Facile General Injectable Gelatin/Metal/Tea Polyphenol Double Nanonetworks Remodel Wound Microenvironment and Accelerate Healing

Hydrogel adhesives for tissue recovery

Hydrogel adhesives (HAs) are promising and rewarding tools for improving tissue therapy management. Such HAs had excellent properties and potential applications in biological tissues, such as suture replacement, long-term administration, and hemostatic sealing. In this review, the common designs and the latest progress of HAs based on various methodologies are systematically concluded. Thereafter, how to deal with interfacial water to form a robust wet adhesion and how to balance the adhesion and non-adhesion are underlined. This review also provides a brief description of gelation strategies and raw materials. Finally, the potentials of wound healing, hemostatic sealing, controlled drug delivery, and the current applications in dermal, dental, ocular, cardiac, stomach, and bone tissues are discussed. The comprehensive insight in this review will inspire more novel and practical HAs in the future.

Engineering of Bioprosthetic Heart Valves with Synergistic Zwitterionic Surface Modification and Zirconium Cross-linking for Improved Biocompatibility and Durability

Bioprosthetic heart valves (BHVs) are frequently utilized in surgeries for heart valve replacement to address valvular heart disease (VHD). Despite their widespread use, BHVs still face challenges in clinical applications, such as thrombosis, calcification, immune responses, poor re-endothelialization, infection, component degradation, and mechanical failure, which are largely due to the heterogeneous cross-linking effects. To address these issues, we propose a synergistic engineering strategy based on sequential zwitterionic surface modification and zirconium cross-linking to improve the biocompatibility and durability of BHVs. After surface modification via ring-opening reactions of zwitterionic epoxy copolymers (PGSB) on collagen fibers of decellularized porcine pericardium (D-PP), the zwitterionic PGSB significantly promoted the uniform transfer of zirconium ions (Zr4+) and further coordinated with Zr4+ to achieve homogeneous cross-linking between collagen fibers. Compared to conventional glutaraldehyde (GA)-cross-linked PP, PGSB/Zr-PP showed enhanced anti-thrombotic performance, attenuated immune rejection, accelerated endothelialization, and over 95% reduction in calcification after 90 days of subcutaneous implantation, collectively indicating improved biocompatibility. Furthermore, this homogeneously cross-linked PGSB/Zr-PP exhibited undetectable component degradation and simultaneous improvements in both strength and toughness, all of which are essential for improving the durability of BHVs. Intriguingly, the zwitterionic sulfobetaine groups could be converted into bactericidal quaternary ammonium groups upon coordination with Zr4+, resulting in strong antibacterial and anti-biofilm activities beneficial for preventing life-threatening prosthetic valve endocarditis. More importantly, PGSB/Zr-PP met the ISO 5840-3 standards required for BHV applications in terms of hydrodynamic performance and 200-million-cycle durability. These results demonstrate that PGSB/Zr-PP would be a promising alternative to GA-cross-linked BHVs. STATEMENT OF SIGNIFICANCE: Mainstream glutaraldehyde-cross-linked BHV face persistent clinical challenges, including thrombosis, calcification, immune response, poor re-endothelialization, infection, component degradation, and mechanical failure. Although various non-glutaraldehyde cross-linkers have been investigated, few strategies effectively address these challenges due to the heterogeneous nature of cross-linking. Herein, we present a synergistic engineering strategy based on sequential zwitterionic surface modification and zirconium cross-linking. This strategy produces homogeneously cross-linked BHVs with comprehensive improvements in anti-thrombogenicity, immune compatibility, endothelialization, resistance to calcification and infection, enzymatic stability, and mechanical strength. Notably, the aortic BHV fabricated via this method met the ISO 5840-3 standards for hydrodynamic performance and durability, demonstrating its long-term clinical potential.

