust mechanical properties. In vitro and in vivo experiments show that the SF/Ag@rGO hydrogel demonstrates strong antioxidant and photothermal antibacterial capabilities, promoting wound healing through angiogenesis, stimulating collagen generation, alleviating inflammation, antioxidant, and promoting cell proliferation, indicating that the SF/Ag@rGO hydrogel dressing is an ideal candidate for clinical treatment of full-thickness bacterial-stained wounds.

The Biologically Active Biopolymer Silk: The Antibacterial Effects of Solubilized Bombyx mori Silk Fibroin with Common Wound Pathogens

Antibacterial properties are desirable in wound dressings. Silks, among many material formats, have been investigated for use in wound care. However, the antibacterial properties of liquid silk are poorly understood. The aim of this study is to investigate the inherent antibacterial properties of a Bombyx mori silk fibroin solution. Silk fibroin solutions containing ≥ 4% w/v silk fibroin do not support the growth of two common wound pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. When liquid silk is added to a wound pad and placed on inoculated culture plates mimicking wound fluid, silk is bacteriostatic. Viability tests of the bacterial cells in the presence of liquid silk show that cells remain intact within the silk but could not be cultured. Liquid silk appears to provide a hostile environment for S. aureus and P. aeruginosa and inhibits growth without disrupting the cell membrane. This effect can be beneficial for wound healing and supports future healthcare applications for silk. This observation also indicates that liquid silk stored prior to processing is unlikely to experience microbial spoilage.

Harvesting Silk Fibers from Plodia interpunctella: Role of Environmental Rearing Conditions in Fiber Production and Properties

Silk fibers are produced by a wide variety of insects. The silkworm Bombyx mori (Bombyx) was domesticated because the physical properties of its silk fibers were amenable to the production of fine textiles. Subsequently, engineers have regenerated silk fibroin to form biomaterials. The monocular focus on Bombyx silk has underutilized the expanse of diverse silk proteins produced by more than 100,000 other arthropods. This vast array of silk fibers could be utilized for biomedical engineering challenges if sufficient rearing and purification processes are developed. Herein, we show that the moth, Plodia interpunctella (Plodia), represents an alternative silk source that is easily reared in highly regulated culture environments allowing for greater consistency in the silk produced. We controlled the temperature, resource availability (larvae/gram diet), and population density (larvae/mL) with the goal of increasing silk fiber production and improving homogeneity in Plodia silk proteins. We determined that higher temperatures accelerated insect growth and reduced life cycle length. Furthermore, we established initial protocols for the production of Plodia silk with optimal silk production occurring at 24 °C, with a resource availability of 10 larvae/gram and a population density of 0.72 larvae/mL. Population density was shown to be the most prominent driving force of Plodia silk mat formation among the three parameters assessed. Future work will need to link gene expression, protein production and purification, and resulting mechanical properties as a function of environmental cues to further transition Plodia silk into regenerated silk fibroin biomaterials.

Bringing innovative wound care polymer materials to the market: Challenges, developments, and new trends

The development of innovative products for treating acute and chronic wounds has become a significant topic in healthcare, resulting in numerous products and innovations over time. The growing number of patients with comorbidities and chronic diseases, which may significantly alter, delay, or inhibit normal wound healing, has introduced considerable new challenges into the wound management scenario. Researchers in academia have quickly identified promising solutions, and many advanced wound healing materials have recently been designed; however, their successful translation to the market remains highly complex and unlikely without the contribution of industry experts. This review article condenses the main aspects of wound healing applications that will serve as a practical guide for researchers working in academia and industry devoted to designing, evaluating, validating, and translating polymer wound care materials to the market. The article highlights the current challenges in wound management, describes the state-of-the-art products already on the market and trending polymer materials, describes the regulation pathways for approval, discusses current wound healing models, and offers a perspective on new technologies that could soon reach consumers. We envision that this comprehensive review will significantly contribute to highlighting the importance of networking and exchanges between academia and healthcare companies. Only through the joint of these two actors, where innovation, manufacturing, regulatory insights, and financial resources act in harmony, can wound care products be developed efficiently to reach patients quickly and affordably.

Anti-Inflammatory Peptide-Conjugated Silk Fibroin/Cryogel Hybrid Dual Fiber Scaffold with Hierarchical Structure Promotes Healing of Chronic Wounds

Chronic wounds resulting from diabetes, pressure, radiation therapy, and other factors continue to pose significant challenges in wound healing. To address this, this study introduces a novel hybrid fibroin fibrous scaffold (FFS) comprising randomly arranged fibroin fibers and vertically aligned cryogel fibers (CFs). The fibroin scaffold is efficiently degummed at room temperature and simultaneously formed a porous structure. The aligned CFs are produced via directional freeze-drying, achieved by controlling solution concentration and freezing polymerization temperature. The incorporation of aligned CFs into the expanded fibroin fiber scaffold leads to enhanced cell infiltration both in vitro and in vivo, further elevating the hybrid scaffold's tissue compatibility. The anti-inflammatory peptide 1 (AP-1) is also conjugated to the hybrid fibrous scaffold, effectively transforming the inflammatory status of chronic wounds from pro-inflammatory to pro-reparative. Consequently, the FFS-AP1+CF group demonstrates superior granulation tissue formation, angiogenesis, collagen deposition, and re-epithelialization during the proliferative phase compared to the commercial product PELNAC. Moreover, the FFS-AP1+CF group displays epidermis thickness, number of regenerated hair follicles, and collagen density closer to normal skin tissue. These findings highlight the potential of random fibroin fibers/aligned CFs hybrid fibrous scaffold as a promising approach for skin tissue filling and tissue regeneration.

A review on natural biopolymers in external drug delivery systems for wound healing and atopic dermatitis

Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.

