Immunoregulation in Diabetic Wound Repair with a Photoenhanced Glycyrrhizic Acid Hydrogel Scaffold

Sequential delivery of anti-inflammatory and anti-scar drugs by Rg3 liposome-embedded thiolated chitosan hydrogel eye drops for corneal alkali burn

Corneal injury is a major cause of inflammation, scarring, and even vision loss. The main treatment for corneal injury is local administration of eye drops. However, due to the limitation of the protective barrier of the eyes, conventional eye drops have the disadvantages of low bioavailability, high side effects, and limited efficacy. In this study, the anti-inflammatory agent dipotassium glycyrrhizate (DG) and the antifibrotic agent ginsenoside Rg3 were incorporated into a thermosensitive hydrogel in order to develop a multifunctional hybrid hydrogel eye drops (RDTG) for the synergistic treatment of corneal alkali burn. The hydrogel network was formed by thiolated chitosan and β-glycerophosphate through both physical and chemical crosslinking. DG was distributed in free state in the hydrogel, while Rg3 was incorporated into the hydrogel in the form of liposomes. Furthermore, RDTG showed the characteristic of sequential drug-release. In vivo studies using a mouse model of corneal alkali burn have confirmed that RDTG could effectively reduce inflammation, promote corneal wound healing, and inhibit corneal scar. Therefore, the efficient delivery of RDTG eye drops provided a promising approach for the treatment of corneal alkali burn.

Immuno-osteoinductive 3D printed hydrogel scaffolds with triple crosslinking and GA/EGCG release for bone healing

Bone defects, caused by trauma, osteomyelitis, or osteoporosis, represent a significant global health challenge in orthopedics. However, current bone repair strategies often neglect the critical role of the immune microenvironment, which can impede effective bone regeneration. To address this gap, we developed a 3D-printed triple crosslinked hydrogel scaffold incorporating slow-release glycopyrrolate (GA) and epigallocatechin gallate (EGCG), that it could promote bone regeneration by modulating the immune response. We evaluated their immunomodulatory and bone-regenerative effects through in vitro cellular experiments and rat cranial defect models. Results demonstrated that these scaffolds effectively modulated the immune microenvironment, reducing inflammation while promoting osteoblast differentiation and proliferation, thereby significantly enhancing new bone formation and density. In conclusion, our novel 3D-printed hydrogel scaffold offers a promising approach to bone defect repair through its unique combination of mechanical strength, immunomodulation, and osteogenesis. This study provides valuable insights into leveraging immunomodulatory agents for enhanced bone regeneration, highlighting potential clinical applications.

Antheraea pernyi silk nanofibrils with inherent RGD motifs accelerate diabetic wound healing: A novel drug-free strategy to promote hemostasis, regulate immunity and improve re-epithelization

The chronic inflammation and matrix metalloprotease (MMP)-induced tissue degradation significantly disrupt re-epithelization and delay the healing process of diabetic wounds. To address these issues, we produced nanofibrils from Antheraea pernyi (Ap) silk fibers via a facile and green treatment of swelling and shearing. The integrin receptors on the cytomembrane could specifically bind to the Ap nanofibrils (ApNFs) due to their inherent Arg-Gly-Asp (RGD) motifs, which activated platelets to accelerate coagulation and promoted fibroblast migration, adhesion and spreading. These degradable nanofibrils served as effective competitive substrates to reduce MMP-induced tissue degradation. ApNFs and their enzymatic hydrolysates could modulate macrophage polarization due to their RGD motifs. RNA sequencing further revealed that ApNFs treatment activated the JAK2-STAT5b and PI3K-Akt signaling pathways while suppressed the NF-κB, IL-17 and TNF signaling pathways in macrophages. The full-thickness skin wound experiments confirmed that ApNFs significantly accelerated wound healing in both diabetic and non-diabetic rats. Notably, in diabetic wound, ApNFs and their enzymatic hydrolysates polarized the accumulated M1-type macrophages into M2-type, which promoted the wound to get rid of the inflammatory stage and transition to the following proliferative stage, improving the wound healing percentage on day 14 from 74.9 % to 93.2 % by facilitating collagen deposition, angiogenesis and re-epithelization. These results demonstrate that ApNFs are promising drug-free diabetic wound dressings with favorable inherent immunoregulatory properties for biomedical translation.

Zn-DHM nanozymes regulate metabolic and immune homeostasis for early diabetic wound therapy

Diabetic wounds heal slowly or incompletely because of the microenvironment of hyperglycemia, high levels of reactive oxygen species (ROS), excessive inflammation, metabolic disorders and immune dysregulation, and the therapeutic effect is limited only by disruption of the reactive oxygen species (ROS)-inflammation cascade cycle. Here, a novel metal-polyphenolic nanozyme (Zn-DHM NPs) synthesized by the coordination of Zn2+ with dihydromyricetin (DHM) was designed, which not only has a superior ability to scavenge ROS and promote cell proliferation and migration but also functions in the regulation of metabolism and immune homeostasis. In vitro and in vivo experiments and RNA sequencing analyses revealed that Zn-DHM NPs could increase the levels of intracellular SOD and CAT enzymes to scavenge ROS and maintain the level of the mitochondrial membrane potential to reduce apoptosis. In terms of glucose metabolism, Zn-DHM NPs downregulated excessive levels of intracellular glucose and HK2, inhibited excessive glycolysis and downregulated the AGE-RAGE pathway to restore cellular function. In terms of immune regulation, Zn-DHM NPs not only downregulate M1/M2 levels to promote tissue repair but also maintain Th17/Treg homeostasis, downregulate the IL-17 signaling pathway to reduce inflammation, and upregulate FOXP3 to maintain immune homeostasis, thereby promoting early wound healing in diabetic mice. The development of Zn-DHM NPs provides a new therapeutic target to promote early healing of diabetic wounds.

Glucose-regulating hydrogel for immune modulation and angiogenesis through metabolic reprogramming and LARP7-SIRT1 pathway in infected diabetic wounds

In diabetic-infected wounds, the local hyperglycemic state leads to unique pathological characteristics of diabetic ulcers, such as secondary chronic infections, abnormal angiogenesis, oxidative stress, and diabetic peripheral neuropathy. Glucose oxidase (GOx) is an enzyme that catalyzes the breakdown of glucose into hydrogen peroxide and gluconic acid, making it a candidate enzyme for regulating the hyperglycemic microenvironment in diabetic wounds. However, multifunctional hydrogel therapeutic systems built around the glucose-lowering capability of GOx have rarely been reported. Here, we loaded stachydrine and Au-FePS3 nanosheets onto a quaternized chitosan (QC) - oxidized dextran (OD) hydrogel to construct a synergistic QC-OD@AF/S hydrogel therapeutic system. In vitro experiments showed that Au-FePS3 possesses GOx-POD cascade catalytic activity, capable of reducing glucose concentration and decomposing generated hydrogen peroxide into reactive oxygen species (ROS). Concurrently, Au-FePS3 exhibits excellent photothermal performance under 808 nm infrared light, synergistically exerting antibacterial capabilities with ROS and quaternary ammonium groups. Stachydrine has been demonstrated to mediate the metabolic reprogramming of macrophages and alleviate high-glucose-induced oxidative stress and impairment of angiogenesis in HUVECs through the LARP7-SIRT1 pathway. In summary, the QC-OD@AF/S hydrogel demonstrates superior capabilities in antibacterial activity, immune modulation, promotion of angiogenesis, and reduction of local glucose concentration, making it a potential clinical therapy.

Recent advances in smart hydrogels derived from polysaccharides and their applications for wound dressing and healing

Owing to their inherent biocompatibility and biodegradability, hydrogels derived from polysaccharides have emerged as promising candidates for wound management. However, the complex nature of wound healing often requires the development of smart hydrogels---intelligent materials capable of responding dynamically to specific physical or chemical stimuli. Over the past decade, an increasing number of stimuli-responsive polysaccharide-based hydrogels have been developed to treat various types of wounds. While a range of hydrogel types and their versatile functions for wound management have been discussed in the literature, there is still a need for a review of the crosslinking strategies used to create smart hydrogels from polysaccharides. This review provides a comprehensive overview of how stimuli-responsive hydrogels can be designed and made using five key polysaccharides: chitosan, hyaluronic acid, alginate, dextran, and cellulose. Various methods, such as chemical crosslinking, dynamic crosslinking, and physical crosslinking, which are used to form networks within these hydrogels, ultimately determine their ability to respond to stimuli, have been explored. This article further looks at different polysaccharide-based hydrogel wound dressings that can respond to factors such as reactive oxygen species, temperature, pH, glucose, light, and ultrasound in the wound environment and discusses how these responses can enhance wound healing. Finally, this review provides insights into how stimuli-responsive polysaccharide-based hydrogels can be developed further as advanced wound dressings in the future.