Multifunctional injectable hydrogel incorporating EGCG-Cu complexes for synergistic antibacterial, immunomodulatory, and osteogenic therapy in periodontitis

Periodontitis is a chronic inflammatory disease characterized by oxidative stress, immune system imbalance, and the progressive destruction of periodontal tissues. Traditional treatment approaches are limited by the incomplete eradication of pathogens, the risk of antibiotic resistance, inadequate control of inflammation and oxidative stress, and restricted tissue regeneration capacity. Therefore, this study proposes an injectable multifunctional Laponite/gelatin hydrogel loaded with epigallocatechin gallate (EGCG)-copper ion (Cu2+) complexes as a localized therapy for periodontitis. EGCG exhibits antioxidant, anti-inflammatory, and antimicrobial properties; however, its clinical application is hindered by poor stability and bioavailability. Cu2+ coordination enhances EGCG stability and antioxidant capacity while improving its antimicrobial efficacy. Experimental results demonstrate that the Laponite/gelatin hydrogel is adaptable for the localized delivery of EGCG-Cu, with bioactive metal ions such as Li+, Mg2+, and Si4+ contained in Laponite, which promote osteogenesis and periodontal tissue regeneration. In vitro and in vivo studies confirm that this hydrogel exhibits excellent biocompatibility, effectively inhibits Porphyromonas gingivalis, suppresses M1 polarization while promoting M2 polarization, and facilitates periodontal tissue repair. Therefore, this study provides promising insights into a localized therapeutic strategy for periodontitis.

Biodegradable Cellulose Acetate Nanofibrous Membranes with Self-Sustaining Electrostatic Effect for Efficient and Stable Air Purification

Amid the global pursuit of carbon neutrality and the pressing challenge of severe air pollution, degradable cellulose acetate (CA) materials hold great potential in the field of air filtration. However, their weak polarity and poor antibacterial properties limit their widespread application in this field. Herein, we developed CA-based nanofibrous membranes (CAPZ NFMs) with antimicrobial properties, which achieved efficient and stable filtration performance through a self-sustaining electrostatic effect driven by polarity. CAPZ NFMs were fabricated by electrospinning a solution that contained CA, highly polar zwitterionic copolymers (PSG), and biocompatible Zr4+. The zwitterionic groups of PSG increased the polarity of CAPZ NFMs to 19.62 mN·m-1, significantly surpassing that of pristine CA NFMs (2.94 mN·m-1). This enhancement granted CAPZ NFMs a surface potential of 2.07 kV, which enabled a PM0.3 filtration efficiency of 99.56% while maintaining a low pressure drop of 79 Pa. Notably, CAPZ NFMs maintained superior performance under high humidity conditions and 6 months of outdoor storage. Additionally, Zr4+ coordinated with the zwitterionic groups of PSG to form quaternary ammonium groups, endowing CAPZ NFMs with broad-spectrum antibacterial efficacy of over 99.99%. This work could provide new strategies for developing next-generation biodegradable, high-electrostatic filtration materials.

Proanthocyanidin capsules remodel the ROS microenvironment via regulating MAPK signaling for accelerating diabetic wound healing

Defective diabetic wound healing is a major clinical challenge, where hyperglycemia at the wound site induces excessive reactive oxygen species (ROS) which activate the MAPK pathway (particularly p38 MAPK), resulting in sustained release of inflammatory factors and cellular damage/apoptosis. Polyphenols are efficient ROS scavengers which reduce the level of inflammation at the wound site and promote wound healing, but the low bioavailability limits their biomedical application. This study developed a simple and highly efficient method for preparing proanthocyanidin (PC) capsules through hydrogen bonding and hydrophobic interactions among PC molecules. PC capsules can continuously scavenge free radicals and release proanthocyanidins, significantly enhancing their bioavailability. A single dose of PC capsules accelerates wound healing in diabetic mice by regulating the p38 MAPK signaling cascade, reducing inflammatory mediator concentration, inhibiting cell apoptosis, and remodeling the wound microenvironment. This research makes an important contribution to the field of enhancing polyphenol bioavailability for wound healing and reveals the potential of modulating the MAPK pathway for treating other inflammation and oxidative stress-related diseases.