Bioactive nanomaterials kickstart early repair processes and potentiate temporally modulated healing of healthy and diabetic wounds

Slow-healing and chronic wounds represent a major global economic and medical burden, and there is significant unmet need for novel therapies which act to both accelerate wound closure and enhance biomechanical recovery of the skin. Here, we report a new approach in which bioactives that augment early stages of wound healing can kickstart and engender effective wound closure in healthy and diabetic, obese animals, and set the stage for subsequent tissue repair processes. We demonstrate that a nanomaterial dressing made of silk fibroin and gold nanorods (GNR) stimulates a pro-neutrophilic, innate immune, and controlled inflammatory wound transcriptomic response. Further, Silk-GNR, lasered into the wound bed, in combination with exogeneous histamine, accelerates early-stage processes in tissue repair leading to effective wound closure. Silk-GNR and histamine enhanced biomechanical recovery of skin, increased transient neoangiogenesis, myofibroblast activation, epithelial-to-mesenchymal transition (EMT) of keratinocytes and a pro-resolving neutrophilic immune response, which are hitherto unknown activities for these bioactives. Predictive and temporally coordinated delivery of growth factor nanoparticles that modulate later stages of tissue repair further accelerated wound closure in healthy and diabetic, obese animals. Our approach of kickstarting healing by delivering the "right bioactive at the right time" stimulates a multifactorial, pro-reparative response by augmenting endogenous healing and immunoregulatory mechanisms and highlights new targets to promote tissue repair.

Fabrication of Quercetin-Functionalized Morpholine and Pyridine Motifs-Laden Silk Fibroin Nanofibers for Effective Wound Healing in Preclinical Study

Choosing suitable wound dressings is crucial for effective wound healing. Spun scaffolds with bioactive molecule functionalization are gaining attention as a promising approach to expedite tissue repair and regeneration. Here, we present the synthesis of novel multifunctional quercetin with morpholine and pyridine functional motifs (QFM) embedded in silk fibroin (SF)-spun fibers (SF-QFM) for preclinical skin repair therapies. The verification of the novel QFM structural arrangement was characterized using ATR-FTIR, NMR, and ESI-MS spectroscopy analysis. Extensive characterization of the spun SF-QFM fibrous mats revealed their excellent antibacterial and antioxidant properties, biocompatibility, biodegradability, and remarkable mechanical and controlled drug release capabilities. SF-QFM mats were studied for drug release in pH 7.4 PBS over 72 h. The QFM-controlled release is mainly driven by diffusion and follows Fickian's law. Significant QFM release (40%) occurred within the first 6 h, with a total release of 79% at the end of 72 h, which is considered beneficial in effectively reducing bacterial load and helping expedite the healing process. Interestingly, the SF-QFM-spun mat demonstrated significantly improved NIH 3T3 cell proliferation and migration compared to the pure SF mat, as evidenced by the complete migration of NIH 3T3 cells within 24 h in the scratch assay. Furthermore, the in vivo outcome of SF-QFM was demonstrated by the regeneration of fresh fibroblasts and the realignment of collagen fibers deposition at 9 days post-operation in a preclinical rat full-thickness skin defect model. Our findings collectively indicate that the SF-QFM electrospun nanofiber scaffolds hold significant capability as a cost-effective and efficient bioactive spun architecture for use in wound healing applications.

Surface modification strategies for improved hemocompatibility of polymeric materials: a comprehensive review

Polymeric biomaterials are a widely used class of materials due to their versatile properties. However, as with all other types of materials used for biomaterials, polymers also have to interact with blood. When blood comes into contact with any foreign body, it initiates a cascade which leads to platelet activation and blood coagulation. The implant surface also has to encounter a thromboinflammatory response which makes the implant integrity vulnerable, this leads to blood coagulation on the implant and obstructs it from performing its function. Hence, the surface plays a pivotal role in the design and application of biomaterials. In particular, the surface properties of biomaterials are responsible for biocompatibility with biological systems and hemocompatibility. This review provides a report on recent advances in the field of surface modification approaches for improved hemocompatibility. We focus on the surface properties of polysaccharides, proteins, and synthetic polymers. The blood coagulation cascade has been discussed and blood - material surface interactions have also been explained. The interactions of blood proteins and cells with polymeric material surfaces have been discussed. Moreover, the benefits as well as drawbacks of blood coagulation on the implant surface for wound healing purposes have also been studied. Surface modifications implemented by other researchers to enhance as well as prevent blood coagulation have also been analyzed.

Silk-Fabric Reinforced Silk for Artificial Bones

Bone implants for different body parts require varying mechanical properties, dimensions, and biodegradability rates. Currently, it is still challenging to produce artificial bones with perfect compatibility with human bones. In this study, a silk-fabric reinforced silk material (SFS) composed of pure silk with exceptional biocompatibility, osteogenesis, and biodegradability is reported, and demonstrates its outstanding performance as a bone implant material. The SFS is fabricated using a simple hot-pressing technique, with degummed silk fabric as the reinforcement and silk fibroin as the matrix. The SFS as a self-reinforced composite, has exceptional mechanical properties due to the almost perfect interface between the matrix and reinforcement. More importantly, its mechanical properties, biodegradability rates, and density can be tailored by adjusting the reinforcement structure and the ratio of the reinforcement to the matrix to align with the requirements for bone implantation in different parts of the human body. Besides, the SFS can improve osteoblastic proliferation and increase osteogenic activity, which is not the case with clinically used titanium alloy artificial bone. Therefore, the SFS holds significant potential to replace conventional metal or ceramic implants in the field of medical fracture repair.

Piezoelectric dressings for advanced wound healing

The treatment of chronic refractory wounds poses significant challenges and threats to both human society and the economy. Existing research studies demonstrate that electrical stimulation fosters cell proliferation and migration and promotes the production of cytokines that expedites the wound healing process. Presently, clinical settings utilize electrical stimulation devices for wound treatment, but these devices often present issues such as limited portability and the necessity for frequent recharging. A cutting-edge wound dressing employing the piezoelectric effect could transform mechanical energy into electrical energy, thereby providing continuous electrical stimulation and accelerating wound healing, effectively addressing these concerns. This review primarily reviews the selection of piezoelectric materials and their application in wound dressing design, offering a succinct overview of these materials and their underlying mechanisms. This study also provides a perspective on the current limitations of piezoelectric wound dressings and the future development of multifunctional dressings harnessing the piezoelectric effect.