A glycopeptide-based pH-responsive hydrogel promotes diabetic wound healing via antimicrobial and remodeling microenvironment

Treating bacterium-infected diabetic wounds remains a major medical challenge. Antimicrobial activity, remodeling of oxidative stress-heavy and angiogenesis-impaired microenvironments are critical factors for effective wound healing. Hydrogels can function as drug delivery systems that encompass all these capabilities to enhance wound healing. In this study, we developed a glycopeptide-based hydrogel (DA/bF@OD-PL) composed of oxidized dextran (OD), polylysine (PL), dopamine (DA), and basic fibroblast growth factor (bF). This hydrogel exhibits excellent structural integrity, injectability, adhesion properties, swelling capacity, and degradability. Notably, the hydrogel is responsive to acidic conditions due to the presence of Schiff base bonds, enabling it to respond to the acidic environment characteristic of bacterium-infected wounds and release its encapsulated drugs accordingly. Among these components, PL has a strong antibacterial effect and can easily kill S. aureus and E. coli. DA effectively scavenges multiple reactive oxygen species (ROS) and induces macrophage polarization to M2 macrophages to alleviate oxidative stress. bF upregulates the expression of CD31 and vascular endothelial growth factor (VEGF) to promote angiogenesis. Finally, we validated the ability of this hydrogel to promote rapid wound healing in an S. aureus-infected diabetic mouse wound model.

A multifunctional metformin loaded carboxymethyl chitosan/tannic acid/manganese composite hydrogel with promising capabilities for age-related bone defect repair

As the global population ages, age-related bone defects have become a major public health challenge. The decline in bone tissue repair capacity among the elderly is primarily attributed to the senescence of bone marrow mesenchymal stem cells (BMSCs), which leads to reduced proliferation and differentiation capabilities, thereby impeding the bone healing process. Additionally, the deterioration of the bone microenvironment, characterized by chronic inflammation and oxidative stress, further complicates bone repair. To address these issues, a multifunctional hydrogel drug delivery system, the metformin-loaded carboxymethyl chitosan/tannic acid/manganese (MCTM) hydrogel was developed. This system integrates the synergistic effects of CMCS, TA, Mn2+, and metformin to effectively alleviate BMSCs senescence, optimize the local chronic inflammatory microenvironment, eliminate oxidative stress, and reduce post-implantation infection risks. Detailed material characterization revealed that the introduction of Mn2+ significantly enhances the mechanical properties and optimizes the degradation characteristics of the CMCS/TA hydrogel, ensuring continuous and stable drug release at tissue repair sites. In vitro and in vivo experiments demonstrated MCTM's excellent biocompatibility and its ability to combine stem cell senescence alleviation with bone repair microenvironment improvement, thereby effectively overcoming various adverse factors affecting bone defect repair in the elderly. This study presents a promising strategy for enhancing bone regeneration under senescent conditions.

Sinomenine-glycyrrhizic acid self-assembly enhanced the anti-inflammatory effect of sinomenine in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common chronic systemic autoimmune disease that causes cartilage and bone damage in multiple joints, ultimately leading to disability. There is an urgent need to develop multidimensional strategies to treat RA. Sinomenine (SIN) has the distinctive pharmacological activity in treating RA, but its broader clinical application is limited by its exceedingly short half-life and adverse digestive tract effects. To overcome this obstacle, a self-assembled nanohydrogel (S-G hydrogel) was designed and produced with sinomenine (SIN) and glycyrrhizic acid (GA) without carriers or catalysts through noncovalent bonding. The S-G hydrogel could promote the absorption of SIN probably by protecting SIN from releasing and degrading in the acid circumstances. Oral intake of the S-G hydrogel significantly suppressed the overactivation of neutrophil via the Nf-κb and Mapk pathways in mice with RA. Furthermore, the S-G hydrogel regulated neutrophil activity by reversing apoptosis delay and decreasing autophagy-dependent NET formation. In summary, this study presents a self-assembled hydrogel with promising potential for clinical application, and offers a novel strategy to develop new drugs from the existing patent medicine composed of compounds from traditional Chinese medicine, as well as a special insight to elucidate the herb-matching mechanism in decoction prescriptions.

Peptide loaded self-healing hydrogel promotes diabetic skin wound healing through macrophage orchestration and inflammation inhibition

Chronic wound is one of the complications of diabetes, and its difficult cure results in increased disability rate and mortality rate, which brings serious psychological and economic burden to patients. Excessive inflammation is one of the key reasons for poor tissue healing in chronic diabetic wounds. Herewith, the development of wound dressings with anti-inflammation and promoting tissue repair is of great significance for the treatment of chronic diabetic wounds. In this work, the Ac2-26 (Ac) peptide was loaded into the hyaluronic acid (HA) complex hydrogel for diabetic wound therapy. The hydrogel containing Ac had good mechanical properties, self-healing properties, and adhesion. It could down-regulate the M1/M2 phenotype of macrophages effectively, thereby promoting collagen type Ⅲ (COL-Ⅲ) secretion and migration of L929 and angiogenesis of HUVECs. Furthermore, the hydrogel containing Ac could restore the oxidative phosphorylation process and down-regulated toll-like receptor signaling pathway and inflammatory gene expression in the pathological environment of diabetes, showing a superior anti-inflammatory effect to ultimately promote the collagen deposition and angiogenesis in tissues for wounds repair. The HA complex hydrogel containing Ac demonstrated a good potential for clinical application in diabetic wound repair.

An NIR-responsive "4A hydrogel" encapsulating wormwood essential oil: through antibacterial, antioxidant, anti-inflammation, and angiogenic to promote diabetic wound healing

The incorporation of hydrogels with biocompatible functional components to develop wound dressings exhibiting potent antibacterial, antioxidant, anti-inflammatory, and angiogenic properties to promote diabetic wound healing is highly desirable yet continues to pose a significant challenge. In this study, wormwood essential oil (WEO) is successfully encapsulated within black phosphorus (BP) using a physical extrusion technique. Subsequently, this composite is encapsulated within biocompatible gelatin methacrylate (GelMA) and hyaluronic acid methacrylate (HAMA) hydrogels to create multifunctional hydrogel dressing (WEO@BP/GH). In comparison to traditional hydrogels, BP enhances the encapsulation stability of WEO and improves the microenvironmental regulation capabilities through NIR-triggered release of WEO. Systemic in vitro experiments demonstrate that synergistic interaction between the diverse bioactive components of WEO and photothermal effects of BP results in highly effective antibacterial activities against S. aureus and E. coli, antioxidant of scavenging ROS, anti-inflammation of downregulating M1/M2 macrophages ratio, and angiogenic properties. Moreover, the in vivo tests demonstrate that WEO@BP/GH hydrogel significantly enhances high-performance diabetic wound repair through the acceleration of hemostasis, promotion of collagen deposition, regulation of inflammatory responses, and facilitation of vascularization. The findings indicate that WEO@BP/GH hydrogel holds considerable promise as a candidate for microenvironment regulation and effective diabetic wound healing across various clinical applications.

Dynamic multistage nanozyme hydrogel reprograms diabetic wound microenvironment: synergistic oxidative stress alleviation and mitochondrial restoration

Chronic diabetic wounds remain a significant clinical challenge due to persistent bacterial infections, oxidative stress, impaired angiogenesis, and mitochondrial dysfunction. Traditional therapies often fail to address these interrelated pathological factors, highlighting the urgent need for innovative solutions. Here, we present a Mn-ZIF@GOx/BC (MZGB) hydrogel system, where Mn-ZIF@GOx (MZG) nanozymes are successfully integrated into a bacterial cellulose (BC) hydrogel via hydrogen bonding and electrostatic interactions. The MZGB hydrogel lowers wound pH by oxidizing excess glucose into gluconic acid. It exhibits strong ROS scavenging capabilities through its superoxide dismutase and catalase-like activities, while simultaneously providing oxygen. By restoring redox homeostasis, it protects mitochondrial function and enhances cellular energy metabolism. By reprogramming macrophages, MZGB creates a favorable immune microenvironment, significantly promoting angiogenesis through paracrine mechanisms. This facilitates cell-to-cell communication, forming a positive feedback loop. Moreover, MZGB demonstrates ROS-independent antibacterial properties. BC hydrogel ensures adhesion and moisture regulation, forming a protective barrier and maintaining an optimal wound environment. This multifunctional hydrogel represents a promising nanotherapeutic approach for efficiently treating diabetic wounds by precisely regulating the wound microenvironment.