Acteoside-Loaded Self-Healing Hydrogel Enhances Skin Wound Healing through Modulation of Hair Follicle Stem Cells

Background

Skin wound healing is a complex biological process involving cellular, molecular, and physiological events. Traditional treatments often fail to provide optimal outcomes, particularly for chronic wounds.

Objectives

This study aimed to develop a self-healing hydrogel loaded with Acteoside, a bioactive compound with antioxidant and anti-inflammatory properties, to enhance skin wound healing.

Methods

Using transcriptomic analysis, Rab31 was identified as a key target of Acteoside in regulating hair follicle stem cells (HFSCs). In vitro assays demonstrated that Acteoside promotes HFSC proliferation, migration, and differentiation by upregulating Rab31 expression. The self-healing hydrogel was prepared using quaternized chitosan derivatives, which exhibited excellent mechanical properties, antibacterial, and antioxidant activities.

Results

In vivo studies in a mouse model showed that Acteoside-loaded hydrogel significantly accelerated wound healing, promoting skin regeneration and improving wound closure.

Conclusions

This research highlights the potential of Acteoside-loaded self-healing hydrogels as an innovative therapeutic strategy for enhancing skin wound healing. By modulating HFSC activity, this hydrogel offers a promising solution for improving healing outcomes in challenging wound environments.

Graphical Abstract

Schematic representation of an injectable self-healing hydrogel loaded with the phenylethanoid compound acteoside for regulating the proliferation and differentiation of HFSCs to mediate the healing of skin wounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-025-00845-2.

Polyphenols in wound healing: unlocking prospects with clinical applications

Wound healing is a multifaceted, complex process that factors like aging, metabolic diseases, and infections may influence. The potentiality of polyphenols, natural compounds, has shown anti-inflammatory and antimicrobial properties in promoting wound healing and their potential applications in wound management. The studies reviewed indicate that polyphenols have multiple mechanisms that promote wound healing. This involves enhancing antioxidant defenses, reducing oxidative stress, modulating inflammatory responses, improving healing times, reducing infection rates, and enhancing tissue regeneration in clinical trials and in vivo and in vitro studies. Polyphenols have been proven to be effective in managing hard-to-heal wounds, especially in diabetic and elderly populations. Polyphenols have shown significant benefits in promoting angiogenesis and stimulating collagen synthesis. Polyphenol treatment has been demonstrated to have therapeutic effects in wound healing and chronic wound management. Their ability to regulate key healing processes makes them suitable for new wound care products and treatments. Future research should enhance formulations and delivery methods to optimize polyphenols' bioavailability and therapeutic efficacy in wound management approaches.

Design and advances in antioxidant hydrogels for ROS-induced oxidative disease

Reactive oxygen species (ROS) play a crucial role in human physiological processes, but oxidative stress caused by excessive ROS may lead to a variety of acute and chronic diseases. Despite the development of various strategies and biomaterials, an efficiently and broadly applied method for treatment of ROS-induced oxidative disease remains a bottleneck. Aiming to improve the local oxidative stress environment, numerous bioactive hydrogels with antioxidant properties have emerged and are proven to quickly and continuously eliminate excessive ROS. To deeply understand the design principles and applications of antioxidant hydrogels is highly beneficial for designing antioxidant hydrogels for treatment of oxidative disease. This review provides a detailed summary of recent advances in design and applications of antioxidant hydrogels for various ROS-induced oxidative diseases. In this review, the kinds of antioxidant components in antioxidant hydrogels are outlined in detail. Additionally, the crosslinking methods and the biomedical applications of antioxidant hydrogels are widely summarized and discussed, especially focusing on their usage in different types of diseases and the attention given to the treatment of diseases such as skin wounds, myocardial infarction, and osteoarthritis. Finally, the future development direction of antioxidant hydrogel is further proposed. STATEMENT OF SIGNIFICANCE: Oxidative stress is a pivotal biochemical process that plays a critical role in cellular homeostasis. Excessive cellular oxidative stress triggers an inflammatory response, which is implicated in a spectrum of associated diseases. Given the critical need for managing oxidative stress, antioxidant therapies have become a vital focus in medical research. Hydrogels have garnered substantial interest among biomaterial scientists due to their hydrophilic nature and biocompatibility. The review delves into the realm of antioxidant hydrogels, encompassing the classification of antioxidant components, the synthesis and fabrication of hydrogels, and a comprehensive overview of the biological applications and challenges of these antioxidant hydrogels. Aiming to provide new perspectives for researchers in developing cutting-edge therapeutic approaches that leverage antioxidant hydrogels.

