Mussel-Inspired Electroactive and Antioxidative Scaffolds with Incorporation of Polydopamine-Reduced Graphene Oxide for Enhancing Skin Wound Healing

Tissue-adhesive, silk-based conductive hydrogel with high stretchable, transparent, healable and degradable properties for real-time, precise monitoring of tissue motions and electrocardiogram under sweaty condition

Developing bioelectronic sensors with exceptional physicochemical properties, such as strong adhesion to wet biological tissues, high mechanical strength and stretchability, transparency, self-healing ability, biocompatibility, and degradability remains a significant challenge in meeting the complex requirements of monitoring biological tissues. In this study, a novel silk fibroin/polyacrylamide/ferric ion (PAM-SF/Fe3+) double network hydrogel was developed by a self-assembly cross-linking strategy to address this challenge. Benefiting from the double network structure, reinforcement of random coils of SF, a large number of metal chelation and hydrogen bond interactions among SF, PAM, and Fe3+, the hydrogel demonstrates exceptional mechanical properties, including a maximum tensile strength of 71 kPa, elongation at break exceeding 1442 %, compressive stress over 0.66 MPa, Young's modulus of approximately 10 kPa, light transmittance of about 90 %, instant robust adhesion to various wet biological tissues even underwater, and excellent self-healing capability at room temperature. To the best of our knowledge, this is the highest stretchability and mechanical strength among the reported silk-based conductive hydrogels while simultaneously achieving adhesive performance on wet biological tissues. Additionally, the PAM-SF/Fe3+ hydrogel also exhibits good biocompatibility and degradability, enabling direct adhesion to wet biological tissue surfaces, such as pig lung and rat bladder, for real-time and reliable monitoring of their contractile movements. Furthermore, it serves as flexible conductive gel electrodes for long-term continuous monitoring of ECG signals under sweaty conditions and displays promising applications in implantable sensors, wearable devices, and personal healthcare and human-machine interfaces.

Combined treatment strategy of hydrogel dressing and physiotherapy for rapid wound healing

Wound care for open wounds is essential for reducing pain, protecting open wounds, speeding up the healing process and avoiding scar formation. Among the various three-dimensional (3D) carrier biomaterials such as films, sponges, and hydrogels, hydrogels are chemically and physically most similar to the natural extracellular matrix (ECM). Meanwhile, hydrogels are also common 3D carriers that can be efficiently loaded with drugs or cells. In addition, it forms a protective barrier on the wound surface to prevent secondary external infections and has the effect of directing skin cell expansion, tissue infiltration, and wound closure. However, the role of functional drugs in wound healing also faces a number of issues such as resistance, dosage, activity, and stability; therefore, a richer array of therapies is needed for wound repair and other areas of development. Physiotherapy, also known as nonpharmacological therapy, is a commonly used clinical treatment. Recently, more and more physiotherapy have been used for wound repair due to their high efficiency and low irritation. In recent reports, many researchers have tended to use hydrogel dressings in combination with physiotherapy, and this combination therapy is beneficial because it can both protect the wound microenvironment and accelerates wound healing. Therefore, this paper reviews the combined use of hydrogel dressings and physiotherapy in wound healing. We present the characteristics of hydrogel and physiotherapy and focus on the progress and problems of these two combined therapies in recent years.

MXenes in the application of diabetic foot: mechanisms, therapeutic implications and future perspectives

Diabetic foot represents a significant healthcare challenge, accounting for a substantial portion of diabetes-related hospitalizations and amputations globally. The complexity of diabetic foot management stems from the interplay of poor glycemic control, neuropathy, and peripheral vascular disease, which hinder wound healing processes. The high incidence, recurrence, and amputation rates associated with diabetic foot underscore the urgency for innovative treatment strategies. Recent advancements in nanotechnology, particularly the emergence of MXenes (two-dimensional transition metal carbides and/or nitrides), have shown promising potential in addressing these challenges by offering unique physicochemical and biological properties suitable for various biomedical applications. It is a novel potential strategy for diabetic foot wound healing in the future. This review comprehensively summarizes current knowledge, unique characteristics, and underlying mechanisms of MXenes in the context of diabetic foot management. Additionally, we propose the potential application of MXenes-based therapeutic strategies in diabetes foot. Furthermore, we also provide an overview of their current challenges and the future perspectives in related fields of diabetic wound healing.

Mussel-Inspired MXene/Antimicrobial Peptide-Integrated Photosensitive Poly(vinyl alcohol)-Based Hydrogel with Antibacterial, Anti-Inflammatory, and Electroactive Properties for Accelerated Wound Healing

Backgrounds: The buildup of reactive oxygen species (ROS) in infected wounds triggers an excessive inflammatory response, while the overuse of antibiotics has contributed to increased bacterial resistance. Therefore, developing wound dressings that effectively eliminate ROS and inhibit bacterial growth is crucial. Methods: Inspired by mussel-derived proteins, we developed a polydopamine (PDA)-grafted MXene (PDA@MXene) and 3,4-dihydroxyphenylalanine-PonG1 (DOPA-PonG1)-modified photosensitive poly(vinyl alcohol) (PVA) hydrogel as a wound dressing. PDA@MXene was synthesized through dopamine self-polymerization on the MXene surface, while tyrosine hydroxylation was used to introduce DOPA into the antibacterial peptide ponericin G1 (PonG1). The hydrogel and its components were characterized, and their morphology was examined. The hydrogel's hemostatic ability, mechanical properties, and conductivity were evaluated. In vitro studies systematically evaluated antioxidative effects, antibacterial activity, biocompatibility, and expression of tissue regeneration-related factors. An infected full-thickness skin defect model was established in vivo, and different hydrogel treatments were applied. The wound-healing rate was then measured, followed by histological analysis using hematoxylin and eosin, Masson, Sirius Red, and immunofluorescence staining to investigate the healing mechanism. Results: The DOPA sequence enhanced PonG1 stability on the hydrogel surface, leading to sustained antibacterial ability. PDA@MXene significantly improved the hydrogel's conductivity and mechanical strength. Notably, the combined effects of DOPA-PonG1 and PDA@MXene contributed to enhanced antibacterial and ROS-scavenging properties. In vivo findings demonstrated that the DOPA-PonG1/PDA@MXene/PVA hydrogel accelerated infected wound healing by promoting angiogenesis and collagen deposition while reducing excessive inflammation. This study presents an innovative approach for treating infected wound defects and holds promise for clinical applications.

Macro/nano topological modification of a silk fibroin mesh with mimicked extracellular matrix structure and excellent biocompatibility

Synthetic surgical meshes have been widely used for repairing hernias, but their performance, such as nonabsorbability and insufficient mechanical strength, requires further improvement due to postsurgical complications, including chronic pain and inflammation. In this work, naturally derived and bioresorbable silk fibroin meshes (SFM) with three knit patterns were optimized and modified by a combination of regenerated silk fibroin (RSF) and polydopamine (PDA), to endow SFM with a mimicked extracellular matrix (ECM) structure and excellent biocompatibility. Our study confirmed that the modified meshes (SFM@PDA-RSF) exhibited ECM-like structure and good structural stability. Tensile testing results revealed that the SFM substrate played a dominant role in mechanical properties, and SFM@PDA-RSF showed high tensile strength (49.58 N cm-1 transversely, 68.42 N cm-1 longitudinally), which could afford sufficient mechanical support for abdominal wall hernia (AWH) repair (16 N cm-1). Moreover, SFM@PDA-RSF was found to be significantly antioxidant, non-hemolytic, and favorable for cell adhesion and growth, showing great potential for effective hernia repair.