Manipulating gelatinization, retrogradation, and hydrogel properties of potato starch through calcium chloride-controlled crosslinking and crystallization behavior

Due to the inherent susceptibility of single-polymer starch molecules to retrogradation, the practical application of green starch hydrogels is remarkably limited. Here, we propose a simple strategy to achieve the multifunctionality of starch hydrogels by employing polymer amorphization. Calcium chloride was used to promote the gelatinization of starch granules, disrupting their crystalline structure without the need for heating. Additionally, during the initial stage of hydrogel formation, the effects induced by calcium chloride effectively suppressed starch retrogradation. This suppression induced the formation of uniform aggregates of polymer chains, enabling tunable polymer amorphization and the coexistence of free hydroxyl and hydrogen-bonding hydroxyl groups. The multiscale microstructure yielded starch-based hydrogels with favorable water-retention capabilities, high transparency (86.39 %), improved self-adhesive and self-healing properties, excellent stretchability (146 %), tissue-like ultra-softness (Young's modulus <10 kPa), and anti-freezing properties (<-50 °C). Overall, this study systematically elucidates the underlying mechanisms of CaCl2 impacts on starch gelatinization, retrogradation, and hydrogel properties, paving the way for the on-demand functionality of starch hydrogels through regulated crystallization.

Membrane biomimetic nanoenzyme-incorporated hybrid glycyrrhizic acid hydrogel for precise mitochondrial ROS scavenging for osteoarthritis treatment

Osteoarthritis (OA) is a progressive degenerative disorder which severely threatens the quality of life of older individuals. OA progression is closely related to heightened levels of mitochondrial reactive oxygen species (mtROS). Although nanozymes have a good ROS-scavenging effect, they cannot precisely scavenge mtROS because of the immune rejection of cell membranes, lysosomal escape, and the inability of conventional nanozymes to directly target mitochondria. Dual-target nanozymes were engineered to precisely scavenge mtROS in chondrocytes. We used chondrocyte membrane-camouflaged TPP-modified hollow Prussian blue nanozymes and subsequently encapsulated these nanozymes in a hybrid glycyrrhizic acid hydrogel. The therapeutic efficacy and underlying mechanisms were assessed in vitro and in vivo. The novel nanozymes enhanced cell selectivity, immune evasion capabilities, and mitochondrial targeting. The dual-targeted nanozymes exerted a pronounced therapeutic impact on inflammatory chondrocytes, mitigated mtDNA leakage by precisely scavenging mtROS, dampened cGAS-STING-NF-κB signaling, and enhanced chondrocyte function. The hybrid hydrogels also exhibited improved therapeutic outcomes. We confirmed the beneficial effects of the nanozyme-hydrogel combination on OA progression in mice. The nanozyme-hydrogel combination can reduce precisely scavenge mtROS in chondrocytes, avoiding the leakage of mtDNA and suppressing the cGAS-STING-NF-κB signaling pathway, thereby decreasing inflammatory responses and alleviate OA progression.

Multifunctional natural starch-based hydrogels: Critical characteristics, formation mechanisms, various applications, future perspectives

With the growth of the global population and increasing concern for environmental issues, the development of sustainable and eco-friendly materials has become increasingly important. Starch, as a renewable resource, is one of the most abundant polysaccharides in nature, with the advantages of good biocompatibility, high biodegradability, and low cost. Starch-based hydrogels (SBHs) have attracted widespread attention due to their unique physical and chemical properties. This article provides a comprehensive review of the latest research progress in SBHs, discussing their main characteristics, formation mechanisms, diverse applications, and future development trends. First, it outlines the biocompatibility, degradability, water absorption and retention, environmental responsiveness, and mechanical strength of SBHs. Then, it elaborates in detail on the formation mechanisms of SBHs, including physical crosslinking (hydrogen bonding, electrostatic interactions, host-guest and coordination interactions), chemical crosslinking (such as initiators, heat, light, radiation, and click reactions), and synergistic effects. Subsequently, it analyzes the applications of SBHs in cutting-edge fields such as flexible sensors, medical dressings, drug delivery, tissue engineering, soil protection, wastewater treatment, and food packaging. Finally, it summarizes the challenges in current research and provides an outlook on future development trends, emphasizing the importance of further optimizing the performance of SBHs to meet broader industrial needs and environmental protection goals. This review not only provides a systematic theoretical framework for the study of SBHs but also charts a course for their innovative applications in the field of sustainable materials, playing a significant role in advancing the continuous development of this area.

Smart Silk-Based In Situ Sol-Gel Modulates Rectal Microenvironment for Effective Ulcerative Colitis Alleviation

Ulcerative colitis (UC) is a chronic inflammatory bowel disease, with untreated cases often progressing to colorectal cancer. Current treatments aim to induce inflammatory remission but often neglect the surrounding microenvironment, which significantly impairs mucosal healing and contributes to treatment failures. This study presents a novel silk fibroin-based fucoidan (SFU) in situ rectal gel, with sol-gel transition confirmed through rheological analysis under physiological pH and temperature conditions. The SFU gel exhibits strong antioxidant activity, achieving a DPPH radical scavenging rate of 73.3 ± 1.52%. The gel efficiently reduces reactive oxygen species (ROS) and nitric oxide (NO) production, demonstrating its reliable antioxidant effects. In a DSS-induced UC mouse model, SFU effectively alleviates colitis symptoms, including weight loss and disease activity index (DAI) reduction, with improved stool consistency and reduced rectal bleeding. Moreover, SFU therapy reprograms macrophages from proinflammatory M1 to anti-inflammatory M2 phenotypes, significantly lowering IL-6 and TNF-α levels, suggesting anti-inflammatory properties. Furthermore, SFU increased tight junction proteins Occludin-1 and ZO-1, indicating gut mucosal barrier integrity. SFU treatment restores goblet cells and mucin production while preventing fibrosis, demonstrating its potential as a natural therapy for UC treatment.

Gelatin-based adaptive injectable nanocomposite hydrogel for closure of irregular wounds and immunoregulation in diabetic wound healing

Chronic wounds are a major challenge in diabetic patients, exacerbated by disorders of blood perfusion and angiogenesis, bacterial infection, oxidative stress, and inflammation and immune imbalance. Bioactive hydrogels with multifunctional immunomodulatory properties offer promising solutions for diabetic wound management. However, many hydrogels lack adaptability and rely on costly cytokines, cell therapies, or drugs with side effects. This study introduces a novel gelatin-based injectable nanocomposite hydrogel (GelDE-OCS@MOF@Pl) for irregular wound closure and diabetic ulcer healing. This naturally derived macromolecular hydrogel exhibits exceptional biocompatibility and in situ molding capabilities, enabling effective closure and repair of irregular wounds. The GelDE-OCS@MOF@Pl hydrogel serves dual therapeutic functions by establishing a protective physical barrier while intelligently regulating polyphyllin (Pl) release in response to pH variations, thereby simultaneously eliminating bacterial pathogens, scavenging reactive oxygen species, and suppressing excessive inflammation for providing a suitable microenvironment for angiogenesis and epithelialization. This nanocomposite hydrogel effectively promotes diabetic wound healing through coordinated modulation of the wound immune microenvironment, demonstrating multifunctional therapeutic effects including antibacterial activity, oxidative stress alleviation, and anti-inflammatory action, thereby presenting a promising treatment strategy for chronic diabetic wounds.

Hydrogel-mediated delivery of baicalein for the effective therapy of MRSA-infected diabetic wounds by immune response and moderate photothermal effects

Persistent bacterial infections and the imbalance in immune regulation induced by oxidative stress present a significant challenge in diabetic wound healing. In this study, we developed a novel dual-network hydrogel system composed of chitosan/polyacrylic acid (PEC) and polyoxometalate PMo12 (PMo12-PEC) loaded with baicalein (BA), designated as PMo12-BA-PEC, for the treatment of methicillin-resistant Staphylococcus aureus (MRSA)-infected diabetic wounds. The hydrogel demonstrated enhanced mechanical strength and elasticity, facilitating effective wound adherence and accommodating tissue movement. Upon 808 nm near-infrared (NIR) light irradiation, the photothermal properties of PMo12 enabled controlled low-temperature hyperthermia and accelerated BA release. Remarkably, the hydrogel achieved an antibacterial efficacy of 99.45% ± 0.12% against MRSA following 5 minutes of NIR exposure while exhibiting potent antioxidant and anti-inflammatory capabilities to scavenge reactive oxygen species and mitigate inflammatory responses. Comprehensive evaluation revealed that the PMo12-BA-PEC hydrogel significantly promoted angiogenesis, enhanced collagen deposition, inhibited bacterial growth, and modulated immune regulation, thereby accelerating the wound healing process in diabetic rat models. These findings suggest that the PMo12-BA-PEC hydrogel represents a promising biomaterial platform for clinical management of diabetic wounds and potential treatment of oxidative stress-related disorders.