Metal-Protein Hybrid Materials: Unlocking New Frontiers in Biomedical Applications

Metal-protein hybrid materials represent a novel class of functional materials that exhibit exceptional physicochemical properties and tunable structures, rendering them remarkable applications in diverse fields, including materials engineering, biocatalysis, biosensing, and biomedicine. The design and development of multifunctional and biocompatible metal-protein hybrid materials have been the subject of extensive research and a key aspiration for practical applications in clinical settings. This review provides a comprehensive analysis of the design strategies, intrinsic properties, and biomedical applications of these hybrid materials, with a specific emphasis on their potential in cancer therapy, drug and vaccine delivery, antibacterial treatments, and tissue regeneration. Through rational design, stable metal-protein hybrid materials can be synthesized using straightforward methods, enabling them with therapeutic, delivery, immunomodulatory, and other desired functionalities. Finally, the review outlines the existing limitations and challenges associated with metal-protein hybrid materials and evaluates their potential for clinical translation, providing insights into their practical implementation within biomedical applications.

Engineered Living Systems Based on Gelatin: Design, Manufacturing, and Applications

Engineered living systems (ELSs) represent purpose-driven assemblies of living components, encompassing cells, biomaterials, and active agents, intricately designed to fulfill diverse biomedical applications. Gelatin and its derivatives have been used extensively in ELSs owing to their mature translational pathways, favorable biological properties, and adjustable physicochemical characteristics. This review explores the intersection of gelatin and its derivatives with fabrication techniques, offering a comprehensive examination of their synergistic potential in creating ELSs for various applications in biomedicine. It offers a deep dive into gelatin, including its structures and production, sources, processing, and properties. Additionally, the review explores various fabrication techniques employing gelatin and its derivatives, including generic fabrication techniques, microfluidics, and various 3D printing methods. Furthermore, it discusses the applications of ELSs based on gelatin in regenerative engineering as well as in cell therapies, bioadhesives, biorobots, and biosensors. Future directions and challenges in gelatin fabrication are also examined, highlighting emerging trends and potential areas for improvements and innovations. In summary, this comprehensive review underscores the significance of gelatin-based ELSs in advancing biomedical engineering and lays the groundwork for guiding future research and developments within the field.

Facile Formulation of a Resveratrol-Mediated Multibond Network Hydrogel with Efficient Sustainable Antibacterial, Reactive Oxygen Species Scavenging, Pro-Angiogenesis, and Immunomodulation Activities for Accelerating Infected Wound Healing

The management of chronic infected wounds remains a significant clinical challenge, largely due to the deficiency of optimal wound dressings with adequate mechanical strength, appropriate adhesiveness, and efficient sustainable antibacterial, reactive oxygen species (ROS) scavenging, pro-angiogenesis, and immunomodulation properties. To address such a dilemma, we employed a simple and facile strategy to utilize resveratrol (RSV) as a functional component to mediate hydrogel gelation in this study. The structure of this obtained hydrogel was supported by a multibond network, which not only endowed the resultant product with superior mechanical strength and moderate adhesiveness but also effectively prolonged the bioavailability of RSV. This strategy successfully integrated the entire system with sustainable antibacterial, ROS scavenging, pro-angiogenesis, and immunomodulation properties. Subsequent in vivo evidence has verified that this material was capable to accelerate the healing of chronic infected wounds. The underlying mechanism can be explained that this hydrogel is capable of propelling macrophage polarization from the M1 to M2 phenotype through modulating the PI3K/AKT signaling pathway to activate the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling as well as maintaining the mitochondrial membrane potential level in the normal state under excessive inflammatory and oxidative stimulus. In summary, this multifunctional hydrogel wound dressing provides a feasible way to promote the bioavailability of RSV, which is conducive for preparing a promising candidate for chronic infected wound healing. What is more important, it is also beneficial to reveal the correlative mechanisms to establish advanced therapeutic platform for targeting other complex infection microenvironment.