Polydopamine-modified hydroxyapatite and manganese tetroxide nanozyme incorporated gelatin methacryloyl hydrogel: A multifunctional platform for anti-bacteria, immunomodulation, angiogenesis, and enhanced regeneration in infected wounds

Intensive inflammation induced via bacterial infection seriously disturbs the immune-microenvironment and compromise the neovascularization in the skin wound. On the basis of reducing bacterial infections, alleviating inflammatory response and rebuild the crosstalk between macrophages and vascular endothelial cell (VEC) serve as the key strategy for facilitating infected wound healing. Herein, manganese tetroxide (Mn3O4) nanozymes and polydopamine-coated hydroxyapatite (PHA) nanoparticles were loaded on the gelatin methacryloyl (GelMA) hydrogel, which was subsequently crosslinked by the UV light to construct a multifunctional hydrogel wound dressing GelMA-PHA-Mn3O4 with excellent anti-bacterial, immuno-regulation and angiogenic properties. Triggered by near infrared (NIR), PHA exhibited photothermal effect and effectively eradicated Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) biofilm. On the other hand, Mn3O4 nanozymes in hydrogel exhibit desirable reactive oxygen species (ROS) scavenging capacity due to the redox cycle between Mn2+ and Mn3+, which successfully transform the LPS-induced macrophage phenotype from pro-inflammation M1 to anti-inflammation M2. Notably, the interaction between macrophages and VECs was subsequently reconstructed and exhibited an evident pro-angiogenic phenomenon along with the improvement of local immuno-microenvironment. In vivo study further verified that the GelMA-PHA-Mn3O4 hydrogel combined with NIR irradiation could accelerate the healing of infected wound through the prominent anti-bacterial and immuno-regulation effect. The collagen deposition and formation of blood vessel in the wound were active. Above, this study demonstrated that the GelMA-PHA-Mn3O4 hydrogel represents a promising approach for managing infected wounds, with an anticipated prospect in clinical application.

Bacterial microenvironment-responsive antibacterial, adhesive, and injectable oxidized dextran-based hydrogel for chronic diabetic wound healing

Diabetic wounds are highly susceptible to bacterial infections, often resulting in chronic wounds that pose a substantial challenge to clinical treatment. Furthermore, the irregular shapes of these wounds limit the effectiveness of conventional dressings. Therefore, development of a new type of antibacterial dressing that can accommodate various wound shapes is urgently required. In this study, we designed injectable hydrogels with bacterial microenvironment-responsive antibacterial, adhesive, and antioxidant properties. These hydrogels were developed by incorporating polydopamine nanoparticles (PDA NPs) into a gelatin/oxidized dextran (Gel-oDex) network crosslinked via dynamic Schiff base reactions. Notably, the Gel-oDex-PDA-PHMB hydrogel demonstrated strong antibacterial efficacy against S. aureus, E. coli, and MRSA (all exceeding 99%), with PHMB-release experiments confirming its responsiveness to the bacterial microenvironment. Additionally, the hydrogel exhibited significant antioxidant activity, as evidenced by the DPPH radical scavenging assays. With good biocompatibility, the Gel-oDex-PDA-PHMB hydrogel also demonstrated effectiveness in killing bacteria and promoting the regeneration and functional reconstruction of skin tissue in bacteria-infected diabetic rats.

A biomimetic nanofiber composite hydrogel with tissue adhesion, self-healing and antibacterial ability for infected wound healing

Skin injuries represent a significant clinical challenge, as conventional dressings frequently induce secondary trauma and microbial infiltration due to suboptimal barrier properties, ultimately delaying tissue repair. Ideal wound dressings should not only replicate the structure of native skin tissue but also create an environment conducive to cell viability. In this study, an injectable nanofiber composite self-healing hydrogel was developed for treating infected wounds. The antimicrobial properties of the hydrogel were achieved through the adsorption of branched polyethyleneimine (PEI) on gelatin fibers, while its self-healing capabilities were enhanced via Schiff base reactions and its tissue adhesion was strengthened by the incorporation of dopamine. Results demonstrated that the hydrogel exhibited strong biocompatibility and antimicrobial activity, promoted macrophage polarization towards the M2 phenotype, effectively suppressed inflammation, and facilitated wound healing in an infected wound model. STATEMENT OF SIGNIFICANCE: Wound infections pose a significant clinical challenge, often impeding healing and, in severe cases, leading to ulceration or life-threatening complications. In this study, a gelatin nanofiber composite hydrogel (PGF@ALG/PLGA hydrogel) functionalized with branched polyethyleneimine (PEI) was developed to address infected wounds through a biomimetic structure and enhanced pro-healing properties. The gelatin nanofibers within the hydrogel matrix facilitated electrostatic immobilization of PEI, effectively mitigating its inherent cytotoxicity by restricting free cationic charge exposure while ensuring localized surface enrichment. The resulting hydrogel exhibited robust tissue adhesion and autonomous self-healing capability. In infected wound models, the PEI-modified nanofibers within PGF@ALG/PLGA hydrogels demonstrated obvious antibacterial efficacy and promoted macrophage polarization to the M2 phenotype, synergistically accelerating the transition from the inflammatory phase to tissue regeneration. These findings underscore the therapeutic potential of PGF@ALG/PLGA hydrogel as a multifunctional platform for managing chronic infected wounds.

A 3D-printed grid-like hyaluronic acid based hydrogel loaded with deferoxamine as wound dressing promotes diabetic wound healing

The rigid inflammatory microenvironment and impaired vascular regeneration capability are two core barriers for diabetic wound healing. As hydrogels have unique 3D porous networks and hydrophilic structure, which can facilitate oxygen exchange and function as a functional delivery system for loading cells and other biomolecules, hydrogels have clinical potentials for treating diabetic wounds. Here we developed a 3D-printed grid-like hydrogel composed of hyaluronic acid-based acrylamide (HA-AM), oxidized mannan oligosaccharide (OMOS), and deferoxamine (DFO). We demonstrated that the developed hydrogel (HA-AM/OMOS@DFO) exhibited favorable swelling, reasonable degradation time, good biocompatibility and structural support strength. Moreover, the HA-AM/OMOS@DFO hydrogel exerted antioxidative effects and inflammatory regulation functions. In addition, the loaded DFO effectively promoted vascular regeneration in the wound, which facilitated the healing of chronic diabetic wounds. Findings suggested the developed material has potential for clinical application in treating diabetic wounds.

An immunoregulation PLGA/Chitosan aligned nanofibers with polydopamine coupling basic fibroblast growth factor and ROS scavenging for peripheral nerve regeneration

The repair and functional recovery of long-segment peripheral nerve injuries are crucial in clinical settings. Nerve conduits are seen as promising alternatives to autologous nerve grafts, but their effectiveness is limited by the controlled delivery of bioactive factors and meeting various functional requirements during different stages of repair. This research developed multifunctional nerve conduits using electrospinning and polydopamine (PDA) coating techniques to integrate bioactive substances. Chitosan-composite PLGA electrospun nerve conduits demonstrated exceptional mechanical properties and biocompatibility. Nanofibers with specific topological structures effectively promoted oriented cell growth. The PDA coating provided ROS scavenging and immune modulation functions. The bFGF growth factor attached to the PDA coating facilitated sustained release, enhancing Schwann cell functionality and stimulating neurite outgrowth. In a rat sciatic nerve defect model with a 10 mm gap, PLGA/CS-PDA-bFGF nerve conduits showed a positive impact on nerve regeneration and functional recovery. Consequently, nerve conduits with multiple functions modified with PDA-coated bioactive molecules are poised to be excellent materials for mending peripheral nerve injuries.

Antimicrobial Phenolic Materials: From Assembly to Function

Infectious diseases pose considerable challenges to public health, particularly with the rise of multidrug-resistant pathogens that globally cause high mortality rates. These pathogens can persist on surfaces and spread in public and healthcare settings. Advances have been made in developing antimicrobial materials to reduce the transmission of pathogens, including materials composed of naturally sourced polyphenols and their derivatives, which exhibit antimicrobial potency, broad-spectrum activity, and a lower likelihood of promoting resistance. This review provides an overview of recent advances in the fabrication of antimicrobial phenolic biomaterials, where natural phenolic compounds act as active antimicrobial agents or encapsulate other antimicrobial agents (e.g., metal ions, antimicrobial peptides, natural biopolymers). Various forms of phenolic biomaterials synthesized through these two strategies, including antimicrobial particles, capsules, hydrogels, and coatings, are summarized, with a focus on their application in wound healing, bone repair and regeneration, oral health, and antimicrobial coatings for medical devices. The potential of these advanced phenolic biomaterials provides a promising therapeutic approach for combating antimicrobial-resistant infections and reducing microbial transmission.