Doping of casted silk fibroin membranes with extracellular vesicles for regenerative therapy: a proof of concept

Bioactive material concepts for targeted therapy have been an important research focus in regenerative medicine for years. The aim of this study was to investigate a proof-of-concept composite structure in the form of a membrane made of natural silk fibroin (SF) and extracellular vesicles (EVs) from gingival fibroblasts. EVs have multiple abilities to act on their target cell and can thus play crucial roles in both physiology and regeneration. This study used pH neutral, degradable SF-based membranes, which have excellent cell- and tissue-specific properties, as the carrier material. The characterization of the vesicles showed a size range between 120 and 180 nm and a high expression of the usual EV markers (e.g. CD9, CD63 and CD81), measured by nanoparticle tracking analysis (NTA) and single-EV flow analysis (IFCM). An initial integration of the EVs into the membrane was analyzed using scanning and transmission electron microscopy (SEM and TEM) and vesicles were successfully detected, even if they were not homogeneously distributed in the membrane. Using direct and indirect tests, the cytocompatibility of the membranes with and without EVs could be proven and showed significant differences compared to the toxic control (p < 0.05). Additionally, proliferation of L929 cells was increased on membranes functionalized with EVs (p > 0.05).

Hydrogel-mediated extracellular vesicles for enhanced wound healing: the latest progress, and their prospects for 3D bioprinting

Extracellular vesicles have shown promising tissue recovery-promoting effects, making them increasingly sought-after for their therapeutic potential in wound treatment. However, traditional extracellular vesicle applications suffer from limitations such as rapid degradation and short maintenance during wound administration. To address these challenges, a growing body of research highlights the role of hydrogels as effective carriers for sustained extracellular vesicle release, thereby facilitating wound healing. The combination of extracellular vesicles with hydrogels and the development of 3D bioprinting create composite hydrogel systems boasting excellent mechanical properties and biological activity, presenting a novel approach to wound healing and skin dressing. This comprehensive review explores the remarkable mechanical properties of hydrogels, specifically suited for loading extracellular vesicles. We delve into the diverse sources of extracellular vesicles and hydrogels, analyzing their integration within composite hydrogel formulations for wound treatment. Different composite methods as well as 3D bioprinting, adapted to varying conditions and construction strategies, are examined for their roles in promoting wound healing. The results highlight the potential of extracellular vesicle-laden hydrogels as advanced therapeutic tools in the field of wound treatment, offering both mechanical support and bioactive functions. By providing an in-depth examination of the various roles that these composite hydrogels can play in wound healing, this review sheds light on the promising directions for further research and development. Finally, we address the challenges associated with the application of composite hydrogels, along with emerging trends of 3D bioprinting in this domain. The discussion covers issues such as scalability, regulatory considerations, and the translation of this technology into practical clinical settings. In conclusion, this review underlines the significant contributions of hydrogel-mediated extracellular vesicle therapy to the field of 3D bioprinting and wound healing and tissue regeneration. It serves as a valuable resource for researchers and practitioners alike, fostering a deeper understanding of the potential benefits, applications, and challenges involved in utilizing composite hydrogels for wound treatment.

Natural agents as wound-healing promoters

The management of acute and chronic wounds resulting from diverse injuries poses a significant challenge to clinical practices and healthcare providers. Wound healing is a complex biological process driven by a natural physiological response. This process involves four distinct phases, namely hemostasis, inflammation, proliferation, and remodeling. Despite numerous investigations on wound healing and wound dressing materials, complications still persist, necessitating more efficacious therapies. Wound-healing materials can be categorized into natural and synthetic groups. The current study aims to provide a comprehensive review of highly active natural animal and herbal agents as wound-healing promoters. To this end, we present an overview of in vitro, in vivo, and clinical studies that led to the discovery of potential therapeutic agents for wound healing. We further elucidated the effects of natural materials on various pharmacological pathways of wound healing. The results of previous investigations suggest that natural agents hold great promise as viable and accessible products for the treatment of diverse wound types.

Electrospun fibers based anisotropic silk fibroin film with photodynamic antibacterial therapy for S. aureus infected wound healing

Bacterial infection has been regarded as a life-threatening problem in clinic. In addition to screening of new antibiotics, it is important to develop highly effective antibacterial materials against antibiotic resistance with capacities on modulating chronic inflammation. Herein, aligned Chlorin e6 (Ce6) conjugated silk fibroin electrospun fibers were successfully fabricated on silk fibroin based film via electrospining to achieve effective photodynamic antibacterial activities under near infrared (NIR) irradiation. The aligned electrospun fiber based film composite (SFCF@Film) exhibited good mechanical properties and desirable hemocompatibility. SFCF@Film provided a promising guidance cue for directing cell orientation and promoting cell growth. Significantly, SFCF@Film effectively generated ROS under NIR irradiation to kill S. aureus for treating wound infections within 10 min and promoted M2 polarization of macrophages for wound healing at later stage. Therefore, we believed that this engineered bioscaffold can be a powerful strategy for handling wound infection.

Evaluation of wound healing active principles in the transdermal patch formulated with crude bio wastes and plant extracts against GSK-3 beta - an in silico study

The wound-healing process is accelerated by inhibiting proteins that decelerate the wound-healing pathway. One of the active proteins involved in enhancing healing at the nuclear level and in gene expression is catenin. Inhibition of Glycogen Synthase Kinase 3β (GSK3 β) phosphorylates and degrades catenin via the downstream Wnt signalling pathway, thereby stabilizing catenin. A medicated wound dressing transdermal patch designed with fusion of bio wastes, viz. physiologically clotted fibrin, fish scale collagen, and the ethanolic extract of Mangifera indica (L.) and spider web, was analysed against GSK3β to enhance healing. In our earlier studies, the compounds present in the transdermal patch were identified using GC-MS analysis; 12 compounds exhibiting the wound healing mechanism were analyzed using PASS software and filtered out. From these 12 compounds, 6 compounds that possessed drug-likeness were screened by SwissADME and vNN-ADMET to dock against GSK3β in the present work. The PyRx results confirmed the binding of the six ligands to the active site of the target protein. Though the remaining filtered ligands also exhibited inhibitory activity, Molecular dynamics simulation studies were carried out with 100 ns on a complex of 10,12 Tricosadiyonic acid, Nopyl acetate and 2 Methyl 4 Heptanol as they showed binding affinity of -6.2Kcal/mol, -5.7Kcal/mol and -5.1Kcal/mol respectively. The stability of the complex was validated using MD simulation parameters RMSD, RMSF, Rg, and Number of Hydrogen bonds. These results implied that the transdermal patch would be efficient in accelerating the wound healing process through the inactivation of GSK3β.Communicated by Ramaswamy H. Sarma.