Micromotion-Driven "Mechanical-Electrical-Pharmaceutical Coupling" Bone-Guiding Membrane Modulates Stress-Concentrating Inflammation Under Diabetic Fractures

The use of piezoelectric materials to convert micromechanical energy at the fracture site into electrical signals, thereby modulating stress-concentrated inflammation, has emerged as a promising treatment strategy for diabetic fractures. However, traditional bone-guiding membranes often face challenges in diabetic fracture repair due to their passive and imprecise drug release profiles. Herein, a piezoelectric polyvinylidene fluoride (PVDF) fibrous membrane is fabricated through electrospinning and oxidative polymerization to load metformin (Met) into a polypyrrole (PPy) coating (Met-PF@PPy), creating a "mechanical-electrical-pharmaceutical coupling" system. In a micromotion mechanical environment, Met-PF@PPy converts mechanical energy into electrical signals, activating the electrochemical reduction of PPy and triggering stress-responsive Met release. The generated electrical signals suppress inflammation through M1-to-M2 macrophage polarization and simultaneously enhance osteogenesis. Simultaneously, Met inhibits the NF-κB pathway to reduce pro-inflammatory cytokines while activating the AMPK pathway to promote osteogenesis and angiogenesis. In a diabetic mouse femoral fracture model, Met-PF@PPy significantly reduces inflammatory markers, enhances vascularization, and increases bone mineral density and bone volume fraction by over 30%. This "force-electric-drug coupling" strategy provides an innovative approach for active regulation in diabetic fracture repair and offers a versatile platform for advancing piezoelectric materials in regenerative medicine.

High-affinity, broad-spectrum, "centipede-like" multi-branched drug conjugates, anchored to the S protein, for blocking coronavirus infection

Over the past two decades, various coronaviruses have posed a severe threat to human life and health, with the spike protein (S protein) being a critical protein for infecting host cells. Glycyrrhizic acid (GA), as a natural drug, can inhibit the infection of coronaviruses by binding to the receptor-binding domain (RBD) of the S protein. However, issues like poor water solubility and weak binding affinity with the S protein have hindered its further application. Therefore, drawing inspiration from the biological structure of centipedes, a ROS-responsive multi-branched drug conjugate (ODPAG) was constructed through a "polymer-drug linkage" strategy using dextran as the backbone and GA as the active "claw". ODPAG exhibited drug loading of 22.0 ± 0.2% (OD40kPAG) and 19.7 ± 0.1% (OD450kPAG), showing ROS responsiveness with a half-life 6.4 times that of GA (OD40kPAG) and 5.4 times longer (OD450kPAG). In in vitro antiviral experiments, ODPAG exhibited an enhanced binding affinity to the S protein, with IC50 values of 1.33 μM (OD40kPAG) and 0.89 μM (OD450kPAG) against SARS-CoV-2 pseudovirus, demonstrating exceptional antiviral efficacy. These results collectively indicate that ODPAG can block coronavirus infection by binding to the S protein, exhibiting significant potential in addressing the current challenges posed by the novel coronavirus. Additionally, the "polymer-drug conjugate" strategy employed in this process is efficient, cost-effective, and offers new insights for combating future emergent coronaviruses.

Dual functional photocatalytic hydrogel coupled with hydrogen evolution and glucose depletion for diabetic wound therapy

Diabetic foot ulcers (DFUs), a common and serious complication of diabetes mellitus, are exacerbated by hyperglycemia-induced chronic inflammation and oxidative stress, which collectively impede the wound-healing process. Effective management requires coordinated regulation of the pathological microenvironment through localized glucose reduction, anti-inflammatory modulation, and reactive oxygen species (ROS) scavenging. This study developed an injectable functionalized hydrogel incorporating a Bi nanocrystal-decorated bismuth tungstate/hydrogen-doped titanium dioxide (Bi2WO6/H-TiO2) heterojunction with dual photocatalytic properties: glucose degradation and hydrogen evolution. Upon exposure to light, the hydrogel exploits glucose in the wound as the sacrificial substrate to simultaneously decrease local glucose concentrations and facilitate in situ hydrogen production. The released hydrogen exhibits potent antioxidant and anti-inflammatory activities, synergizing with glucose consumption to inhibit cellular apoptosis and accelerate tissue repair. A systematic evaluation revealed enhanced cell proliferation and migration in hyperglycemic in vitro models. In vivo experiments using a diabetic murine model demonstrated 50 % wound closure within 3 days, accompanied by improved angiogenesis and collagen remodeling. This photocatalytic synergistic strategy represents a clinically promising modality for diabetic wound treatment by regulating the microenvironment and restoring redox homeostasis.

Fabrication of Janus-adhesion Multifunctional Hydrogel Based on β-cyclodextrin for Wound Dressing

Conventional wound dressings frequently face challenges of insufficient mechanical strength, inadequate adhesion, irregular drug release, and contamination from adherence to extraneous surfaces. These issues can lead to wound contamination and the risk of secondary injuries. In this work, a robust, thermoresponsive wound dressing is developed based on pH/thermal-responsive supramolecular hydrogels, synthesized by integrating N-isopropyl acrylamide, carboxymethyl cellulose, and β-cyclodextrin-grafted poly(acrylic acid). The novel finding is that the hydrogel exhibits a Janus-like adhesion, wherein it adheres stably to the wound while losing adhesion to external environments resulting in reduced accumulation of impurities. The prepared hydrogels can self-heal at low temperatures. It has antioxidant properties and excellent biocompatibility that can continuously and stably release active medicines. In vivo experiments in a rat model of full-thickness skin wounds show that the hydrogels positively accelerate wound healing. The unique physicochemical properties and biological interactions of this multifunctional supramolecular hydrogel provide a promise for advancing wound management by modulating tissue adhesion.

Supermolecular poly-N-acryloyl glycinamide/polyglutamic acid/Fe3+ hydrogel incorporated with bioactive small extracellular vesicles promote diabetic wound healing by suppressing ferroptosis

Poorly-controlled blood glucose frequently develop in diabetic wounds and hydrogel has been reported of great performance for diabetic wound healing. Consequently, we prepared poly-N-acryloyl glycinamide (PNAGA) and introduced polyglutamic acid (γ-PGA), Fe3+, small extracellular vesicles (sEVs) into PNAGA to form a dual physical cross-linking supramolecular hydrogel system (PFF) for diabetic wound healing. In this study, we successfully synthesized the PFF hydrogel and extracted the sEVs that were incorporated into PPF as PPF/sEVs. In our research, we find that PFF hydrogel possessed continuous porous structure and, exceptional resilience, excellent extensibility and flexibility, closely mimicking the mechanical performance of human skin. Moreover, the PFF/sEVs hydrogel could release sEVs, playing a critical role in wound healing. Our results showed PFF/sEVs hydrogel improved the wound healing characterized by shorter wound closure time and enhanced blood vessel density in vivo. Also, sEVs counteracted the inhibitory effects of high glucose on proliferation, migration, tube differentiation, malondialdehyde (MDA) and glutathione (GSH) levels, which may attribute to the inhibition of ferroptosis by influencing free fatty acids (FFA) metabolism in vitro. Our findings indicated that the low-cost, biocompatible, and multifunctional bioactive PFF supramolecular hydrogel loaded with sEVs hold tremendous application potential as a clinical platform for diabetic wound healing.

Flexible and low-temperature-resistant double-network hydrogel with a bionic octopus-tentacle-like structure for integrated supercapacitor and nanogenerator sensor fabrication

Flexible and stretchable hydrogels are important components of flexible electronics; however, they are typically easily detached upon repeated high-strain stretching because of their smooth surfaces and cannot be used at subfreezing temperatures because of ice formation. To address these shortcomings, we prepared a low-temperature-resistant and flexible double-network hydrogel with a bionic octopus-tentacle-like structure composed of polyvinyl alcohol and sodium alginate. We also verified its suitability for developing high-performance, flexible, stretchable, and environmentally durable supercapacitors and nanogenerator sensors. The influence of melting temperature on the hydrogel's surface morphology decreased the interfacial resistance. The fabricated supercapacitor demonstrated exceptional performance, with 1326.5 mF cm-2 (areal capacitance) at 1 mA cm-2, a maximum energy and power densities of 172.3 μWh cm-2, and 708.6 mW cm-2, respectively, outperforming most integrated supercapacitors previously reported. The corresponding nanogenerator sensor demonstrated outstanding suitability for energy harvesting and low-temperature sensing, with potential applications in underwater information transmission using international Morse code. The results of this study paves the way for the fabrication of intelligent wearable electronics and solves the problems associated with the fabrication of flexible and low-temperature-resistant hydrogels.

An antioxidant, antibacterial, and immunoregulatory konjac glucomannan-based nanocomposite hydrogel for promoting skin wound healing

Managing open skin wounds remains a notable challenge in clinical practice, with wound dressings gradually becoming an essential strategy for such treatment. To effectively regulate the wound healing microenvironment, we developed an antibiotic-free nanocomposite hydrogel by combining guanosine-based supramolecular G-quadruplexes (G4), angiogenic deferoxamine (DFO), konjac glucomannan (KGM), and zinc ions through a one-pot mixing strategy. The borate esters in G4 endow the hydrogel with a strong radical-scavenging ability. As a mannose-containing polysaccharide, KGM does not affect the self-assembly of G-quartets and also induces macrophage polarization toward the anti-inflammatory M2 phenotype without requiring expensive exogenous cytokines. Zinc ions were introduced to enhance the hydrogel's mechanical properties by forming coordination interactions with DFO and endowing the hydrogel with excellent antibacterial properties. Collectively, this biocompatible hydrogel accelerates skin wound closure and promotes mature tissue regeneration by stimulating macrophage polarization toward the M2 phenotype, expediting collagen deposition, alleviating inflammation, and enhancing angiogenesis. Overall, this multifunctional hydrogel can serve as a versatile wound dressing material in regenerative medicine.