A novel skin-like patch based on 3D hydrogel nanocomposite of Polydopamine/TiO2 nanoparticles and Ag quantum dots accelerates diabetic wound healing compared to stem cell therapy

Despite the advances in the development of therapeutic wearable wound-healing patches, lack self-healing properties and strong adhesion to diabetic skin, hindering their effectiveness. We propose a unique, wearable patch made from a 3D organo-hydrogel nanocomposite containing polydopamine, titanium dioxide nanoparticles, and silver quantum dots (PDA-TiO2@Ag). The designed patch exhibits ultra-stretchable, exceptional-self-healing, self-adhesive, ensuring conformal contact with the skin even during movement. Our patch demonstrated potent antibacterial activity and significantly accelerated wound healing with a high wound closure rate of 99.2 % after 7 days. Remarkably, it enhanced diabetic skin wound healing compared to that achieved by adipose-derived stem cell (ADSC) therapy in a study involving 30 adult male albino rats. Microscopic analysis highlights the promising hierarchical architecture structure of the patch for wound healing applications, suggesting its potential to create a favorable environment for healing and provide long-lasting benefits. Histopathological analysis and immunohistochemical staining revealed faster healing and enhanced cellular response in the patch-treated group compared to both stem cell and control groups. Notably, the patch promoted complete re-epithelization and a significant increase in vascular endothelial growth factor (VEGF) expression on day 7, indicating improved angiogenesis. This self-healing, multifunctional patch offers a promising alternative to stem cell therapy for accelerating diabetic wound healing, showcasing its potential for clinical translation. The combination of durability, biocompatibility, and antibacterial properties makes the patch a promising candidate for advanced wound management and offering faster, more complete restoration than other approaches.

Preparation of Tragopogon graminifolius-loaded electrospun nanofibers and evaluating its wound healing activity in a rat model of skin scar

Background

Growing reports are dedicated to providing novel agents for wound healing with fewer adverse effects and higher efficacy. The efficacy of nanofibers composed of polyvinyl alcohol (PVA)/polyethylene oxide (PEO)/chitosan (CS) in promoting wound healing can be attributed to their ability to stimulate collagen production. Among the herbal agents with fewer adverse effects, Tragopogon graminifolius DC. [Asteraceae] (TG), also called "Sheng" in traditional Iranian medicine, is one of the most efficacious plants for treating various skin injuries due to its several pharmacological and biological effects like anti-inflammatory and antioxidant properties.

Purpose

In the present study, our objective was to assess the wound-healing activity of PVA/PEO/CS nanofibers containing TG in a rat model of excision wound repair.

Methods

Synthesized nanofibers from PVA, PEO, and CS were done by the electrospinning method and confirmed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR). The release tests of nanofibers were assessed through the UV-visible method at different time intervals, which were conducted for about 60 h. To evaluate the wound healing effects, rats were divided into four distinct groups, including negative control (untreated), phenytoin cream (as positive control), polymer (PVA/PEO/CS), and drug (nanofiber-containing 50% of TG extract; named PVA/PEO/CS/TG) groups. All treatments were administered topically once daily for 14 days. Wound size changes were investigated in different time intervals. On the 15th day, nitrite and catalase serum levels were measured. Furthermore, samples of skin tissue were extracted and subjected to histopathological analysis.

Results

PVA/PEO/CS nanofibers containing 1.2 g of PVA, 0.3 g of PEO, and 0.8 g of CS, along with 50% of TG extract (PVA/PEO/CS/TG) at 17 kV were selected based on its favorable morphology and uniform quality. PVA/PEO/CS/TG represented a notable reduction in wound sizes. Moreover, in histopathological analysis, PVA/PEO/CS/TG showed a lower presence of inflammatory cells, higher density of dermis collagen fibers, and better regeneration of the epidemic layer. In addition, PVA/PEO/CS/TG elevated plasma antioxidant capacity via increasing catalase while reducing nitrite levels.

Conclusion

PVA/PEO/CS/TG is a promising wound dressing nanofiber with antioxidant and tissue regeneration potential. These results encourage further studies for the development of TG nanofibers as promising agents in treating and accelerating the process of excision wound repair.

Sustained Release of Curcumin from Cur-LPs Loaded Adaptive Injectable Self-Healing Hydrogels

Biological tissue defects are typically characterized by various shaped defects, and they are prone to inflammation and the excessive accumulation of reactive oxygen species. Therefore, it is still urgent to develop functional materials which can fully occupy and adhere to irregularly shaped defects by injection and promote the tissue repair process using antioxidant and anti-inflammatory mechanisms. Herein, in this work, phenylboronic acid modified oxidized hyaluronic acid (OHAPBA) was synthesized and dynamically crosslinked with catechol group modified glycol chitosan (GCHCA) and guar gum (GG) into a hydrogel loaded with curcumin liposomes (Cur-LPs) which were relatively uniformly distributed around 180 nm. The hydrogel possessed rapid gelation within 30 s, outstanding injectability and tissue-adaptive properties with self-healing properties, and the ability to adhere to biological tissues and adapt to tissue movement. Moreover, good biocompatibility and higher DPPH scavenging efficiency were illustrated in the hydrogel. And a more sustainable release of curcumin from Cur-LPs-loaded hydrogels, which could last for 10 days, was achieved to improve the bioavailability of curcumin. Finally, they might be injected to fully occupy and adhere to irregularly shaped defects and promote the tissue repair process by antioxidant mechanisms and the sustained release of curcumin for anti-inflammation. And the hydrogel would have potential application as candidates in tissue defect repair.

Natural polysaccharides combined with mussel-inspired adhesion for multifunctional hydrogels in wound hemostasis and healing: A review

As naturally derived macromolecular polymers, polysaccharides have garnered significant attention in recent years as promising candidates for fabricating multifunctional hydrogels, particularly for wound healing applications, owing to their inherent biocompatibility, biodegradability, and structural diversity. However, the inherently weak skin adhesion of natural polysaccharide hydrogels has motivated the exploration of mussel-inspired catechol-based adhesion strategies to overcome this limitation. Incorporating mussel-inspired modifications into natural polysaccharides can imbue them with unique properties such as enhanced adhesion, antioxidant activity, antibacterial properties, and chelation capabilities, considerably broadening their potential for wound hemostasis and healing applications. This review comprehensively overviews recent advances in mussel-inspired polysaccharide hydrogels, focusing on the combination of natural polysaccharides, including chitosan, alginate, hyaluronic acid, cellulose, and dextran, with mussel-inspired catechol. We delve into their fabrication strategies and highlight their promising biomedical applications, with a particular emphasis on wound hemostasis and diverse wound healing processes. Mussel-inspired modification strategies for polysaccharide hydrogels are expected to remain a focal point within the fields of wound hemostasis and healing, paving the way for more impactful research endeavors.

Intelligent Hydrogel with Physiologically Dependent Capacities of Photothermal Conversion and Nanocatalytic Medicine to Integratively Inhibit Bacteria and Inflammation for On-Demand Treatment of Infected Wound

Although chemodynamic therapy (CDT) and photothermal therapy (PTT) based on a variety of nanoparticles have been developed to achieve effective anti-bacterial therapy, the limited therapeutic efficiency of CDT alone, as well as the undifferentiated damage of PTT to both bacteria and surrounding healthy tissue are still challenges for their clinical application of infected wounds treatments. In addition, during the CDT and PTT-mediated antimicrobial processes, the endogenous macrophages would be easily converted to pro-inflammatory macrophages (M1 phenotype) under local ROS and hyperthermia to promote inflammation, resulting in unexpected suppression of tissue regeneration and possible wound deterioration. To address these problems, a biodegradable sodium alginate/hyaluronic acid hydrogel loaded with functional CeO2-Au nano-alloy (AO@ACP) is fabricated to not only achieve precise and efficient antibacterial activity through infection-environment dependent photothermal-chemodynamic therapy but also rapidly eliminate the excess reactive oxygens (ROS) in the M1 type macrophage at the infected area to induce their polarization to M2 type for significant inhibition of inflammation and remarkable enhancement of tissue regeneration, hopefully developing an effective strategy to treat infected wound.