Microglial DBP Signaling Mediates Behavioral Abnormality Induced by Chronic Periodontitis in Mice

Several lines of evidence implicate that chronic periodontitis (CP) increases the risk of mental illnesses, such as anxiety and depression, yet, the associated molecular mechanism for this remains poorly defined. Here, it is reported that mice subjected to CP exhibited depression-like behaviors and hippocampal memory deficits, accompanied by synapse loss and neurogenesis impairment in the hippocampus. RNA microarray analysis disclosed that albumin D-site-binding protein (DBP) is identified as the most prominently upregulated target gene following CP, and in vivo and in vitro immunofluorescence methods showed that DBP is preferentially expressed in microglia but not neurons or astrocytes in the hippocampus. Interestingly, it is found that the expression of DBP is significantly increased in microglia after CP, and knockdown of microglial DBP ameliorated the behavioral abnormality, as well as reversed the synapse loss and hippocampal neurogenesis damage induced by CP. Furthermore, DBP knockdown improved the CP-induced hippocampal inflammation and microglial polarization. Collectively, these results indicate a critical role of DBP in orchestrating chronic periodontitis-related behavioral abnormality, hippocampal synapse loss and neurogenesis deficits, in which the microglial activation may be indispensably involved.

Multiple-Effect Combined Hydrogels: "Temporal Regulation" Treatment of Osteosarcoma-Associated Bone Defects with Switchable Hyperthermia and Bioactive Agents

Achieving the clinically staged treatment of osteosarcoma-associated bone defects encounters the multiple challenges of promptly removing postoperative residual tumor cells and bacterial infection, followed by bone reconstruction. Herein, a core/shell hydrogel with multiple-effect combination is designed to first exert antitumor and antibacterial activities and then promote osteogenesis. Specifically, doxorubicin (DOX) is loaded by magnesium-iron-based layered double hydroxide (LDH) to prepare LDOX, which is introduced into a thermo-sensitive hydrogel to serve as an outer shell of the core/shell hydrogel, meanwhile, LDH-contained liquid crystal hydrogel, abbreviated as LCgel-L, is served as an inner core. At the early stage of treatment, the dissociation of the outer shell triggered by moderate hyperthermia led to the thermo-sensitive release of LDOX, which can be targeted for the release of DOX within tumor cells, thereby promptly removing postoperative residual tumor cells based on the synergistic effect of photothermal therapy (PTT) and DOX, and postoperative bacterial infection can also be effectively prevented by PTT simultaneously. More importantly, the dissociation of the outer shell prompted the full exposure of the inner core, which will exert osteogenic activity based on the synergy of liquid crystal hydrogel as well as LDH-induced mild hyperthermia and ion effects, thereby enabling "temporal regulation" treatment of osteosarcoma-associated bone defects. This study provides a valuable insight for the development of osteosarcoma-associated bone repair materials.