Endogenous electric field-driven neuro-immuno-regulatory scaffold for effective diabetic wound healing

The pathological microenvironment in diabetic wounds is delineated by heightened inflammatory responses and persistent proinflammatory macrophage activity, which significantly hinders the wound healing process. Exogenous electrical stimulation (ES), by modulating the electric field distribution in wounds, has shown significant potential in treating inflammatory wounds. However, this approach relies on additional power sources and complex circuit designs. Here, a bionic neuro-immuno-regulatory (BNIR) system was proposed for reshaping the endogenous electric fields (EFs) through collecting ion flow. The BNIR system comprises microporous structure scaffolds and nanosheets, enabling swift biofluid collection and electrical signal transmission, with the ability to promote cell proliferation and migration and exhibit antioxidant properties. More importantly, the BNIR system induced the transition of M1 macrophages to M2 macrophages through neuro-immuno-regulatory. In diabetic rat skin wounds, the BNIR system significantly enhanced healing by simultaneously neuro-immuno-regulatory, promoting angiogenesis, scavenging ROS, and facilitating tissue remodeling. This work aims to advance the development of a bionic system for electrosensitive tissue repair.

A dual-network hydrogel patch fabricated by alginate/sulfobetaine methacrylate enriched with Dictyophora indusiata β-glucans promotes diabetic wound repair

This study developed a dual-network hydrogel patch loaded with Dictyophora indusiata β-glucans to enhance diabetic wound healing. The hydrogel combines a flexible primary network formed by polymerized sulfobetaine methacrylate with a rigid secondary alginate network crosslinked via metal ions. The resulting material demonstrates favorable mechanical properties for wound care, achieving 600 % elongation at break, 3.12 MPa compressive strength, and 1.5 kPa tissue adhesion strength. These characteristics meet with the physical requirements necessary for effective diabetic wound management. Furthermore, the β-glucans derived from Dictyophora indusiata, which serve as the main bioactive component, endowed the hydrogel patch with significant antioxidant and anti-inflammatory properties. Cellular experiments have demonstrated that the hydrogel patch significantly reduces reactive oxygen species levels in cells and inhibits inflammatory responses. In animal wound model, diabetic wound treated with a hydrogel patch achieved a closure rate of 98.26 % by the second week. Additionally, histological analyses revealed that the hydrogel patch significantly facilitates angiogenesis, collagen deposition, and re-epithelialization in diabetic wound. Consequently, the hydrogel patch based on β-glucans from Dictyophora indusiata appears to be an effective agent for promoting wound healing, thereby offering a novel therapeutic strategy for the repair of diabetic wound.

Development of hyaluronic acid-based hydrogels for chronic diabetic wound healing: A review

This research delves into the advancements in chronic skin wound treatment, with a particular focus on diabetic foot ulcers, utilizing hyaluronic acid (HA)-based hydrogels. Hyaluronic acid, an integral component of the skin's extracellular matrix, plays a crucial role in process such as inflammation, angiogenesis, and tissue regeneration. Due to their three-dimensional network structure, biocompatibility, hydrophilicity, and gas exchange capabilities, HA-based hydrogels are considered highly suitable for promoting wound healing. Nonetheless, pure HA hydrogels exhibit limitations including insufficient mechanical strength and rapid release of encapsulated substances. To address these limitations, the incorporation of bioactive materials such as chitosan and collagen was investigated. This combination not only optimized mechanical strength and degradation rates but also enhanced antibacterial and anti-inflammatory properties. Furthermore, responsive hydrogel dressings were developed to adapt to the specific characteristics of the diabetic wound microenvironment, enabling on-demand drug release. These advancements present new perspectives for the treatment of diabetic foot ulcers.

Trifunctional Sialylation-Based SF-ZIF@NA Hydrogel for Selective Osteoclast Inhibition and Enhanced Bone-Vessel Regeneration in Osteoporotic Bone Defects

Osteoporotic bone defects are challenging to repair due to imbalances in bone resorption and formation, coupled with insufficient vascularization. To address these issues, it develops a trifunctional hydrogel (SF-ZIF@NA) designed to selectively inhibit osteoclast activity and enhance vascularized bone regeneration. By enzymatically removing sialic acid, SF-ZIF@NA prevents precursor osteoclasts (pOCs) from fusing into bone-resorbing mature osteoclasts (mOCs), thereby preserving pOCs and their anabolic functions. Additionally, the hydrogel releases Zinc ion (Zn2⁺) in response to acidic conditions, promoting osteogenesis and angiogenesis. In vitro results confirmed that SF-ZIF@NA impedes osteoclast fusion, enhances platelet-derived growth factor-BB (PDGF-BB secretion from pOCs, and activates the FAK (focal adhesion kinase) signaling pathway to stimulate vascularized bone formation. In osteoporotic bone defect models, SF-ZIF@NA accelerated bone repair with increased bone density and vascularization. These findings demonstrate that SF-ZIF@NA offers a targeted and multifunctional strategy for osteoporotic bone regeneration by concurrently modulating osteoclast activity and promoting angiogenesis.

Selenium-Albumin Nanoaccelerator Hydrogel Promotes Wound Healing by Antibacterial, Anti-Inflammatory and Antioxidant along with Inhibits Scar Formation via Downregulating CD36

Wounds repairing after skin damage or diabetes remain a vast medical challenge, which often faces infection, inflammation, oxidative stress, and skin scarring. Herein, a multifunctional selenium-albumin nanoaccelerator hydrogel (H-Se NPs-Gel) is constructed based on the self-assembly of human serum albumin (HSA) with selenium nanoparticles (Se NPs) using carbomer as the carrier, it has remarkable antibacterial, anti-inflammatory, antioxidant and inhibits scarring properties than Se NPs for wound healing. Compared with Se NPs, H-Se NPs exhibit smaller particle sizes, exceptional stability, better antibacterial activity against common bacteria and MRSA, and superior antioxidant and anti-inflammatory capabilities in vitro without remarkable toxicity on skin cells. Importantly, it exhibits superior efficacy to Se NPs-Gel in accelerating the healing of full-thickness skin defects and diabetic wounds in mice. Interestingly, in a hypertrophic scar (HTS) model, H-Se NPs-Gel is more effective than Se NPs-Gel in inhibiting collagen formation to suppress scarring, which is mediated by the inhibition of CD36. The antagonistic effect of H-Se NPs on CD36 is also proved with the CD36 overexpression model. Furthermore, H-Se NPs-Gel demonstrates excellent safety in mice without systemic toxicity. H-Se NPs-Gel is an effective and safe therapy strategy for promoting wound healing and reducing scar formation in clinic.

A self-assembly enzyme-like hydrogel with ROS scavenging and immunomodulatory capability for microenvironment-responsive wound healing acceleration

On-demand responsive hydrogels are a promising solution for effective wound management as they can adjust their properties in response to changes in the wound environment, allowing them to provide tailored support for the healing process. However, the conventional hydrogels may not fully meet the diverse demands of the intricate healing process. Herein, a novel glycyrrhizic acid (GA) based self-assembly hydrogel coordinated with copper and polyphenol (GCP hydrogel) was developed to exhibit triggered release behavior in response to the microenvironment. The GCP hydrogel coordinated with copper and protocatechuic acid (PA) and self-assembled with GA, also exhibits enzyme-like properties by mimicking the cascade process of superoxide dismutase (SOD) and catalase (CAT), effectively scavenging reactive oxygen species (ROS). Furthermore, the on-demand release of Cu2+ at different stages of the wound healing process can not only enhance the antibacterial ability of methicillin-resistant Staphylococcus aureus (MRSA) but also intelligently promote angiogenesis with outstanding biocompatibility. In addition, the GCP hydrogel effectively modulated the activity of macrophages in response to inflammatory stimuli, exhibiting remarkable anti-inflammatory abilities and promoting tissue regeneration. The multifunctional GCP hydrogel platform has the potential to create a dynamic microenvironment that is conducive to tissue regeneration, making it an ideal candidate for smart wound management.