Biomimetic composite gelatin methacryloyl hydrogels for improving survival and osteogenesis of human adipose-derived stem cells in 3D microenvironment

Gelatin methacryloyl (GelMA) hydrogels are used for stem cell encapsulation in bone tissue engineering due to their fast and stable photo-crosslinking. However, cell viability and ability to induce osteogenesis are reduced by reactive oxygen species (ROS) produced during the crosslinking reaction. In this study, we developed biomimetic nanoparticles (TMNs) by combining tannic acid (TA) and simulated body fluid (SBF) minerals, and used them to synthesize GelMA-based composite hydrogels for addressing those limitations. The optimal concentrations of TA and SBF were investigated to create nanoparticles that can effectively scavenge ROS and induce osteogenesis. The incorporation of TMNs into composite hydrogels (G-TMN) significantly enhanced the survival and proliferation of encapsulated human adipose-derived stem cells (hADSCs) by providing resistance to oxidative conditions. In addition, the ions that were released, such as Ca2+ and PO4 3-, stimulated stem cell differentiation into bone cells. The hADSCs encapsulated in G-TMN had 2.0 ± 0.8-fold greater viability and 1.3 ± 1.8 times greater calcium deposition than those encapsulated in the hydrogel without nanoparticles. Furthermore, the in vivo transplantation of G-TMN into a subcutaneous mouse model demonstrated the rapid degradation of the gel-network while retaining the osteoinductive particles and cells in the transplanted area. The increased cellular activity observed in our multifunctional composite hydrogel can serve as a foundation for novel and effective therapies for bone deformities.

New Composite Materials Based on PVA, PVP, CS, and PDA

In this work, new materials based on the blends of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), chitosan (CS), and polydopamine (PDA) have been prepared. Fourier Transform Infrared Spectra have been conducted to verify the presence of individual components in the composite materials. EDX elemental analysis showed a clear view of the element's presence in the composite materials, with the maximum values for carbon and oxygen. Atomic force microscopy (AFM) was used to observe the surface topography and measure the surface roughness. In the case of the individual polymers, CS presented the higher value of surface roughness (Rq = 3.92 nm and Ra = 3.02 nm), and surface roughness was found to be the lowest in the case of polyvinyl pyrrolidone (PVP), and it was with values (Rq = 2.34 nm and Ra = 0.95 nm). PVA films presented the surface roughness, which was with the value (Rq = 3.38 nm and Ra = 2.11 nm). In the case of composites, surface roughness was highest for the composite based on PVA, PVP, and CS, which presented the value (Rq = 11.91 nm and Ra = 8.71 nm). After the addition of polydopamine to the polymeric composite of PVA, PVP, and CS, a reduction in the surface roughness was observed (Rq = 7.49 nm and Ra = 5.15 nm). The surface roughness for composite materials was higher than that of the individual polymers. The addition of PDA to polymeric composite (PVA/PVP/CS) led to a decrease in Young's modulus. The elongation percentage of the polymeric films based on the PVA/PVP/CS/PDA blend was higher than that of the blend without PDA (9.80% vs. 5.68% for the polymeric composite PVA/PVP/CS). The surface of polymeric films was hydrophilic. The results from the MTT assay showed that all tested specimens are non-toxic, and it was manifested by a significant increase in the viability of L929 cells compared with control cells. However, additional studies are required to check the biocompatibility of tested samples.

A novel multifunctional nanocomposite hydrogel orchestrates the macrophage reprogramming-osteogenesis crosstalk to boost bone defect repair

Repairing bone defects is a complex cascade reaction process, as immune system regulation, vascular growth, and osteogenic differentiation are essential. Thus, developing a tissue-engineered biomaterial that caters to the complex healing process of bone regeneration remains a major clinical challenge. In the study, Ca2+-TA-rGO (CTAG)/GelMA hydrogels were synthesized by binding Ca2+ using metal chelation to graphene oxide (GO) nanosheets reduced by tannic acid (TA-rGO) and doping them into gelatin methacrylate (GelMA) hydrogels. TA and rGO exhibited biocompatibility and immunomodulatory properties in this composite, while Ca2+ promoted bone formation and angiogenesis. This novel nanocomposite hydrogel demonstrated good mechanical properties, degradability, and conductivity, and it could achieve slow Ca2+ release during bone regeneration. Both in vitro and in vivo experiments revealed that CTAG/GelMA hydrogel modulated macrophage reprogramming and induced a shift from macrophages to healing-promoting M2 macrophages during the inflammatory phase, promoted vascular neovascularization, and facilitated osteoblast differentiation during bone formation. Moreover, CTAG/GelMA hydrogel could downregulate the NF-κB signaling pathway, offering new insights into regulating macrophage reprogramming-osteogenic crosstalk. Conclusively, this novel multifunctional nanocomposite hydrogel provides a multistage treatment for bone and orchestrates macrophage reprogramming-osteogenic crosstalk to boost bone repair.

Graphene-Based Wound Dressings for Wound Healing: Mechanism, Technical Analysis, and Application Status

The development of novel wound dressings is critical in medical care. Graphene and its derivatives possess excellent biomedical properties, making them highly suitable for various applications in medical dressings. This review provides a comprehensive technical analysis and the current application status of graphene-based medical dressings. Initially, we discuss the chemical structure and the fabrication method of graphene and its derivatives. We then provide a detailed summary of the mechanisms by which graphene materials promote wound repair across the four stages of wound healing. Subsequently, we categorize the types of graphene-based wound dressings and analyze corresponding characteristics. Finally, we analyze the challenges encountered at present and propose solutions regarding future development trends. This paper aims to serve as a reference for further research in skin tissue engineering and the development of innovative graphene-based medical dressings.

Inclusion of Reduced Graphene Oxide to Silk Fibroin Hydrogels Improve the Conductive, Swelling and Wound Healing Capacity

Developing dressing for wound dressings represents a significant challenge for the scientific community. In this study, a conductive hydrogel was synthesized to promote the wound‐healing process. This hydrogel is composed of silk fibroin (SF), reduced graphene oxide (rGO), and glycerol (G). The impact of modifying the SF:rGO ratio, and the G content (%), on the physicochemical and biological properties. The hydrogels were characterized using FT‐IR, SEM, XRD, TGA, swelling, mechanical resistance, and conductivity. The cytotoxicity of the materials and their wound‐healing capacity in human fibroblasts were also determined. Chemical analysis revealed that the gelation of SF occurs due to the formation of β sheet structures, which was confirmed by the shift from amide I to amide II. An Increase in the SF:rGO ratio favored swelling behavior, although increasing G reduced this effect. The swelling of the hydrogel followed a Fick diffusion mechanism. Furthermore, the increase in the SF:rGO ratio and the percentage G improved the conductivity of the materials. The hydrogels were found to be non‐cytotoxic to human fibroblasts, and those containing rGO exhibited superior wound healing capacity compared to the positive control cell culture medium. Therefore, SF:rGO hydrogels could be considered promising candidates for wound dressing.

Biological macromolecule-based hydrogels with antibacterial and antioxidant activities for wound dressing: A review

Because of the complex symptoms resulting from metabolic dysfunction in the wound microenvironment during bacterial infections, along with the necessity to combat free radicals, achieving prompt and thorough wound healing remains a significant medical challenge that has yet to be fully addressed. Moreover, the misuse of common antibiotics has contributed to the emergence of drug-resistant bacteria, underscoring the need for enhancements in the practical and commonly utilized approach to wound treatment. In this context, hydrogel dressings based on biological macromolecules with antibacterial and antioxidant properties present a promising new avenue for skin wound treatment due to their multifunctional characteristics. Despite the considerable potential of this innovative approach to wound care, comprehensive research on these multifunctional dressings is still insufficient. Consequently, the development of advanced biological macromolecule-based hydrogels, such as chitosan, alginate, cellulose, hyaluronic acid, and others, has been the primary focus of this study. These materials have been enriched with various antibacterial and antioxidant agents to confer multifunctional attributes for wound healing purposes. This review article aims to offer a comprehensive overview of the latest progress in this field, providing a critical theoretical basis for future advancements in the utilization of these advanced biological macromolecule-based hydrogels for wound healing.