Silk fibroin-derived electrospun materials for biomedical applications: A review

Electrospinning is a versatile technique for fabricating polymeric fibers with diameters ranging from micro- to nanoscale, exhibiting multiple morphologies and arrangements. By combining silk fibroin (SF) with synthetic and/or natural polymers, electrospun materials with outstanding biological, chemical, electrical, physical, mechanical, and optical properties can be achieved, fulfilling the evolving biomedical demands. This review highlights the remarkable versatility of SF-derived electrospun materials, specifically focusing on their application in tissue regeneration (including cartilage, cornea, nerves, blood vessels, bones, and skin), disease treatment (such as cancer and diabetes), and the development of controlled drug delivery systems. Additionally, we explore the potential future trends in utilizing these nanofibrous materials for creating intelligent biomaterials, incorporating biosensors and wearable sensors for monitoring human health, and also discuss the bottlenecks for its widespread use. This comprehensive overview illuminates the significant impact and exciting prospects of SF-derived electrospun materials in advancing biomedical research and applications.

Current Biomaterials for Wound Healing

Wound healing is the body's process of injury recovery. Skin healing is divided into four distinct overlapping phases: hemostasis, inflammation, proliferation, and remodeling. Cell-to-cell interactions mediated by both cytokines and chemokines are imperative for the transition between these phases. Patients can face difficulties in the healing process due to the wound being too large, decreased vascularization, infection, or additional burdens of a systemic illness. The field of tissue engineering has been investigating biomaterials as an alternative for skin regeneration. Biomaterials used for wound healing may be natural, synthetic, or a combination of both. Once a specific biomaterial is selected, it acts as a scaffold for skin regeneration. When the scaffold is applied to a wound, it allows for the upregulation of distinct molecular signaling pathways important for skin repair. Although tissue engineering has made great progress, more research is needed in order to support the use of biomaterials for wound healing for clinical translation.

Applications of Silk Fibroin in Human and Veterinary Medicine

The properties of silk make it a promising material for medical applications, both in human and veterinary medicine. Its predominant amino acids, glycine and alanine, exhibit low chemical reactivity, reducing the risk of graft rejection, a notable advantage over most synthetic polymers. Hence, silk is increasingly used as a material for 3D printing in biomedicine. It can be used to build cell scaffolding with the desired cytocompatibility and biodegradability. In combination with gelatine, silk can be used in the treatment of arthritis, and as a hydrogel, to regenerate chondrocytes and mesenchymal cells. When combined with gelatine and collagen, it can also make skin grafts and regenerate the integumentary system. In the treatment of bone tissue, it can be used in combination with polylactic acid and hydroxyapatite to produce bone clips having good mechanical properties and high immunological tolerance. Furthermore, silk can provide a good microenvironment for the proliferation of bone marrow stem cells. Moreover, research is underway to produce artificial blood vessels using silk in combination with glycidyl methacrylate. Silk vascular grafts have demonstrated a high degree of patency and a satisfactory degree of endothelial cells coverage.

Tailored biomedical materials for wound healing

Wound healing is a long-term, multi-stage biological process that mainly includes haemostatic, inflammatory, proliferative and tissue remodelling phases. Controlling infection and inflammation and promoting tissue regeneration can contribute well to wound healing. Smart biomaterials offer significant advantages in wound healing because of their ability to control wound healing in time and space. Understanding how biomaterials are designed for different stages of wound healing will facilitate future personalized material tailoring for different wounds, making them beneficial for wound therapy. This review summarizes the design approaches of biomaterials in the field of anti-inflammatory, antimicrobial and tissue regeneration, highlights the advanced precise control achieved by biomaterials in different stages of wound healing and outlines the clinical and practical applications of biomaterials in wound healing.

Material matters: exploring the interplay between natural biomaterials and host immune system

Biomaterials are widely used for various medical purposes, for instance, implants, tissue engineering, medical devices, and drug delivery systems. Natural biomaterials can be obtained from proteins, carbohydrates, and cell-specific sources. However, when these biomaterials are introduced into the body, they trigger an immune response which may lead to rejection and failure of the implanted device or tissue. The immune system recognizes natural biomaterials as foreign substances and triggers the activation of several immune cells, for instance, macrophages, dendritic cells, and T cells. These cells release pro-inflammatory cytokines and chemokines, which recruit other immune cells to the implantation site. The activation of the immune system can lead to an inflammatory response, which can be beneficial or detrimental, depending on the type of natural biomaterial and the extent of the immune response. These biomaterials can also influence the immune response by modulating the behavior of immune cells. For example, biomaterials with specific surface properties, such as charge and hydrophobicity, can affect the activation and differentiation of immune cells. Additionally, biomaterials can be engineered to release immunomodulatory factors, such as anti-inflammatory cytokines, to promote a tolerogenic immune response. In conclusion, the interaction between biomaterials and the body's immune system is an intricate procedure with potential consequences for the effectiveness of therapeutics and medical devices. A better understanding of this interplay can help to design biomaterials that promote favorable immune responses and minimize adverse reactions.