Chondroitin sulfate sponge scaffold for slow-release Mg2+/Cu2+ in diabetic wound management: Hemostasis, effusion absorption, and healing

The management of diabetic wounds presents significant challenges due to persistent inflammation, microenvironmental disruptions, and impaired angiogenesis. To address these issues, this study developed a multifunctional chondroitin sulfate sponge (CSP@Cu-Mg) with anti-inflammatory properties, hemostatic effects, effusion absorption, and enhanced healing promotion. Through ion crosslinking, MgO and CuO were incorporated into the interpenetrating network structure of chondroitin sulfate and acellular dermal matrix, resulting in a sponge with impressive liquid absorption capacity (3450 %) and porosity (83 %). This sponge enabled sustained release of Mg2+/Cu2+ ions, with approximately 40 % cumulative release over 7 days. This release helped reduce inflammation, promote the proliferation and migration of skin repair-related cells, and stimulate angiogenesis. In vivo studies demonstrated that the CSP@Cu-Mg sponge significantly improved diabetic wound healing by modulating inflammation and accelerating collagen deposition, angiogenesis, and re-epithelialization. This extracellular matrix sponge, which synergistically releases Mg2+/Cu2+, presents a promising strategy for comprehensive diabetic wound management with substantial clinical implications.

Injectable and self-healable hydrogel based on pullulan polysaccharide loading platelet-rich plasma and metal-phenol network nanoparticles for infectious wound healing

Due to elevated glucose levels, oxidative stress, weakened immune function, and delayed angiogenesis, diabetic wounds are difficult to heal. However, current dressings often do not successfully achieve the desired therapeutic outcome for diabetic wounds. Platelet rich plasma (PRP) is widely used in the treatment of diabetic wounds. Even so, the sudden release of growth factors or proteins in PRP frequently hampers the therapeutic efficacy. Therefore, it is of considerable clinical value to achieve long-term release of active molecules in PRP and to create more effective diabetic wound dressings. Here, PRP was combined with pullulan polysaccharide derivatives (OPD) and polylysine derivatives (EPL-BA) to form a multifunctional hydrogel backbone. Tea polyphenols (TP), gallic acid (GA), and metal ions (Cu2+) were utilized to prepare metal-phenol network nanoparticles (TGMPN) which were encapsulated in the hydrogel system. The EPL-BA/OPD/PRP/TGMPN (EOPM) composite hydrogel showed injectable and self-healing properties. The hydrogel system could effectively remove reactive oxygen species (ROS) and showed excellent antibacterial properties against different bacteria. The results showed that EOPM hydrogel was effective in reducing the inflammatory response and promoting the regeneration of blood vessels and neoplastic tissues, thus greatly accelerating the repair of infected wounds.

Controllable self-assembly of double polyphenol-metal-network: A universal gravel-like lignin catalysts for water purification

Lignin has attracted wide attention in sustainable environment remediation, especially the polyphenol-metal-network (PMN) based on lignin that shows unique applicability. In this work, by self-assembly of double PMN formed by lignin, plant tannins (TA) and Fe ions, a universal gravel-like lignin catalysts were reported for cost-efficient water purification. A controllable self-assembly technique dependent in pH was developed, achieving the controllable synthesis of materials with highly uniformity. Driven by strong multiple intermolecular interactions and PMN mediated TA-Fe Fenton system, this bio-based material exhibited efficient interfacial capture (65.70 mg·g-1) and in-situ degradation performance (95.40 %), and removed ubiquitous dye contaminants through static and flowing operation. Benefiting from this, effective flowing purify platform that continuously purify large-scale dye-containing wastewater through flowthrough strategy was profiled, confirming the potential in real industrial system. The theoretical calculations including molecular dynamics simulation contributed to providing insightful comprehension for co-assembly of system and their intermolecular interaction with dye molecules. Additionally, this material also showed magnetic response ability, stable reusability performance, and extended preparation advantages. This work provided a facile strategy to develop advanced lignin-based double PMN derived materials to support water purification by utilizing solid-waste to repair liquid-waste.

Microorganism microneedle micro-engine depth drug delivery

As a transdermal drug delivery method, microneedles offer minimal invasiveness, painlessness, and precise in-situ treatment. However, current microneedles rely on passive diffusion, leading to uncontrollable drug penetration. To overcome this, we developed a pneumatic microneedle patch that uses live Enterobacter aerogenes as microengines to actively control drug delivery. These microbes generate gas, driving drugs into deeper tissues, with adjustable glucose concentration allowing precise control over the process. Our results showed that this microorganism-powered system increases drug delivery depth by over 200%, reaching up to 1000 μm below the skin. In a psoriasis animal model, the technology effectively delivered calcitriol into subcutaneous tissues, offering rapid symptom relief. This innovation addresses the limitations of conventional microneedles, enhancing drug efficiency, transdermal permeability, and introducing a creative paradigm for on-demand controlled drug delivery.