MXene-coated piezoelectric poly-L-lactic acid membrane accelerates wound healing by biomimicking low-voltage electrical pulses

Electrical stimulation therapy is effective in promoting wound healing by rescuing the decreased endogenous electrical field, where self-powered and miniaturized devices such as nanogenerators become the emerging trends. While high-voltage and unidirectional electric field may pose thermal effect and damage to the skin, nanogenerators with lower voltages, pulsed or bidirectional currents, and less invasive electrodes are preferred. Herein, we construct a polydopamine (PDA)-modified poly-L-lactic acid (PLLA) /MXene (PDMP/MXene) nanofibrous composite membrane that generates piezoelectric voltages matching the transepithelial potential (TEP) to accelerate wound healing. PDA coating not only enhances the piezoelectricity of PLLA by dipole attraction and alignment, but also increases its hydrophilicity and facilitates subsequent MXene adhesion for electrical conductivity and stability in physiological environment. When applied as wound dressings in mice, the PDMP/MXene membranes act as a nanogenerators with reduced internal resistances and satisfactory piezoelectric performances that resemble bioelectric potentials (~10 mV) responding to physical activities. The membrane significantly accelerates wound closure by facilitating fibroblast migration, collagen deposition and angiogenesis, and suppressing the expression of inflammatory responses. This piezoelectric fibrous membrane therefore provides a convenient solution for speeding up wound healing by sustained low voltage mimicking bioelectricity, better cell affinity.

A review on the use of composites of a natural protein, silk fibroin with Mxene/carbonaceous materials in biomedical science

Silk fibroin (SF), a natural biodegradable and biocompatible protein, has garnered significant attention in biomedical applications due to its impressive properties, including excellent biocompatibility, biodegradability, and mechanical resilience. Nevertheless, its broader usage faces obstacles by its insufficient mechanical strength and electrical conductivity. In order to address these constraints, recent studies have concentrated on combining SF with cutting-edge nanomaterials like MXene and carbon-based materials. This review comprehensively examines the applications and potential of silk fibroin-MXene/carbon-based nanocomposites in biomedical fields. The unique properties of SF, MXene, and carbon-based materials are explored, emphasizing how their combination enhances mechanical strength, conductivity, and biocompatibility. These composites show substantial enhancements in performance for several biomedical applications by utilising the excellent conductivity and mechanical capabilities of MXene and carbonaceous elements. The innovative potential of these nanocomposites is highlighted by critically discussing key applications such as tissue engineering, drug delivery, and biosensing. In addition, the work discusses the latest research progress, difficulties, and future prospects in the sector, providing valuable insights into possible breakthroughs and uses. This review seeks to comprehensively analyse the existing information on silk fibroin-MXene/carbon based nanocomposites in healthcare.

Preparation of silk fibroin-derived hydrogels and applications in skin regeneration

Purpose

To compare different methods of preparing silk fibroin hydrogels, then summarize the applications of silk fibroin hydrogel-based scaffolds in skin regeneration and finally discuss about future prospects to inspire people interested in this field.

Methods

A narrative review of the relevant papers was conducted. Notably, for applications in skin regeneration, this review provides a categorized summary and discussion of studies from the past decade.

Results

Silk fibroin is a naturally occurring, biocompatible biomaterial that is easily producible. Thanks to its exceptional processability, silk fibroin has found diverse applications in skin regeneration. These applications encompass sponges, fiber fabrics, thin films, and hydrogels. Hydrogels, in particular, are noteworthy due to their water-containing network structure, closely resembling natural tissues. They provide a biomimetic three-dimensional growth environment for cells and have the capacity to incorporate growth factors. Consequently, there are abundant studies of silk fibroin hydrogel-based scaffolds in skin regeneration. Besides, some commercialized medical devices are also made of silk fibroin.

Conclusion

Silk fibroin hydrogel could be prepared with multiple methods and it is widely used in constructing scaffolds for efficient skin regeneration. In the future, silk fibroin hydrogel-based skin scaffolds could be more biomimetic and smart.

Polyphosphazene Microparticles with High Free Radical Scavenging Activity for Skin Photoprotection

Ultraviolet (UV) filters are the core ingredients in sunscreens and protect against UV-induced skin damage. Nevertheless, their safety and effectiveness have been questioned in terms of their poor photostability, skin penetration, and UV-induced generation of deleterious reactive oxygen species (ROS). Herein, an organic UV filter self-framed microparticle sunblock was exploited, in which quercetin (QC) and hexachlorocyclotriphosphazene (HCCP) were self-constructed into microparticles (HCCP-QC MPs) by facile precipitation polymerization without any carriers. HCCP-QC MPs could not only significantly extend the UV shielding range to the whole UV region but also remarkably reduce UV-induced ROS while avoiding direct skin contact and the resulting epidermal penetration of small-molecule QC. Meanwhile, HCCP-QC MPs possess a high QC-loading ability (697 mg g-1) by QC itself as the microparticles' building blocks. In addition, there is no leakage issue with small molecules due to its covalently cross-linked structure. In vitro and vivo experiments also demonstrated that the HCCP-QC MPs have excellent UV protection properties and effective ROS scavenging ability without toxicity. In summary, effective UV-shielding and ROS scavenging ability coupled with excellent biocompatibility and nonpenetration of small molecules make it a broad prospect in skin protection.

Chondroitin sulfate/silk fibroin hydrogel incorporating graphene oxide quantum dots with photothermal-effect promotes type H vessel-related wound healing

Chronic wounds with bacterial infection present formidable clinical challenges. In this study, a versatile hydrogel dressing with antibacterial and angiogenic activity composite of silk fibroin (SF), chondroitin sulfate (CS), and graphene oxide quantum dots (GOQDs) is fabricated. GOQDs@SF/CS (GSC) hydrogel is rapidly formed through the enzyme catalytic action of horseradish peroxidase. With the incorporation of GOQDs both gelation speed and mechanical properties have been enhanced, and the photothermal characteristics of GOQDs in GSC hydrogel enabled bacterial killing through photothermal treatment (PTT) at ∼51 °C. In vitro studies show that the GSC hydrogels demonstrate excellent antibacterial performance and induce type H vessel differentiation of endothelial cells via the activated ERK1/2 signaling pathway and upregulated SLIT3 expression. In vivo results show that the hydrogel significantly promotes type H vessels formation, which is related to the collagen deposition, epithelialization and, ultimately, accelerates the regeneration of infected skin defects. Collectively, this multifunctional GSC hydrogel, with dual action of antibacterial efficacy and angiogenesis promotion, emerges as an innovative skin dressing with the potential for advancing in infected wound healing.

An Antibacterial, Conductive Nanocomposite Hydrogel Coupled with Electrical Stimulation for Accelerated Wound Healing

Background

Electrical stimulation (ES) can effectively promote skin wound healing; however, single-electrode-based ES strategies are difficult to cover the entire wound area, and the effectiveness of ES is often limited by the inconsistent mechanical properties of the electrode and wound tissue. The above factors may lead to ES treatment is not ideal.

Methods

A multifunctional conductive hydrogel dressing containing methacrylated gelatin (GelMA), Ti3C2 and collagen binding antimicrobial peptides (V-Os) was developed to improve wound management. Ti3C2 was selected as the electrode component due to its excellent electrical conductivity, the modified antimicrobial peptide V-Os could replace traditional antibiotics to suppress bacterial infections, and GelMA hydrogel was used due to its clinical applicability in wound healing.

Results

The results showed that this new hydrogel dressing (GelMA@Ti3C2/V-Os) not only has excellent electrical conductivity and biocompatibility but also has a durable and efficient bactericidal effect. The modified antimicrobial peptides V-Os used were able to bind more closely to GelMA hydrogel to exert long-lasting antibacterial effects. The results of cell experiment showed that the GelMA@Ti3C2/V-Os hydrogel dressing could enhance the effect of current stimulation and significantly improve the migration, proliferation and tissue repair related genes expression of fibroblasts. In vitro experiments results showed that under ES, GelMA@Ti3C2/V-Os hydrogel dressing could promote re-epithelialization, enhance angiogenesis, mediate immune response and prevent wound infection.

Conclusion

This multifunctional nanocomposite hydrogel could provide new strategies for promoting infectious wound healing.