Application of silk fibroin coatings for biomaterial surface modification: a silk road for biomedicine

Silk fibroin (SF) as a natural biopolymer has become a popular material for biomedical applications due to its minimal immunogenicity, tunable biodegradability, and high biocompatibility. Nowadays, various techniques have been developed for the applications of SF in bioengineering. Most of the literature reviews focus on the SF-based biomaterials and their different forms of applications such as films, hydrogels, and scaffolds. SF is also valuable as a coating on other substrate materials for biomedicine; however, there are few reviews related to SF-coated biomaterials. Thus, in this review, we focused on the surface modification of biomaterials using SF coatings, demonstrated their various preparation methods on substrate materials, and introduced the latest procedures. The diverse applications of SF coatings for biomedicine are discussed, including bone, ligament, skin, mucosa, and nerve regeneration, and dental implant surface modification. SF coating is conducive to inducing cell adhesion and migration, promoting hydroxyapatite (HA) deposition and matrix mineralization, and inhibiting the Notch signaling pathway, making it a promising strategy for bone regeneration. In addition, SF-coated composite scaffolds can be considered prospective candidates for ligament regeneration after injury. SF coating has been proven to enhance the mechanical properties of the substrate material, and render integral stability to the dressing material during the regeneration of skin and mucosa. Moreover, SF coating is a potential strategy to accelerate nerve regeneration due to its dielectric properties, mechanical flexibility, and angiogenesis promotion effect. In addition, SF coating is an effective and popular means for dental implant surface modification to promote osteogenesis around implants made of different materials. Thus, this review can be of great benefit for further improvements in SF-coated biomaterials, and will undoubtedly contribute to clinical transformation in the future.

Harnessing gradient gelatin nanocomposite hydrogels: a progressive approach to tackling antibacterial biofilms

Infectious wounds pose significant challenges due to their susceptibility to bacterial infections, hindering tissue repair. This study introduces gradient gelatin nanocomposite hydrogels for wound healing and antibacterial biofilm management. These hydrogels, synthesized via UV light polymerization, incorporate copper-doped polydopamine nanoparticles (PDA-Cu) and GelMA (gelatin methacrylate). The hydrogels have a unique structure with a porous upper layer and a denser lower layer, ensuring superior swelling (over than 600%) and effective contact with bacterial biofilms. In vitro experiments demonstrate their remarkable antibacterial properties, inhibiting S. aureus and E. coli biofilms by over 45% and 53%, respectively. This antibacterial action is attributed to the regulation of reactive oxygen species (ROS) production, an alternative mechanism to bacterial cell wall disruption. Moreover, the hydrogels exhibit high biocompatibility with mammalian cells, making them suitable for medical applications. In vivo evaluation in a rat wound infection model shows that the gradient hydrogel treatment effectively controls bacterial biofilm infections and accelerates wound healing. The treated wounds have smaller infected areas and reduced bacterial colony counts. Histological analysis reveals reduced inflammation and enhanced granulation tissue formation in treated wounds, highlighting the therapeutic potential of these gradient nanocomposite hydrogels. In summary, gradient gelatin nanocomposite hydrogels offer promising multifunctional capabilities for wound healing and biofilm-related infections, paving the way for innovative medical dressings with enhanced antibacterial properties and biocompatibility.

Silk Nanofiber Scaffolds with Multiple Angiogenic Cues to Accelerate Wound Regeneration

Niches with multiple physical and chemical cues can influence the fate of cells and tissues in vivo. Simulating the in vivo niche in the design of bioactive materials is a challenge, particularly to tune multiple cues simultaneously in the same system. Here, an assembly strategy was developed to regulate multiple cues in the same scaffold based on the use of two silk nanofiber components that respond differently during the fabrication processes. An aqueous solution containing the two components, amorphous silk nanofibers (ASNFs) and β-sheet-rich silk nanofibers (BSNFs), was sequentially treated with an electrical field and freeze-drying processes where the BSNFs oriented to the electrical field, while the ASNFs formed stable porous structures during the lyophilization process to impact the mechanical properties. Bioactive cargo, such as deferoxamine (DFO), was loaded on the BSNFs to enrich cell responses with the scaffolds. The in vitro results revealed that the loaded DFO and the anisotropic structures with improved mechanical properties resulted in better vascularization than those of the scaffolds without the anisotropic features. The multiple cues in the scaffolds provided angiogenic niches to accelerate wound healing.

A comprehensive review of recent advances in silk sericin: Extraction approaches, structure, biochemical characterization, and biomedical applications

Silks are natural polymers that have been widely used for centuries. Silk consists of a filament core protein, termed fibroin, and a glue-like coating substance formed of sericin (SER) proteins. This protein is extracted from the silkworm cocoons (particularly Bombyx mori) and is mainly composed of amino acids like glycine, serine, aspartic acid, and threonine. Silk SER can be obtained using numerous methods, including enzymatic extraction, high-temperature, autoclaving, ethanol precipitation, cross-linking, and utilizing acidic, alkali, or neutral aqueous solutions. Given the versatility and outstanding properties of SER, it is widely fabricated to produce sponges, films, and hydrogels for further use in diverse biomedical applications. Hence, many authors reported that SER benefits cell proliferation, tissue engineering, and skin tissue restoration thanks to its moisturizing features, antioxidant and anti-inflammatory properties, and mitogenic effect on mammalian cells. Remarkably, SER is used in drug delivery depending on its chemical reactivity and pH-responsiveness. These unique features of SER enhance the bioactivity of drugs, facilitating the fabrication of biomedical materials at nano- and microscales, hydrogels, and conjugated molecules. This review thoroughly outlines the extraction techniques, biological properties, and respective biomedical applications of SER.

Lychnophora ericoides Mart. (Brazilian arnica) ethanol extract accelerates the skin wound healing process: Evidence for its mechanism of action

BACKGROUND

Lychnophora ericoides Mart, also known as the Brazilian arnica or fake arnica, belongs to the Asteraceae family. Leaves and roots are used in alcoholic and hydroalcoholic preparations for the treatment of wounds, inflammation, and pain.

PURPOSE

The present study aimed to investigate the effects of L. ericoides ethanolic extract (EELE) on cutaneous wound healing and the mechanisms of action involved.