Current progress of protein-based dressing for wound healing applications - A review

Protein-based wound dressings have garnered increasing interest in recent years owing to their distinct physical, chemical, and biological characteristics. The intricate molecular composition of proteins gives rise to unique characteristics, such as exceptional biocompatibility, biodegradability, and responsiveness, which contribute to the promotion of wound healing. Wound healing is an intricate and ongoing process influenced by multiple causes, and it consists of four distinct phases. Various treatments have been developed to repair different types of skin wounds, thanks to advancements in medical technology and the recognition of the diverse nature of wounds. This review has literature reviewed within the last 3-5 years-the recent progress and development of protein in wound dressings and the fundamental properties of an ideal wound dressing. Herein, the recent strides in protein-based state-of-the-art wound dressing emphasize the significant challenges and summarize future perspectives for wound healing applications.

3D Printing of Naturally Derived Adhesive Hemostatic Sponge

Hydrogel hemostatic sponges have been recognized for its effectiveness in wound treatment due to its excellent biocompatibility, degradability, as well as multi-facet functionalities. Current research focuses on optimizing the composition and structure of the sponge to enhance its therapeutic effectiveness. Here, we propose an adhesive hydrogel made from purely natural substances extracted from okra and Panax notoginseng. We utilize 3-dimensional (3D) printing technology to fabricate the hemostatic hydrogel scaffold, incorporating gelatin into the hydrogel and refining the mixing ratio. The interaction between gelatin and okra polyphenols contributes to successful injectability as well as stability of the printed scaffold. The okra in the scaffold exhibits favorable adhesion and hemostatic effects, and the total saponins of Panax notoginseng facilitate angiogenesis. Through in vitro experiments, we have substantiated the scaffold's excellent stability, adhesion, biocompatibility, and angiogenesis-promoting ability. Furthermore, in vivo experiments have demonstrated its dual functionality in rapid hemostasis and wound repair. These features suggest that the 3D-printed, natural substance-derived hydrogel scaffolds have valuable potential in wound healing and related applications.

Glucose-responsive, self-healing, wet adhesive and multi-biofunctional hydrogels for diabetic wound healing

Diabetic wounds are serious clinical complications which manifest wet condition due to the mass exudate, along with disturbed regulation of inflammation, severe oxidative stress and repetitive bacterial infection. Existing treatments for diabetic wounds remain unsatisfactory due to the lack of ideal dressings that encompass mechanical performance, adherence to moist tissue surfaces, quick repair, and diverse therapeutic benefits. Herein, we fabricated a wet adhesive, self-healing, glucose-responsive drug releasing hydrogel with efficient antimicrobial and pro-healing properties for diabetic wound treatment. PAE hydrogel was constructed with poly(acrylic acid-co-acrylamide) (AA-Am) integrated with a dynamic E-F crosslinker, which consisted of epigallocatechin gallate (EGCG) and 4-(2-acrylamidoethylcarbamoyl)-3-fluorophenylboronic acid (AFPBA). Due to the dynamic crosslinking nature of boronate esters, abundant catechol groups and hydrogen bonding, PAE hydrogel demonstrated excellent mechanical properties with about 1000 % elongation, robust adhesion to moist tissues, fast self-healing, and absorption of biofluids of 10 times of its own weight. Importantly, PAE hydrogel exhibited sustained and glucose-responsive release of EGCG. Together, the bioactive PAE hydrogel had effective antibacterial, antioxidative, and anti-inflammatory properties in vitro, and accelerated diabetic wound healing in rats via reducing tissue-inflammatory response, enhancing angiogenesis, and reprogramming of macrophages. Overall, this versatile hydrogel provides a straightforward solution for the treatment of diabetic wound, and shows potential for other wound-related application scenarios.