Silk-Based 3D Porous Scaffolds for Tissue Engineering

Silk fibroin, extracted from the silk of the Bombyx mori silkworm, stands out as a biomaterial due to its nontoxic nature, excellent biocompatibility, and adjustable biodegradability. Porous scaffolds, a type of biomaterial, are crucial for creating an optimal microenvironment that supports cell adhesion and proliferation, thereby playing an essential role in tissue remodeling and repair. Therefore, this review focuses on 3D porous silk fibroin-based scaffolds, first summarizing their preparation methods and then detailing their regenerative effects on bone, cartilage, tendon, vascular, neural, skin, hepatic, and tracheal epithelial tissue engineering in recent years.

Versatile dopamine-functionalized hyaluronic acid-recombinant human collagen hydrogel promoting diabetic wound healing via inflammation control and vascularization tissue regeneration

The management of chronic wounds in diabetes remains challenging due to the complexity of impaired wound healing, delayed healing, susceptibility to infection, and elevated risk of reopening, highlighting the need for effective chronic wound management with innovative approaches such as multifunctional hydrogels. Here, we have produced HA-DA@rhCol hydrogels consisting of dopamine-modified hyaluronic acid and recombinant human collagen type-III (rhCol) by oxidative coupling of the catechol group using the H2O2/HRP catalytic system. The post-reactive hydrogel has a good porous structure, swelling rate, reasonable degradation, rheological and mechanical properties, and the catechol group and dopamine impart to the hydrogel tissue adhesiveness, antioxidant capacity, and excellent photothermal effects leading to superior in vitro antimicrobial activity. In addition, the ability of rhCol to confer hydrogels to promote angiogenesis and wound repair has also been investigated. Cytotoxicity and hemolysis tests demonstrated the good biocompatibility of the hydrogel. Wound closure, collagen deposition and immunohistochemical examination confirmed the ability of the hydrogel to promote diabetic wound healing. In summary, the adhesive hemostatic antioxidative hydrogel with rhCol to promote wound healing in diabetic rat is an excellent chronic wound dressing.

Bioinspired, surfactant-free, dual-layer asymmetric structures based on polysaccharides, gelatin, and tannic acid for potential applications in biomedicine

The formation of dual-layer asymmetric porous structures in surfactant-based systems is significantly influenced by emulsions. Surfactants self-assemble to alter the conformational arrangement of polysaccharides, while gravity disrupts the initial uniformity of the established equilibrium droplet concentration gradient in the emulsion, thus achieving delamination. Specifically, high-speed rotation and non-instantaneous freezing allow the gelatin solution to form two different states of foam layers. The integrated dual-layer asymmetric porous structure, composed of polysaccharides and tannic acid, is constructed with gelatin as a skeleton and surfactant. This innovative approach eliminates the need to consider the toxicity of chemically synthesized surfactants and expands the concept of gelatin utilization. This intriguing structure exhibits a variety of desirable characteristics within 30 days (e.g., tailorable performance, ultrarapid antioxidant activity, efficient antibacterial activity, low differential blood clotting index, and good hemocompatibility and cytocompatibility), suggesting its potential as a valuable reference for applying hierarchical porous structures, thereby offering more formulation flexibility for biomaterials with adjustable properties.

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

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

Mussel-inspired electroactive, antibacterial and antioxidative composite membranes with incorporation of gold nanoparticles and antibacterial peptides for enhancing skin wound healing

Large skin wounds are one of the most important health problems in the world. Skin wound repair and tissue regeneration are complex processes involving many physiological signals, and effective wound healing remains an enormous clinical challenge. Therefore, there is an urgent need for a strategy to rapidly kill bacteria, promote cell proliferation and accelerate wound healing. At present, electrical stimulation (ES) is often used in the clinical treatment of skin wounds and can simulate the endogenous biological current of the body and accelerate the repair process of skin wounds. However, a single ES strategy has difficulty covering the entire wound area, which may lead to unsatisfactory therapeutic effects. To overcome this deficiency, it is essential to develop a collaborative treatment strategy that combines ES with other treatments. In this study, gold nanoparticles and antibacterial peptides (Os) were loaded on the surface of poly(lactic-co-glycolic acid) (PLGA) material through the reducibility and adhesion of polydopamine (PDA) and improved the electrical activity, anti-inflammatory, antibacterial and biocompatibility properties of the polymer material. At the same time, this composite membrane material (Os/Au-PDA@PLGA) combined with ES was used in wound therapy to improve the wound healing rate. The results show that the new wound repair material has good biocompatibility and can effectively promote cell proliferation and migration. Through the combined application of gold nanoparticles and antibacterial peptides Os, the polymer materials have more efficient bactericidal and antioxidant effects. The antibacterial experiment results showed that gold nanoparticles could further enhance the antibacterial activity of antibacterial peptides. Furthermore, the Os/Au-PDA@PLGA composite membrane has good hydrophilicity and electrical activity, which can provide a more favorable cell microenvironment for wound healing. In vivo studies using a full-thickness skin defect model in rats showed that the Os/Au-PDA@PLGA composite membrane had a better therapeutic effect than the pure PLGA material. More importantly, the combination of the Os/Au-PDA@PLGA composite with ES significantly accelerated the rate of vascularization and collagen deposition and promoted wound healing compared with non-ES controls. Therefore, the combination of the Au/Os-PDA@PLGA composite membrane with ES may provide a new strategy for the effective treatment of skin wounds.

ROS-scavenging materials for skin wound healing: advancements and applications

The intricate healing process of skin wounds includes a variety of cellular and molecular events. Wound healing heavily relies on reactive oxygen species (ROS), which are essential for controlling various processes, including inflammation, cell growth, angiogenesis, granulation, and the formation of extracellular matrix. Nevertheless, an overabundance of reactive oxygen species (ROS) caused by extended oxidative pressure may result in the postponement or failure of wound healing. It is crucial to comprehend the function of reactive oxygen species (ROS) and create biomaterials that efficiently eliminate ROS to enhance the healing process of skin wounds. In this study, a thorough examination is presented on the role of reactive oxygen species (ROS) in the process of wound healing, along with an exploration of the existing knowledge regarding biomaterials employed for ROS elimination. In addition, the article covers different techniques and substances used in the management of skin wound. The future prospects and clinical applications of enhanced biomaterials are also emphasized, highlighting the potential of biomaterials that scavenge active oxygen to promote skin repair. This article seeks to enhance the understanding of the complex processes of ROS in the healing of wounds and the application of ROS-scavenging materials. Its objective is to create novel strategies for effective treatment skin wounds.

Smart Responsive and Controlled-Release Hydrogels for Chronic Wound Treatment

Chronic wounds are a major health challenge that require new treatment strategies. Hydrogels are promising drug delivery systems for chronic wound healing because of their biocompatibility, hydration, and flexibility. However, conventional hydrogels cannot adapt to the dynamic and complex wound environment, which involves low pH, high levels of reactive oxygen species, and specific enzyme expression. Therefore, smart responsive hydrogels that can sense and respond to these stimuli are needed. Crucially, smart responsive hydrogels can modulate drug release and eliminate pathological factors by changing their properties or structures in response to internal or external stimuli, such as pH, enzymes, light, and electricity. These stimuli can also be used to trigger antibacterial responses, angiogenesis, and cell proliferation to enhance wound healing. In this review, we introduce the synthesis and principles of smart responsive hydrogels, describe their design and applications for chronic wound healing, and discuss their future development directions. We hope that this review will inspire the development of smart responsive hydrogels for chronic wound healing.

Extracellular Matrix-Mimetic Immunomodulatory Hydrogel for Accelerating Wound Healing

Macrophages play a crucial role in the complete processes of tissue repair and regeneration, and the activation of M2 polarization is an effective approach to provide a pro-regenerative immune microenvironment. Natural extracellular matrix (ECM) has the capability to modulate macrophage activities via its molecular, physical, and mechanical properties. Inspired by this, an ECM-mimetic hydrogel strategy to modulate macrophages via its dynamic structural characteristics and bioactive cell adhesion sites is proposed. The LZM-SC/SS hydrogel is in situ formed through the amidation reaction between lysozyme (LZM), 4-arm-PEG-SC, and 4-arm-PEG-SS, where LZM provides DGR tripeptide for cell adhesion, 4-arm-PEG-SS provides succinyl ester for dynamic hydrolysis, and 4-arm-PEG-SC balances the stability and dynamics of the network. In vitro and subcutaneous tests indicate the dynamic structural evolution and cell adhesion capacity promotes macrophage movement and M2 polarization synergistically. Comprehensive bioinformatic analysis further confirms the immunomodulatory ability, and reveals a significant correlation between M2 polarization and cell adhesion. A full-thickness wound model is employed to validate the induced M2 polarization, vessel development, and accelerated healing by LZM-SC/SS. This study represents a pioneering exploration of macrophage modulation by biomaterials' structures and components rather than drug or cytokines and provides new strategies to promote tissue repair and regeneration.