Three-Dimensional Bioprinting of Growth Differentiation Factor 5-Preconditioned Mesenchymal Stem Cell-Derived Exosomes Facilitates Articular Cartilage Endogenous Regeneration

The repair of articular cartilage defects remains a major regenerative and clinical challenge. Exosomes (Exos) derived from mesenchymal stem cells (MSCs) have good application potential in cartilage tissue engineering. Numerous studies have indicated that appropriate preconditioning methods can promote the therapeutic effect of Exos. Growth differentiation factor 5 (GDF-5) plays a critical role in chondrogenesis and regeneration. In this study, GDF-5 was used to precondition synovial mesenchymal stem cells (SMSCs) to increase the chondrogenic-promoting effect of Exos (G-Exos). In addition, we demonstrated that G-Exos rich in miR-383-3p increased the chondrogenic potential of SMSCs by activating the Kdm2a/SOX2 signaling pathway. On this basis, G-Exos were loaded into a glycyrrhizic acid/methacrylate-acylated hyaluronic acid (GA/HA/G-Exos) scaffold via digital light processing (DLP) bioprinting to maintain bioactivity and sustained release. The GA/HA/G-Exos scaffolds not only presented significant biological properties in vitro but also significantly promoted the remodeling of the joint cavity regenerative microenvironment and the regeneration of articular cartilage in Sprague-Dawley rats. This study provides a promising cell-free regenerative strategy for cartilage defect repair via the use of engineered exofunctionalized biological scaffolds.

Enhanced immunoregulation in traumatic urethral stricture repair utilizing a glycyrrhizic acid-infused antiswelling biogel scaffold

As a prevalent complication following urinary system trauma, urethral stricture is characterized by progressive fibrosis and luminal narrowing often leading to recurrent dysuria and impaired renal function. Current treatments including surgical interventions face challenges such as high recurrence rates and secondary stenosis. Hydrogel-based drug delivery systems offer therapeutic potential but are limited by material swelling under urinary flow and insufficient modulation of inflammatory microenvironments. This study introduces an innovative anti-swelling carrageenan biogel scaffold (Car/Ga) functionalized with glycyrrhizic acid (Ga), a dual anti-inflammatory and immunoregulatory phytochemical. The Car matrix ensures structural stability in biological fluids by resisting swelling-induced obstruction while Ga targets trauma-induced inflammatory cascades through M1 macrophage polarization mitigation to reduce fibrotic progression. In vitro and in vivo evaluations demonstrate that the Car/Ga system synergistically combines urine stability with immunomodulatory bioactivity, significantly reducing pro-inflammatory cytokine levels (iNOS) and promoting M2 macrophage polarization (Arg1). Histological analyses reveal attenuated collagen deposition and enhanced epithelial regeneration in urethral stricture models, highlighting its capacity to disrupt the inflammation-fibrosis cycle. By addressing both urine stability and immunological dysregulation, this dual-functional biogel represents a transformative strategy for precise urethral repair, demonstrating potential for clinical translation in urethral repair applications.

Application of sodium alginate and polyethylene glycol bilayer multifunctional hydrogel microneedles in infectious and diabetic wounds

Chronic wounds are challenging to heal due to persistent infection, prolonged inflammation, and impaired angiogenesis, which can ultimately lead to severe disabilities. Current treatment strategies are unable to provide the comprehensive conditions needed for effective chronic wound healing. Herein, we proposed a multifunctional microneedle patch for chronic wound healing, consisting of a needle-like drug-loading gel (DG) constructed with polyethylene glycol (PEG) and a backing hydrogel (BHG) layer constructed with sodium alginate. This design combines the therapeutic effects of drug delivery with the protective benefits of a hydrogel. The needle-like DG layer effectively penetrates the bacterial biofilm, releasing Erythromycin, Vaccarin, Demethylsuberosin, and Cyanidin, agents with synergistic antibacterial, anti-inflammatory, pro-angiogenic, and antioxidant effects in a temperature response-dependent manner. Together, these components address multiple barriers to chronic wound healing. The DG layer also maintains a moist wound environment for the wound. The pH-responsive properties of Cyanidin visually indicate the wound healing status. The multifunctional microneedle patch (DG@BHG) significant enhances healing in both infected and diabetic wounds, leveraging the combined effects of drug action and hydrogel support. This approach presents a novel therapeutic strategy for chronic wound healing by addressing infection, inflammation, and angiogenesis simultaneously.

Phycocyanin-based multifunctional hydrogel with self-healing, hemostatic, antioxidative, and antibacterial activity for wound healing

Hydrogels have gained significant attentions in the field of wound dressing since their resemblance to the extracellular matrix and excellent biocompatibility. Oxidative damage and bacterial infections resulting from an accumulation of reactive oxygen species (ROS) present significant challenges for chronic non-healing wounds. To address the issues of excessive ROS and bacterial infections during the wound healing process, we utilized C-phycocyanin, gelatin and silk fibroin as matrices to fabricate multifunctional hydrogels (PRG hydrogel), with rhein introduced as an antibacterial agent and tetracaine for pain relief. The hydrogel exhibited good stretchability, compressibility, and adhesion properties. Besides, the incorporation of dynamic covalent bonding endowed the hydrogels with good self-healing capabilities. The hydrogel exhibited good pro-coagulant hemostatic effects and favorable blood compatibility. Furthermore, the hydrogel possessed good antioxidant ability and can suppress S. aureus and P. aeruginosa. Additionally, the hydrogels showed high cytocompatibility and the rat trauma model further demonstrated that PRG-3 hydrogel could promote wound healing by reducing inflammation (TNF-α and IL-6) and accelerating collagen deposition and angiogenesis (CD31), which indicated that the hydrogel may as promise candidate for wound healing.

Functional Wound Dressing Based on Natural Compounds from Traditional Chinese Medicines─Magnolol for Accelerating Wound Healing

Traditional petroleum-based foam dressings offer limitations due to poor biocompatibility, long preparation cycle, and serious environmental pollution. In addition, free small molecules of incomplete polymers and residual toxic cross-linkers pose a threat to the health of patients and hinder the rapid repair of wounds. Recently, natural compounds extracted from plants have gained a lot of interest in the field of wound repair due to their good biocompatibility, biodegradability, and therapeutic effects. In this study, we successfully prepared magnolol-based porous foams by a simple one-pot method using magnolol herbal exhibiting good mechanical properties, hydrophobicity, and biocompatibility, and meets the requirements of wound dressings. The Janus composite dressing was prepared using a magnolol-based porous foam as the inner layer, PVA nonwoven fabric as the middle layer, and polyacrylate as the outer layer. The three-layer structure of magnolol-based porous foam/PVA nonwoven fabric/polyacrylate (MPF/PVA/PAAS) has the capacity to realize unidirectional diversion and rapid water locking of liquid. In vivo experimental data showed that MPF/PVA/PAAS dressing significantly promoted collagen deposition and angiogenesis, and could shorten the wound healing cycle from 14 days to 10 days, significantly accelerating the wound healing process compared to traditional wound dressings. Hence, magnolol-based foam dressings show great application potential in the field of wound treatment.

Engineered Exosomes Loaded in Intrinsic Immunomodulatory Hydrogels with Promoting Angiogenesis for Programmed Therapy of Diabetic Wounds

Inducing rapid angiogenesis by delivering specific biological cues is critical for diabetic wound healing. Nevertheless, the angiogenesis is hindered by the inflammatory microenvironment, and the immune cells fail to orchestrate immune responses to wound healing. Herein, vascular endothelial growth factor (VEGF) plasmids-loaded macrophage exosomes (Exos) were fabricated and enfolded in injectable self-healing hydrogels for programmed therapy of diabetic wounds through sequentially intrinsically modulating the inflammatory microenvironment and promoting angiogenesis. The hydrogels, formed via dynamical Schiff base reactions using modified polysaccharides, intrinsically regulate the inflammatory microenvironment via broad-spectrum antioxidant activity and macrophage phenotype regulation, restoring tissue redox and immune homeostasis. Furthermore, the hydrogels can stabilize and release the engineered exosomes. By integration of generation and release of VEGF by plasmids-loaded macrophage Exos, VEGF secretion by M2 macrophages, and enhanced binding of VEGF to VEGF receptor 2 by high affinity of sulfated chitosan, the intrinsic immunomodulatory hydrogels effectively promote the angiogenesis and accelerate the diabetic wound healing process.

Biobased Physicochemical Reversible Dual-Cross-Linked Hydrogel: Self-Healing, Antibacterial, Antioxidant, and Hemostatic Properties for Diabetic Wound Healing

Skin wound healing remains challenging due to a lack of ideal wound dressings suitable for acute and chronic wounds. This study introduced a biocompatible hydrogel wound dressing, synthesized through a green chemistry approach, specifically designed to meet the dual needs of acute and chronic wound care. The innovative strategy utilized sustainable biomaterials, soy protein, and vanillin, to construct a physical-reversible chemical dual-cross-linked hydrogel exhibiting high mechanical strength, excellent adhesion, and toughness. Schiff base reversible covalent bonds enabled rapid self-healing within 10 s, significantly improving durability. In a rat liver hemorrhage model, the hydrogel rapidly sealed wounds, achieving effective hemostasis, indicating great potential for acute wound care. Furthermore, vanillin imparted the hydrogel with antimicrobial and antioxidant properties, effectively accelerating diabetic chronic wound healing. This safe and efficient advanced biobased hydrogel offers a novel perspective for wound treatment and holds significant promise for clinical applications.