METHODS

A total of 72 C57BL/6 mice were randomly divided into four groups of six animals each. An excisional wound was made in the dorsal region of each mouse. The test groups were topically treated with the vehicle, a positive control commercial reference drug, EELE ointment (5%), and EELE ointment (10%). The treatments were applied over 14 days. The wound area was measured every two days to verify the wound closure kinetics. On days 3, 7, and 14 the wound tissue samples were processed for Hematoxylin and Eosin, Masson-Trichrome, and Toluidine blue staining. The expression of renin-angiotensin system (RAS) components, the vascular growth factor-A (VEGF-A), the basic fibroblast growth factor (FGF-2), and type I collagen genes were evaluated. Phytochemical analyses were performed using HPLC-DAD and HPLC-MS/MS.

RESULTS

The EELE (10%) significantly reduced the wound area compared to the treatments used for the other groups. Histological analysis demonstrated that wounds treated with L. ericoides for 14 days developed improved anatomical skin features, healed with hair follicles and sebaceous glands, increased collagen production and angiogenesis, and decreased the number of mast cells at the injury site. Real-time PCR data demonstrated that groups treated with EELE (10%) showed increased Type I collagen, VEGF-A, FGF-2, and AT1R and decreased ACE II and receptor MAS. The healing action of L. ericoides may be related to the presence of phenolic compounds, such as phenolic acids, chlorogenic acid derivatives, and C-glycoside flavonoids.

CONCLUSION

Topical treatment with EELE increases important factors for wound healing: FGF, VEGF, collagen formation, and the expression of the proliferative axis of the renin-angiotensin system. For the first time, the present study shows the healing action of L. ericoides at the molecular level in an animal model. This process can be used as an alternative therapy for wound healing and the development of herbal therapy.

Evaluation and Application of Silk Fibroin Based Biomaterials to Promote Cartilage Regeneration in Osteoarthritis Therapy

Osteoarthritis (OA) is a common joint disease characterized by cartilage damage and degeneration. Traditional treatments such as NSAIDs and joint replacement surgery only relieve pain and do not achieve complete cartilage regeneration. Silk fibroin (SF) biomaterials are novel materials that have been widely studied and applied to cartilage regeneration. By mimicking the fibrous structure and biological activity of collagen, SF biomaterials can promote the proliferation and differentiation of chondrocytes and contribute to the formation of new cartilage tissue. In addition, SF biomaterials have good biocompatibility and biodegradability and can be gradually absorbed and metabolized by the human body. Studies in recent years have shown that SF biomaterials have great potential in treating OA and show good clinical efficacy. Therefore, SF biomaterials are expected to be an effective treatment option for promoting cartilage regeneration and repair in patients with OA. This article provides an overview of the biological characteristics of SF, its role in bone and cartilage injuries, and its prospects in clinical applications to provide new perspectives and references for the field of bone and cartilage repair.

An All-In-One Transient Theranostic Platform for Intelligent Management of Hemorrhage

Developing theranostic devices to detect bleeding and effectively control hemorrhage in the prehospital setting is an unmet medical need. Herein, an all-in-one theranostic platform is presented, which is constructed by sandwiching silk fibroin (SF) between two silver nanowire (AgNW) based conductive electrodes to non-enzymatically diagnose local bleeding and stop the hemorrhage at the wound site. Taking advantage of the hemostatic property of natural SF, the device is composed of a shape-memory SF sponge, facilitating blood clotting, with ≈82% reduction in hemostatic time in vitro as compared with untreated blood. Furthermore, this sandwiched platform serves as a capacitive sensor that can detect bleeding and differentiate between blood and other body fluids (i.e., serum and water) via capacitance change. In addition, the AgNW electrode endows anti-infection efficiency against Escherichia coli and Staphylococcus aureus. Also, the device shows excellent biocompatibility and gradually biodegrades in vivo with no major local or systemic inflammatory responses. More importantly, the theranostic platform presents considerable hemostatic efficacy comparable with a commercial hemostat, Dengen, in rat liver bleeding models. The theranostic platform provides an unexplored strategy for the intelligent management of hemorrhage, with the potential to significantly improve patients' well-being through the integration of diagnostic and therapeutic capabilities.

Engineered biomimetic micro/nano-materials for tissue regeneration

The incidence of tissue and organ damage caused by various diseases is increasing worldwide. Tissue engineering is a promising strategy of tackling this problem because of its potential to regenerate or replace damaged tissues and organs. The biochemical and biophysical cues of biomaterials can stimulate and induce biological activities such as cell adhesion, proliferation and differentiation, and ultimately achieve tissue repair and regeneration. Micro/nano materials are a special type of biomaterial that can mimic the microstructure of tissues on a microscopic scale due to its precise construction, further providing scaffolds with specific three-dimensional structures to guide the activities of cells. The study and application of biomimetic micro/nano-materials have greatly promoted the development of tissue engineering. This review aims to provide an overview of the different types of micro/nanomaterials, their preparation methods and their application in tissue regeneration.

Diabetic wound healing potential of silk sericin protein based hydrogels enriched with plant extracts

The complications associated with diabetic wounds make their healing process prolonged. Hydrogels could be ideal wound dressings therefore present research was conducted to prepare silk sericin (an adhesive protein polymer) based hydrogels in combination with plant extracts and to evaluate its effectiveness against wound healing process in mice with alloxan induced diabetes. Excision wounds were formed via a biopsy puncture (6 mm). Experimental hydrogels were prepared and applied topically on the diabetic wounds. All the hydrogel treatment groups showed significantly higher (P < 0.001) percent wound contraction from day 3 to day 11 as compared to the negative diabetic control group. The serum level of anti-inflammatory cytokine (Interleukin-10) and tissue inhibitor metalloproteinase (TIMP) was significantly higher (P < 0.001), while the level of pro-inflammatory cytokines (tumor necrosis factor-α, Interleukin-6) and matrix metalloproteinases (MMP-2, MMP-9) was significantly lower (P < 0.001) in hydrogels treatment groups as compared to diabetic control group. Although all the hydrogels showed effective results, however the best results were shown by 4 % sericin+4 % banyan+4 % onion based hydrogel. It can be concluded that Sericin based hydrogel enriched with banyan and onion extracts can be used as an effective remedy for the treatment of diabetic wounds due to their high healing and regenerative properties.