Multi-functional conductive hydrogels based on heparin-polydopamine complex reduced graphene oxide for epidermal sensing and chronic wound healing

Flexible hydrogel sensors have expanded the applications of electronic devices due to their suitable mechanical properties and excellent biocompatibility. However, conventionally synthesized reduced graphene oxide (rGO) encounters limitations in reduction degree and dispersion, restricting the conductivity of graphene hydrogels and impeding the development of high-sensitivity flexible sensors. Moreover, hydrogels are susceptible to inflammation and bacterial infections, jeopardizing sensor stability over time. Thus, the challenge persists in designing conductive hydrogels that encompass high sensitivity, antibacterial efficacy, and anti-oxidative capabilities. In this study, GO was modified and reduced via a heparin-polydopamine (Hep-PDA) complex, yielding well-reduced and uniformly dispersed Hep-PDA-rGO nanosheets. Consequently, a hydrogel utilizing Hep-PDA-rGO was synthesized, showcasing commendable conductivity (3.63 S/m) and sensor performance, effectively applied in real-time motion monitoring. Notably, the hydrogel's attributes extend to facilitating chronic diabetic wound healing. It maintained a suitable inflammatory environment credited to its potent antibacterial and antioxidative properties, while its inherent conductivity promoted angiogenesis. The multifunctional nature of this hydrogel highlight its potential not only as an epidermal sensor but also as a promising dressing candidate for chronic wound treatment.

Smart and versatile biomaterials for cutaneous wound healing

The global increase of cutaneous wounds imposes huge health and financial burdens on patients and society. Despite improved wound healing outcomes, conventional wound dressings are far from ideal, owing to the complex healing process. Smart wound dressings, which are sensitive to or interact with changes in wound condition or environment, have been proposed as appealing therapeutic platforms to effectively facilitate wound healing. In this review, the wound healing processes and features of existing biomaterials are firstly introduced, followed by summarizing the mechanisms of smart responsive materials. Afterwards, recent advances and designs in smart and versatile materials of extensive applications for cutaneous wound healing were submarined. Finally, clinical progresses, challenges and future perspectives of the smart wound dressing are discussed. Overall, by mapping the composition and intrinsic structure of smart responsive materials to their individual needs of cutaneous wounds, with particular attention to the responsive mechanisms, this review is promising to advance further progress in designing smart responsive materials for wounds and drive clinical translation.

Electrospun polyvinyl alcohol-chitosan dressing stimulates infected diabetic wound healing with combined reactive oxygen species scavenging and antibacterial abilities

Diabetic wounds (DW) are constantly challenged by excessive reactive oxygen species (ROS) accumulation and susceptibility to bacterial contamination. Therefore, the elimination of ROS in the immediate vicinity and the eradication of local bacteria are critical to stimulating the efficient healing of diabetic wounds. In the current study, we encapsulated mupirocin (MP) and cerium oxide nanoparticles (CeNPs) into a polyvinyl alcohol/chitosan (PVA/CS) polymer, and then a PVA/chitosan nanofiber membrane wound dressing was fabricated using electrostatic spinning, which is a simple and efficient method for fabricating membrane materials. The PVA/chitosan nanofiber dressing provided a controlled release of MP, which produced rapid and long-lasting bactericidal activity against both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. Simultaneously, the CeNPs embedded in the membrane exhibited the desired ROS scavenging capacity to maintain the local ROS at a normal physiological level. Moreover, the biocompatibility of the multifunctional dressing was evaluated both in vitro and in vivo. Taken together, PVA-CS-CeNPs-MP integrated the desirable features of a wound dressing, including rapid and broad-spectrum antimicrobial and ROS scavenging activities, easy application, and good biocompatibility. The results validated the effectiveness of our PVA/chitosan nanofiber dressing, highlighting its promising translational potential in the treatment of diabetic wounds.

Multifunctional chondroitin sulfate based hydrogels for promoting infected diabetic wounds healing by chemo-photothermal antibacterial and cytokine modulation

Diabetic foot (DF) is difficult to heal due to the formation of drug-resistant bacterial biofilms and dysregulation of the wound microenvironment. To solve this problem, multifunctional hydrogels were prepared by in situ or spraying with 3-aminophenylboronic acid modified oxidized chondroitin sulfate (APBA-g-OCS), polyvinyl alcohol (PVA) and black phosphorus/bismuth oxide/ε-polylysine (BP/Bi₂O₃/ε-PL) as precursors for promoting infected diabetic wounds healing. The hydrogels display multiple stimulus responsiveness, strong adhesion and rapid self-healing ability owing to the dynamic borate ester bonds, hydrogen bonds and π-π conjugation cross-link points, remain synergistic chemo-photothermal antibacterial effect and anti-biofilm formation ability due to the doping of BP/ Bi₂O₃/ε-PL into the hydrogel by dynamic imine bonds crosslinking and possess anti-oxidation and inflammatory chemokine adsorption ability attributing to the presence of APBA-g-OCS. Most importantly, as a result of the above functions, the hydrogels can not only respond to the wound microenvironment to conduct combined PTT and chemotherapy for efficient anti-inflammation, but also improve the wound microenvironment by scavenging ROS and regulating the expression of cytokines, thus further accelerating collagen deposition, promoting granulation tissue formation and angiogenesis, finally promoting the healing of infected wounds in diabetic rats.

Self-Assembled CNF/rGO/Tannin Composite: Study of the Physicochemical and Wound Healing Properties

In this study, a conductive composite material, based on graphene oxide (GO), nanocellulose (CNF), and tannins (TA) from pine bark, reduced using polydopamine (PDA), was developed for wound dressing. The amount of CNF and TA was varied in the composite material, and a complete characterization including SEM, FTIR, XRD, XPS, and TGA was performed. Additionally, the conductivity, mechanical properties, cytotoxicity, and in vitro wound healing of the materials were evaluated. A successful physical interaction between CNF, TA, and GO was achieved. Increasing CNF amount in the composite reduced the thermal properties, surface charge, and conductivity, but its strength, cytotoxicity, and wound healing performance were improved. The TA incorporation slightly reduced the cell viability and migration, which may be associated with the doses used and the extract's chemical composition. However, the in-vitro-obtained results demonstrated that these composite materials can be suitable for wound healing.

Graphene Oxide-Coated Patterned Silk Fibroin Films Promote Cell Adhesion and Induce Cardiomyogenic Differentiation of Human Mesenchymal Stem Cells

Cardiac tissue engineering is a promising strategy for the treatment of myocardial damage. Mesenchymal stem cells (MSCs) are extensively used in tissue engineering. However, transformation of MSCs into cardiac myocytes is still a challenge. Furthermore, weak adhesion of MSCs to substrates often results in poor cell viability. Here, we designed a composite matrix based on silk fibroin (SF) and graphene oxide (GO) for improving the cell adhesion and directing the differentiation of MSCs into cardiac myocytes. Specifically, patterned SF films were first produced by soft lithographic. After being treated by air plasma, GO nanosheets could be successfully coated on the patterned SF films to construct the desired matrix (P-GSF). The resultant P-GSF films presented a nano-topographic surface characterized by linear grooves interlaced with GO ridges. The P-GSF films exhibited high protein absorption and suitable mechanical strength. Furthermore, the P-GSF films accelerated the early cell adhesion and directed the growth orientation of MSCs. RT-PCR results and immunofluorescence imaging demonstrated that the P-GSF films significantly improved the cardiomyogenic differentiation of MSCs. This work indicates that patterned SF films coated with GO are promising matrix in the field of myocardial repair tissue engineering.