Immunomodulatory All-Natural Kelp Decellularized Scaffold Prepared Using Deep Eutectic Solvent with Angiogenic Properties for Accelerating Diabetic Wound Healing

Excessive oxidative stress, chronic inflammation, and impaired vascularization are the main barriers to diabetic wound repair. A decellularized extracellular matrix (dECM) with a native ECM structure is a promising biomaterial candidate for diabetic wound healing. However, the traditional decellularization process (reagents) can diminish the structural stability, mechanical properties, and bioactive components of dECM. To address these issues, we developed an intrinsically bioactive kelp decellularized scaffold (Im-Gly2) using natural and gentle deep eutectic solvents (DES) for accelerating diabetic wound healing. Im-Gly2 had a stable porous 3D structure (80.7 μm) and suitable mechanical properties, which could support cell growth, proliferation, and migration. Due to the retention of fucoidan, polyphenols (735.3 μg/g), and flavonoids, Im-Gly2 demonstrated intrinsic antioxidant and immunomodulatory effects. It effectively reduced reactive oxygen species (ROS) production in RAW264.7 macrophages and promoted their differentiation into the M2 phenotype. Notably, Im-Gly2 promoted tube formation through paracrine mechanisms by inducing the expression of transforming and proliferative cytokines from the RAW264.7 macrophage. In vivo, Im-Gly2 accelerated the healing of diabetic wounds by alleviating inflammation, angiogenesis, granulation tissue formation, collagen deposition, and re-epithelialization. Taken together, our study provides a novel strategy for fabricating a bioactive kelp dECM without cross-linking with exogenous substances for accelerating chronic diabetic wound healing.

Photoresponsive Blood-Derived Protein Hydrogels Packed with Bioactive Carbon Dots Modulate Mitochondrial Homeostasis and Reprogram Metabolism for Chronic Wound Healing in Diabetes

Autologous platelet concentrates (APC) represent a class of personalized regenerative materials for vascularized tissue regeneration. However, shortcomings including poor controllability of gel formation, lack of reactive oxygen species (ROS) scavenging ability, and deficient anti-inflammatory capacity restrict the tissue healing outcomes of APC. This study proposes an APC-based synergistic platform (CurCDs@iPRF-MA) for the treatment of chronic wounds in diabetes. Such a platform is composed of injectable platelet-rich fibrin (iPRF), gelatin methacryloyl (GelMA), and a carbogenic nanodrug from curcumin (CurCDs) that is injectable before the light-induced gel formation process, greatly facilitating the clinical applications of APC. Significantly, CurCDs@iPRF-MA can modulate the mitochondrial homeostasis under inflammatory conditions, activate the oxidative phosphorylation (OXPHOS) program, and regulate the diabetic microenvironment through metabolic reprogramming to achieve macrophage phenotype regulation and ROS elimination, as well as promote vascularization by releasing autologous growth factors, dramatically improving the healing efficacy of the chronic wounds in diabetes. This study offers a practical and effective approach to developing spatiotemporally controllable and multifunctional APC-based hydrogels for highly effective tissue regeneration.

Customized Hydrogel System for the Spatiotemporal Sequential Treatment of Periodontitis Propelled by ZEB1

Advanced periodontitis initiates with Porphyromonas gingivalis (P. gingivalis) infection, which subsequently triggers chronic inflammation, immune imbalance, and ultimately causes alveolar bone resorption. Traditional periodontal treatment focuses on the elimination of triggering factors, but tend to ignore the improvement of the inflammatory microenvironment and the remodeling of the osteogenic mineralization space. Herein, zinc-aluminum layered double hydroxide nanosheets (LDHs) loaded with icariin (ICA) are encapsulated into a gallic acid (GA)-modified hydroxybutyl chitosan hydrogel (GA-HBC), giving rise to a customized hydrogel system named GA-HBC-LIC, which can sequentially actualize antibacterial, anti-inflammatory, and remineralization functions. A neutral chemical-humoral space is created for osteogenesis via means of sequential regulation by the smart hydrogel. Concomitantly, appropriate mechanical properties and degradation performance of the hydrogel provide a desirable physical space for remineralization. In the spatiotemporal modulation of the hydrogel, zinc finger E-box-binding homeobox 1 (ZEB1) target of released zinc ions (Zn2+) action promotes macrophage polarization from M1 to M2 phenotype, thereby remodeling the immune microenvironment and releasing cytokines conducive to tissue regeneration. In sum, this study highlights the critical role of sequential inflammation regulation and the maintenance of osteogenic space in the regeneration of periodontal tissues, offering new insights for the clinical management of periodontitis.

Molecular-Cellular Two-Pronged Reprogramming of Inflammatory Soft-Tissue Interface with an Immunosuppressive Pure DNA Hydrogel

Effective modulation of persistent inflammation is crucial for chronic wound healing. However, the interaction cascade between inflammatory factors and immune cells at the soft-tissue wound interface poses an incredible challenge for this purpose. Here, we report an immunosuppressive pure DNA hydrogel (Is-pDNAgel) that reprograms inflammatory responses from both molecular and cellular dimensions. Specifically, high-density negative charges enable Is-pDNAgel to efficiently scavenge free chemokines, mitigating neutrophil and macrophage infiltration. Moreover, its immunosuppressive domain synergistically acts on activated residual immune cells and suppresses multiple proinflammatory signaling pathways, thereby creating a positive circuit to boost anti-inflammatory efficacy. Is-pDNAgel can further facilitate migration and proliferation of endogenous endothelial cells owing to its intrinsic extracellular matrix-mimicking structure, promoting re-epithelialization and neovascularization for tissue regeneration without additional bioactive components. Such an "all-in-one" hydrogel outperforms a commercial dressing to accelerate the healing of chronic wounds in a diabetic mouse model, offering a valuable tool for developing regenerative medicine.

Self-Healing Hydrogel Dressing with Solubilized Flavonoids for Whole Layer Regeneration of Diabetic Wound

Hydrogels are soft, tissue-like materials that have great potential as wound dressings. However, most hydrogels are unsatisfactory in achieving whole-layer regeneration of diabetic wounds due to the complex pathological microenvironment and irregular wound shapes. Here, a glucose-responsive and self-adaptive phenylboronic acid (PBA) hydrogel solubilized strong antioxidant flavonoids (Gel-Flavonoids) is developed via dynamic borate bonds. The Gel-Flavonoids system can spontaneously confirm to the irregular wound shape and release flavonoids in a high-glucose microenvironment to effectively eliminate reactive oxygen species (ROS). The optimized Gel-Flavonoids demonstrate remarkable efficacy in inhibiting inflammation and activating fibroblasts and endothelial cells through CD36-activated lipid metabolism in macrophages and is significantly superior to commercial dressings (3M) in healing rate (> 93%, 14 days) and whole-layer regeneration effect. This study obtained a multidimensional Gel-Flavonoids system to effectively repair diabetic wounds, and reveal the underlying therapeutic mechanisms, offering a promising insight to guide the development of medical materials to treat diabetic wounds.

A Smart MMP-9-responsive Hydrogel Releasing M2 Macrophage-derived Exosomes for Diabetic Wound Healing

Chronic diabetic wounds are characterized by prolonged inflammation and excessive accumulation of M1 macrophages, which impede the healing process. Therefore, resolving inflammation promptly and transitioning to the proliferative phase are critical steps for effective diabetic wound healing. Exosomes have emerged as a promising therapeutic strategy. In this study, a smart hydrogel capable of responding to pathological cues in the inflammatory microenvironment to promote the transition from inflammation to proliferation by delivering M2 macrophage-derived exosomes (M2-Exos) is developed. The smart hydrogel is synthesized through the cross-linking of oxidized dextran, a matrix metalloproteinase (MMP)-9-sensitive peptide, and carboxymethyl chitosan containing M2-Exos. In response to elevated MMP-9 concentrations in the inflammatory microenvironment, the hydrogel demonstrates diagnostic logic, adjusting the release kinetics of M2-Exos accordingly. The on-demand release of M2-Exos facilitated macrophage polarization from the M1 to the M2 phenotype, thereby promoting the transition from the inflammatory to the proliferative phase and accelerating diabetic wound healing. The transcriptomic analysis further reveals that the MMP-9-responsive hydrogel with M2-Exos delivery exerts anti-inflammatory and regenerative effects by downregulating inflammation-related pathways. This study introduces an innovative, microenvironment-responsive exosome delivery system that enables precise control of therapeutic agent release, offering a personalized approach for the treatment of chronic diabetic wounds.