In situ photo-crosslinking silk fibroin based hydrogel accelerates diabetic wound healing through antibacterial and antioxidant

Bacterial infection and excessive reactive oxygen species (ROS) in diabetic wounds lead to a prolonged inflammatory phase, and injuries are highly susceptible to developing into chronic wounds. Improving the poor microenvironment is vital to achieving effective diabetic wound healing. In this work, methacrylated silk fibroin (SFMA) was combined with ε-polylysine (EPL) and manganese dioxide nanoparticles (BMNPs) to form an SF@(EPL-BM) hydrogel with in situ forming, antibacterial and antioxidant properties. EPL imparted high antibacterial activity (>96 %) to the hydrogel. BMNPs and EPL showed good scavenging activity against a variety of free radicals. SF@(EPL-BM) hydrogel had low cytotoxicity and could alleviate H₂O₂-induced oxidative stress in L929 cells. In diabetic wounds infected with Staphylococcus aureus (S. aureus), the SF@(EPL-BM) hydrogel exhibited better antibacterial properties and reduced wound ROS levels more significantly than that of the control in vivo. In this process, the pro-inflammatory factor TNF-α was down-regulated, and the vascularization marker CD31 was up-regulated. H&E and Masson staining showed a rapid transition from the inflammatory to the proliferative phase of the wounds, with significant new tissue and collagen deposition. These results confirm that this multifunctional hydrogel dressing holds well potential for chronic wound healing.

Silk sericin conjugated magnesium oxide nanoparticles for its antioxidant, anti-aging, and anti-biofilm activities

The Silk sericin protein was conjugated with magnesium oxide (MgO) nanoparticles to form SS-MgO-NPs . UV, XRD, FTIR, SEM, DLS, and EDX were used to confirm the formation of SS-MgO-NPs. The absorption band of SS-MgO-NPs using UV-visible spectra was observed at 310 nm, with an average size of the nanoparticles was 65-88 nm analyzed from DLS. The presence of alcohol, CN, and CC, alkanes, alkenes, and cis alkenes, in silk sericin, is confirmed by FT-IR and may act as a stabilizing agent. Later SS-MgO-NPs were evaluated for antioxidant, antibacterial, anti-biofilm, ,anti-aging, and anticancer properties. The SS-MgO-NPs inhibited the formation of biofilm of Pseudomonas aeruginosa and Bacillus cereus. The blood compatibility of SS-MgO-NPs, delaying coagulation was observed using human, blood, and goat blood samples. The SS-MgO-NPs exhibited significant anticancer activity on MCF-7 (IC₅₀ 207.6 μg/mL) cancer cell lines. Correspondingly, SS-MgO-NPs demonstrated dose-dependent inhibition of the enzymes in the following order collagenase > elastase > tyrosinase > hyaluronidase, with IC₅₀ values of 75.3, 85.3, 133.6, and 156.3 μgmL^-1, respectively. This exhibits the compoundposses anti-aging properties. So, in in vitro settings, SS-MgO-NPs can be used as an antibacterial, anti-aging, and anticancer agent. Additionally, in vivo research is necessary to validate its therapeutic applications.

Recent Tissue Engineering Approaches to Mimicking the Extracellular Matrix Structure for Skin Regeneration

Inducing tissue regeneration in many skin defects, such as large traumatic wounds, burns, other physicochemical wounds, bedsores, and chronic diabetic ulcers, has become an important clinical issue in recent years. Cultured cell sheets and scaffolds containing growth factors are already in use but have yet to restore normal skin tissue structure and function. Many tissue engineering materials that focus on the regeneration process of living tissues have been developed for the more versatile and rapid initiation of treatment. Since the discovery that cells recognize the chemical-physical properties of their surrounding environment, there has been a great deal of work on mimicking the composition of the extracellular matrix (ECM) and its three-dimensional network structure. Approaches have used ECM constituent proteins as well as morphological processing methods, such as fiber sheets, sponges, and meshes. This review summarizes material design strategies in tissue engineering fields, ranging from the morphology of existing dressings and ECM structures to cellular-level microstructure mimicry, and explores directions for future approaches to precision skin tissue regeneration.

Skin mucus metabolomics provides insights into the interplay between diet and wound in gilthead seabream (Sparus aurata)

The molecular processes underlying skin wound healing in several fish species have been elucidated in the last years, however, metabolomic insights are scarce. Here we report the skin mucus metabolome of wounded and non-wounded gilthead seabream (Sparus aurata) fed with silk fibroin microparticles, a functional additive considered to accelerate the wound healing process. The three experimental diets (commercial diet enriched with 0 mg (control), 50 mg or 100 mg of silk fibroin microparticles Kg^-1) were administered for 30 days and thereafter, a skin wound was inflicted. Skin mucus was collected on day 30 of feeding and 7 days post-wounding and subjected to metabolomic analysis by Ultra Performance Liquid Chromatography coupled with a high-resolution quadrupole-orbitrap mass spectrometry. The most enriched metabolite class was amino acids and derivatives, followed by nucleotides, nucleosides and analogues and carbohydrates and their derivatives. Metabolomic profiles revealed that the diet had a more profound effect than wounding in skin mucus. Metabolic pathway analysis of significantly affected metabolites revealed perturbations in the aminoacyl t-RNA biosynthesis in the skin. In particular, skin wound resulted in a decreased methionine level in mucus. Further, silk fibroin supplementation increased methionine level in skin mucus, which correlated with several wound morphometric parameters that characterized the epithelial healing capacity in seabream. The results provided new insight into the physiological consequences of skin wounds and how these processes could be influenced by dietary manipulation.