Rosmarinic Acid-Grafted Dextran/Gelatin Hydrogel as a Wound Dressing with Improved Properties: Strong Tissue Adhesion, Antibacterial, Antioxidant and Anti-Inflammatory

Designing a strong tissue adhesive and multifunctional hydrogel dressing for various skin injuries is still a significant challenge. Based on the bioactive activities of rosmarinic acid (RA) and its catechol structure being similar to dopamine, RA-grafted dextran/gelatin hydrogel (ODex-AG-RA) was designed and systemically characterized in this study. The ODex-AG-RA hydrogel exhibited excellent physicochemical properties, including fast gelation time (61.6 ± 2.8 s), strong adhesive strength (27.30 ± 2.02 kPa) and enhanced mechanical properties (1.31 × 10⁴ Pa of G'). The examination of hemolysis and co-culturing with L929 cells showed the strong in vitro biocompatibility of ODex-AG-RA hydrogels. The ODex-AG-RA hydrogels exhibited a 100% mortality rate against S. aureus and at least 89.7% against E. coli in vitro. In vivo evaluation for efficacy in skin wound healing was carried out in a rat model of full-thickness skindefect. The amount of collagen deposition and CD31 on wounds in the two ODex-AG-RA-1 groups on day 14 was 4.3 times and 2.3 times of that in the control group, respectively. Furthermore, the mechanism of ODex-AG-RA-1 for promoting wound healing was proved to be related to its anti-inflammatory properties by adjusting the expression of inflammatory cytokines (TNF-α and CD163) and reducing the level of oxidative stress (MDA and H₂O₂). Overall, this study demonstrated the wound-healing efficacy of RA-grafted hydrogels for the first time. ODex-AG-RA-1 hydrogel, due to its adhesive, anti-inflammatory, antibacterial and antioxidative activities, was a promising candidate as a wound dressing.

Gene liposome nanocomplex-loaded dermal substitute promotes diabetic chronic wound healing and angiogenesis in rat

The incidence of chronic diabetic wounds is increasing with the growing number of diabetic patients, and conventional wound dressings have proven to be ineffective in treating them. To address this challenge, researchers have developed artificial dermal substitutes using collagen and hyaluronic acid, which are crucial extracellular matrices. However, these subsitiues lack precision and targeted treatment. To overcome this limitation, a gene liposome nanocomplex-loaded dermal substitute (GDS) has been developed as a potential solution. This innovative biomaterial combines the benefits of liposome nanocomplexes with dermal substitutes to offer a more accurate and effective treatment option for chronic diabetic wounds. The GDS has the ability to deliver genes and therapeutic agents specifically to the wound site, promoting angiogenesis and accelerating the wound healing process. Overall, the GDS presents a promising new approach for the clinical treatment of chronic diabetic wounds, offering a targeted and effective solution for this growing problem.

Antibacterial, biocompatible, hemostatic, and tissue adhesive hydrogels based on fungal-derived carboxymethyl chitosan-reduced graphene oxide-polydopamine for wound healing applications

In this study, we developed biocompatible, fungus-derived carboxymethyl chitosan (FCMCS)-reduced graphene oxide (rGO)-polydopamine (PDA)-polyacrylamide (PAM) (FC-rGO-PDA) hydrogels with excellent antibacterial, hemostatic, and tissue adhesive properties for wound healing applications. FC-rGO-PDA hydrogels were prepared by the alkali-induced polymerization of DA followed by the incorporation of GO and its reduction during the polymerization AM to form a homogeneously dispersed PAM network structure in FCMCS solution. The formation of rGO was verified using UV-Vis spectra. The physicochemical properties of hydrogels were characterized by FTIR, and SEM, water contact angle measurements, and compressive studies. SEM and contact angle measurements showed that hydrogels were hydrophilic with interconnected pores and a fibrous topology. In addition, hydrogels adhered well to porcine skin with an adhesion strength of 32.6 ± 1.3 kPa, . The hydrogels exhibited viscoelastic, good compressive (77.5 kPa), swelling, and biodegradation properties. An in vitro study using skin fibroblasts and keratinocytes cells showed the hydrogel had good biocompatibility. Testing against two model bacteria, viz. Staphylococcus aureus and E. coli revealed that the FC-rGO-PDA hydrogel has antibacterial activity. Furthermore, the hydrogel exhibited hemostasis properties. Overall, the developed FC-rGO-PDA hydrogel has antibacterial and hemostasis properties, high water holding capacity, and excellent tissue adhesive properties, which make it a promising candidate for wound healing applications.

In situ forming ROS-scavenging hybrid hydrogel loaded with polydopamine-modified fullerene nanocomposites for promoting skin wound healing

BACKGROUND

Excessive oxidative stress at the wound sites always leads to a prolonged healing and even causes chronic inflammatory wounds. Therefore, antioxidative dressings with multiple features are desired to improve wound healing performance. Herein, we fabricated a ROS-scavenging hybrid hydrogel by incorporating mussel-inspired fullerene nanocomposites (C60@PDA) into gelatin methacryloyl (GelMA) hydrogel.

RESULTS

The developed C60@PDA/GelMA hydrogel showed a sustainable free radical scavenging ability, and eliminated ROS to protect cells against external oxidative stress damage. Besides, the hydrogel presented favorable cytocompatibility, hemocompatibility, and antibacterial ability in vitro. Furthermore, in a mouse full-thickness wound defect model, the in situ forming hybrid hydrogel accelerated wound closure by 38.5% and 42.9% on day 3 and day 7 over the control. Histological results demonstrated that hybrid hydrogels effectively enhanced wound healing on re-epithelialization, collagen deposition and angiogenesis.

CONCLUSION

Collectively, the C60@PDA/GelMA hydrogel could be a promising dressing for promoting cutaneous wound repair.

Biomedical applications of chitosan/silk fibroin composites: A review

Natural polymers have been used in the biomedical fields for decades, mainly derived from animals and plants with high similarities with biomacromolecules in the human body. As an alkaline polysaccharide, chitosan (CS) attracts much attention in tissue regeneration and drug delivery with favorable biocompatibility, biodegradation, and antibacterial activity. However, to overcome its mechanical properties and degradation behavior drawbacks, a robust fibrous protein-silk fibroin (SF) was introduced to prepare the CS/SF composites. Not only can CS be combined with SF via the amide and hydrogen bond formation, but also their functions are complementary and tunable with the blending ratio. To further improve the performances of CS/SF composites, natural (e.g., hyaluronic acid and collagen) and synthetic biopolymers (e.g., polyvinyl alcohol and hexanone) were incorporated. Also, the CS/SF composites acted as slow-release carriers for inorganic non-metals (e.g., hydroxyapatite and graphene) and metal particles (e.g., silver and magnesium), which could enhance cell functions, facilitate tissue healing, and inhibit bacterial growth. This review presents the state-of-the-art and future perspectives of different biomaterials combined with CS/SF composites as sponges, hydrogels, membranes, particles, and coatings. Emphasis is devoted to the biological potentialities of these hybrid systems, which look rather promising toward a multitude of applications.

Recent Applications of Melanin-like Nanoparticles as Antioxidant Agents

Nanosized antioxidants are highly advantageous in terms of versatility and pharmacokinetics, with respect to conventional molecular ones. Melanin-like materials, artificial species inspired by natural melanin, combine recognized antioxidant (AOX) activity with a unique versatility of preparation and modification. Due to this versatility and documented biocompatibility, artificial melanin has been incorporated into a variety of nanoparticles (NP) in order to give new platforms for nanomedicine with enhanced AOX activity. In this review article, we first discuss the chemical mechanisms behind the AOX activity of materials in the context of the inhibition of the radical chain reaction responsible for the peroxidation of biomolecules. We also focus briefly on the AOX properties of melanin-like NP, considering the effect of parameters such as size, preparation methods and surface functionalization on them. Then, we consider the most recent and relevant applications of AOX melanin-like NPs that are able to counteract ferroptosis and be involved in the treatment of important diseases that affect, e.g., the cardiovascular and nervous systems, as well as the kidneys, liver and articulations. A specific section will be dedicated to cancer treatment, since the role of melanin in this context is still very debated. Finally, we propose future strategies in AOX development for a better chemical understanding of melanin-like materials. In particular, the composition and structure of these materials are still debated, and they present a high level of variability. Thus, a better understanding of the mechanism behind the interaction of melanin-like nanostructures with different radicals and highly reactive species would be highly advantageous for the design of more effective and specific AOX nano-agents.