Hydrogen bonding-mediated phase-transition gelatin-based bioadhesives to regulate immune microenvironment for diabetic wound healing

Gelatin-based biomaterials have emerged as promising candidates for bioadhesives due to their biodegradability and biocompatibility. However, they often face limitations due to the uncontrollable phase transition of gelatin, which is dominated by hydrogen bonds between peptide chains. Here, we developed controllable phase transition gelatin-based (CPTG) bioadhesives by regulating the dynamic balance of hydrogen bonds between the peptide chains using 2-hydroxyethylurea (HU) and punicalagin (PA). These CPTG bioadhesives exhibited significant enhancements in adhesion energy and injectability even at 4 °C compared to traditional gelatin bioadhesives. The developed bioadhesives could achieve self-reinforcing interfacial adhesion upon contact with moist wound tissues. This effect was attributed to HU diffusion, which disrupted the dynamic balance of hydrogen bonds and therefore induced a localized structural densification. This process was further facilitated by the presence of pyrogallol from PA. Furthermore, the CPTG bioadhesive could modulate the immune microenvironment, offering antibacterial, antioxidant, and immune-adjustable properties, thereby accelerating diabetic wound healing, as confirmed in a diabetic wound rat model. This proposed design strategy is not only crucial for developing controllable phase-transition bioadhesives for diverse applications, but also paves the way for broadening the potential applications of gelatin-based biomaterials.

Effect of different crosslinking agents on carboxymethyl chitosan-glycyrrhizic acid hydrogel: Characterization and biological activities comparison

Hydrogels were widely utilized in biomedical applications, with their mechanical properties and drug release behavior largely dependent on the type and degree of crosslinking. In this study, the effects of anhydrous ferrous chloride (Fe2+), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), and polyvinyl alcohol/borax (PVA/Borax) on the properties of carboxymethyl chitosan (CMCS) and glycyrrhizic acid (GA) hydrogels were investigated. The GA-CMCS-based hydrogels (GFC, GEDC, GPBC) were prepared and their Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and rheological properties were analyzed. The results showed that GFC excelled in self-healing, swelling, and water retention. Furthermore, hydrogels with varying GA concentrations crosslinked by Fe2+ were tested for antibacterial activity and cellular nitric oxide (NO) levels, and were compared to GEDC and GPBC. Notably, Fe2+-crosslinked hydrogels demonstrated significant antibacterial efficacy, the antibacterial rate of 3 % GFC reached 93 %. When compared to the LPS group, which had an inflammatory NO level of 30.58 ± 0.95 μM, the 3 % GFC group demonstrated a notable reduction to 12.88 ± 1.04 μM. In contrast, GEDC and GPBC showed limited antibacterial and anti-inflammatory properties. In brief, hydrogels' physical, chemical, and biological properties were notably affected by various crosslinking agents. This study provides valuable insights for designing hydrogels tailored to specific application requirements.

Multifunctional self-healing and pH-responsive hydrogel dressing based on cationic guar gum and hyaluronic acid for on-demand drug release

Pathogen invasion and persistent inflammatory storms caused by bacterial infections are the main challenges to the healing of infected wounds. Herein, this study proposed a pH-responsive polysaccharide hydrogel dressing (CG-HA) composed of cationic guar gum (CG) and hyaluronic acid (HA). Additionally, Zn2+ and ferulic acid (FA)/β-cyclodextrin (β-CD) inclusion complexes (FA/β-CD) were co-introduced into the CG-HA hydrogel to form the desired FA/β-CD@CG-HA-Zn hydrogel. The FA/β-CD@CG-HA-Zn hydrogel was constructed based on multiple non-covalent interactions, including electrostatic interactions, coordination bonds and hydrogen bonds, allowing it to conform to irregular wound shapes. Notably, the release rates of FA and Zn2+ at pH 7.5 were faster than those at pH 5.5, indicating that the FA/β-CD@CG-HA-Zn hydrogel exhibited excellent pH responsiveness and enabled intelligent drug release. Moreover, the inclusion of FA and Zn2+ endowed the hydrogel with robust antibacterial activity against S. aureus (97 %), MRSA (94 %), and E. coli (95 %). Finally, the FA/β-CD@CG-HA-Zn hydrogel demonstrated efficacy in promoting wound healing by modulating the immune microenvironment and accelerating vascularization. Thus, the developed self-healing FA/β-CD@CG-HA-Zn hydrogel with pH-triggered on-demand drug release is a promising wound dressing for the management of infected wounds.

Aggregation-induced emission-based phototheranostics to combat bacterial infection at wound sites: A review

The healing of chronic wounds infected by bacteria has attracted increasing global concerns. In the past decades, antibiotics have certainly brought hope to cure bacteria-infected chronic wounds. However, the misuse of antibiotics leads to the emergence of numerous multidrug-resistant bacteria, which aggravate the health threat to clinical patients. To address these increasing challenges, scientists are committed to creating novel non-antibiotic strategies to kill bacteria and promote bacteria-infected chronic wound healing. Fortunately, with the quick development of nanotechnology, the representatives of phototherapy, such as photothermal therapy (PTT) and photodynamic therapy (PDT), exhibit promising possibilities in promoting bacteria-infected wound healing. Well-known, photothermal agents and photosensitizers largely determine the effects of PTT and PDT. A common problem for these molecules is the aggregation-induced quenching effect, which highly limits their further applicability in biomedical and clinical fields. Fortunately, the occurrence of aggregation-induced emission luminogens (AIEgens) efficiently overcomes the photobleaching and exhibit advantages, such as strongly aggregated emission, superior photostability, aggregation-enhanced reactive oxygen species (ROS), and heat generation, which makes great sense to the development of PTT and PDT. This article reviews various studies conducted on novel AIEgen-based materials that can mediate potent PDT, PTT, and a combination of PDT and PTT to promote bacteria-infected chronic wound healing.

A Constant Filgotinib Delivery Adhesive Platform Based on Polyethylene Glycol (PEG) Hydrogel for Accelerating Wound Healing via Restoring Macrophage Mitochondrial Homeostasis

Skin wound healing is often hindered by disrupted mitochondrial homeostasis and imbalanced macrophage glucose metabolism, posing a critical challenge to improve patient outcomes. Developing new wound healing dressings capable of effectively regulating macrophage immune-metabolic functions remains a pressing issue. Herein, a highly adhesive polyethylene glycol (PEG) hydrogel loaded with the Janus kinase 1 (JAK1) inhibitor Filgotinib (Fil@GEL) is prepared to modulate macrophage metabolic reprogramming and restore normal mitochondrial function. Fil@GEL exhibits superior shear adhesion strength compared to commercially available tissue binder products, providing adequate adhesion for skin wound closure. Additionally, Fil@GEL exhibits the capacity to inhibit M1-type macrophage polarization by suppressing the JAK-STAT signaling pathway, and induces a metabolic shift in macrophages from aerobic glycolysis to oxidative phosphorylation, which results in decreased lactate production, reduced reactive oxygen species (ROS) levels, and the restoration of mitochondrial homeostasis. The Fil@GEL hydrogel significantly accelerates skin wound healing compared to the control group, reduces intra-wound inflammation, and promotes collagen regeneration. In summary, this highly adhesive hydrogel demonstrates exceptional performance as a drug carrier, exerting immunometabolic modulation through firm wound adhesion and sustained filgotinib release, underscoring its substantial potential as an effective wound dressing.

An injectable and adaptable system for the sustained release of hydrogen sulfide for targeted diabetic wound therapy by improving the microenvironment of inflammation regulation and angiogenesis

The combined effects of persistent chronic inflammation, oxidative stress, microcirculation disorders, and dysregulated cellular energy metabolism often hinder the repair of diabetic skin wounds. Traditional treatment methods are typically insufficient in simultaneously addressing these complex factors, resulting in delayed wound healing and a high propensity for recurrence and chronic ulceration. This study developed an innovative strategy based on reactive oxygen species (ROS)-responsive nanoparticles loaded with an ultraviolet (UV)-light-responsive hydrogen sulfide (H2S) donor. This approach leverages the endogenous ROS present in diabetic wounds and external UV light as dual triggers to facilitate the controlled and stepwise release of H2S. The material design explicitly targets the critical challenges in diabetic wound repair, including the inhibition of chronic inflammation, oxidative stress reduction, microcirculation improvement, and support of cellular energy metabolism, thereby significantly accelerating wound healing. This adaptive release of signaling molecules effectively modulates the wound regeneration microenvironment, enhancing the repair process and offering a promising solution for diabetic skin wound management. STATEMENT OF SIGNIFICANCE: This study developed an innovative strategy based on reactive oxygen species (ROS)-responsive nanoparticles loaded with an ultraviolet (UV)-light-responsive hydrogen sulfide (H2S) donor. This approach leverages the endogenous ROS present in diabetic wounds and external UV light as dual triggers to facilitate the controlled and stepwise release of H2S. The material design explicitly targets the critical challenges in diabetic wound repair, including the inhibition of chronic inflammation, oxidative stress reduction, microcirculation improvement, and support of cellular energy metabolism, thereby significantly accelerating wound healing. This adaptive release of signaling molecules effectively modulates the wound regeneration microenvironment, enhancing the repair process and offering a promising solution for diabetic skin wound management.