Therapeutic Efficacy of Polymeric Biomaterials in Treating Diabetic Wounds-An Upcoming Wound Healing Technology

Diabetic wounds are one of the serious, non-healing, chronic health issues faced by individuals suffering from diabetic mellitus. The distinct phases of wound healing are either prolonged or obstructed, resulting in the improper healing of diabetic wounds. These injuries require persistent wound care and appropriate treatment to prevent deleterious effects such as lower limb amputation. Although there are several treatment strategies, diabetic wounds continue to be a major threat for healthcare professionals and patients. The different types of diabetic wound dressings that are currently used differ in their properties of absorbing wound exudates and may also cause maceration to surrounding tissues. Current research is focused on developing novel wound dressings incorporated with biological agents that aid in a faster rate of wound closure. An ideal wound dressing material must absorb wound exudates, aid in the appropriate exchange of gas, and protect from microbial infections. It must support the synthesis of biochemical mediators such as cytokines, and growth factors that are crucial for faster healing of wounds. This review highlights the recent advances in polymeric biomaterial-based wound dressings, novel therapeutic regimes, and their efficacy in treating diabetic wounds. The role of polymeric wound dressings loaded with bioactive compounds, and their in vitro and in vivo performance in diabetic wound treatment are also reviewed.

Recent Developments in Biopolymer-Based Hydrogels for Tissue Engineering Applications

Hydrogels are being investigated for their application in inducing the regeneration of various tissues, and suitable conditions for each tissue are becoming more apparent. Conditions such as the mechanical properties, degradation period, degradation mechanism, and cell affinity can be tailored by changing the molecular structure, especially in the case of polymers. Furthermore, many high-functional hydrogels with drug delivery systems (DDSs), in which drugs or bioactive substances are contained in controlled hydrogels, have been reported. This review focuses on the molecular design and function of biopolymer-based hydrogels and introduces recent developments in functional hydrogels for clinical applications.

Betamethasone-loaded dissolvable microneedle patch for oral ulcer treatment

Oral inflammatory disease (OID) is among the most common oral lesions, affecting people's quality of life and even leading to oral cancer. Oral ulcers are the most common OID. However, the pain and fear caused by the localized injection of hormones hinder the clinical treatment of oral ulcers. To address this problem, soluble hyaluronic acid (HA) microneedle patches (BSP-BDP@HAMN) containing betamethasone 21-phosphate sodium (BSP) and betamethasone 17,21-dipropionate (BDP) were fabricated for potential application in oral ulcers. BSP-BDP@HAMNs had the sufficient mechanical strength to penetrate the rat tongue abdomen mucosa with an insertion depth of approximately 207 ± 3 µm. The rapidly solubilized HA microneedle carrier released BSP and BDP into the ulcer base within 3 min of entering the mucosa. Cellular assays have shown that BDP@HAMNs have wound healing-promoting and anti-inflammatory effects. Compared with topical injections and creams, BSP-BDP@HAMNs not only penetrated the ulcer surface painlessly but also worked deep in the ulcer for a long time. In conclusion, the proposed BSP-BDP@HAMN patch can improve the comfort and efficacy of oral ulcer treatment, thus providing a new prospect for oral ulcer treatment.

Porous composite hydrogels with improved MSC survival for robust epithelial sealing around implants and M2 macrophage polarization

The application of mesenchymal stem cell (MSC)-based therapy is expected to make a significant contribution to the improvement of epithelial sealing around implants. However, there is currently no optimal MSC delivery biomaterial for clinical application in peri-implant epithelium (PIE) integration. In this study, we show that injectable photo-cross-linkable porous gelatin methacryloyl (GelMA)/silk fibroin glycidyl methacrylate (SilMA) hydrogels encapsulating gingival tissue-derived MSCs (GMSCs) are a simple and practical approach for re-epithelization applications. The hydrogels played a prominent role in supporting the proliferation, survival, and spread of GMSCs. Moreover, it was found that GMSCs-laden Porous GelMA/SilMA hydrogels could significantly upregulate the hemidesmosomes (HDs)-related genes and proteins expression and promote M2 polarization while inhibiting M1 polarization in vitro. Based on a rat model of early implant placement, application of the MSC-loaded hydrogels could enhance the protein expression of LAMA3 and BP180 (COL17A1) at the implant-PIE interface and reduce horseradish peroxidase (HRP) penetration between the implants and PIE. Noticeably, hydrogel-based MSC therapy contributed to augmenting M2 macrophage infiltration at two time points in the gingival connective tissue around implants. These findings demonstrated that GMSCs-laden Porous GelMA/SilMA hydrogels could facilitate epithelial sealing around implants and M2-polarized macrophages and may be a novel and facile therapeutic strategy for implant-PIE integration. STATEMENT OF SIGNIFICANCE: In the case of poor integration between the implant and gingival epithelium, peri-implantitis can develop, which is one of the main causes of implant failure. While stem cell therapy has tremendous potential for addressing this issue, poor cell survival and engraftment compromise the effectiveness of the therapy. Due to the excellent modifiable and tunable properties of gelatin and silk fibroin, injectable photo-cross-linkable porous hydrogels were developed using gelatin methacryloyl (GelMA) and silk fibroin glycidyl methacrylate (SilMA) as delivery vehicles for gingiva-derived MSCs (GMSCs). Porous GelMA/SilMA not only enhanced the proliferation and viability of GMSCs but also promoted their immunomodulatory capability for favorable epithelial sealing around implants. Overall, GMSCs-seeded porous hydrogels could be promising strategies for re-epithelization treatment.

Construction of Smart Biomaterials for Promoting Diabetic Wound Healing

Diabetes mellitus is a complicated metabolic disease that has become one of the fastest-growing health crises in modern society. Diabetic patients may suffer from various complications, and diabetic foot is one of them. It can lead to increased rates of lower-extremity amputation and mortality, even seriously threatening the life and health of patients. Because its healing process is affected by various factors, its management and treatment are very challenging. To address these problems, smart biomaterials have been developed to expedite diabetic wound closure and improve treatment outcomes. This review begins with a discussion of the basic mechanisms of wound recovery and the limitations of current dressings used for diabetic wound healing. Then, the categories and characteristics of the smart biomaterial scaffolds, which can be utilized as a delivery system for drugs with anti-inflammatory activity, bioactive agency, and antibacterial nanoparticles for diabetic wound treatment were described. In addition, it can act as a responsive system to the stimulus of the pH, reactive oxygen species, and glucose concentration from the wound microenvironment. These results show that smart biomaterials have an enormous perspective for the treatment of diabetic wounds in all stages of healing. Finally, the advantages of the construction of smart biomaterials are summarized, and possible new strategies for the clinical management of diabetic wounds are proposed.