Poly(ionic liquid)-Flocculated Chlorella Loading Bactericidal and Antioxidant Hydrogel as a Biological Hydrogen Therapy for Diabetic Wound Dressing

Infection and oxidative stress seriously hinder the healing of diabetic wounds, resulting in various serious health and clinical problems. Herein, a sustainable biological hydrogen (H2)-producing hyaluronic acid-based hydrogel patch (HAP-Chl) was constructed by loading an imidazolium-based poly(ionic liquid) (PIL) flocculated live Chlorella as a diabetic wound dressing. The PIL can flocculate Chlorella through electrostatic interactions between PIL and Chlorella to form Chlorella agglomerates, endowing the Chlorella in the central agglomerates with the ability to continuously produce H2 for 24 h under mild conditions. Combining the membrane disruption-related bactericidal mechanism of PIL and the antioxidant properties of the produced H2, HAP-Chl was determined to be antibacterial and antioxidant. In addition to exhibiting biocompatible and nontoxic activities, subsequent Staphylococcus aureus-infected chronic wound studies revealed that HAP-Chl is capable of promoting the healing of chronic wounds by effectively killing bacteria, reducing extensive ROS, relieving inflammation, and promoting the deposition of mature collagen and angiogenesis. This study provides a new strategy for constructing an in situ sustainable H2-producing hydrogel, enabling the formation of novel antibacterial and antioxidant material platforms with potential for wound dressing applications.

A dual network cross-linked hydrogel with multifunctional Bletilla striata polysaccharide/gelatin/tea polyphenol for wound healing promotion

Wound healing is a dynamic and complex biological process, and traditional biological excipients cannot meet the needs of the wound healing process, and there is an urgent need for a biological dressing with multifunctionality and the ability to participate in all stages of wound healing. This study developed tea polyphenol (TP) incorporated multifunctional hydrogel based on oxidized Bletilla striata polysaccharide (OBSP) and adipic acid dihydrazide modified gelatin (Gel-ADH) with antimicrobial, antioxidant hemostatic, and anti-inflammatory properties to promote wound healing. The composite OBSP, Gel-ADH, TP (OBGTP) hydrogels prepared by double crosslinking between OBSP, TP and Gel-ADH via Schiff base bonding and hydrogen bonding had good rheological and swelling properties. The introduction of TP provided the composite hydrogel with excellent antioxidant antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coil). In the rat liver hemorrhage model and skin injury model, the OBGTP composite hydrogel had significant (p < 0.001) hemostatic ability, and had the ability to accelerate collagen deposition, reduce the expression of inflammatory factors, and promote rapid wound healing. In addition, OBGTP hydrogels had adhesive properties and good biocompatibility. In conclusion, OBGTP multifunctional composite hydrogels have great potential for wound healing applications.

ROS Balance Autoregulating Core-Shell CeO2@ZIF-8/Au Nanoplatform for Wound Repair

Reactive oxygen species (ROS) plays important roles in living organisms. While ROS is a double-edged sword, which can eliminate drug-resistant bacteria, but excessive levels can cause oxidative damage to cells. A core-shell nanozyme, CeO2@ZIF-8/Au, has been crafted, spontaneously activating both ROS generating and scavenging functions, achieving the multi-faceted functions of eliminating bacteria, reducing inflammation, and promoting wound healing. The Au Nanoparticles (NPs) on the shell exhibit high-efficiency peroxidase-like activity, producing ROS to kill bacteria. Meanwhile, the encapsulation of CeO2 core within ZIF-8 provides a seal for temporarily limiting the superoxide dismutase and catalase-like activities of CeO2 nanoparticles. Subsequently, as the ZIF-8 structure decomposes in the acidic microenvironment, the CeO2 core is gradually released, exerting its ROS scavenging activity to eliminate excess ROS produced by the Au NPs. These two functions automatically and continuously regulate the balance of ROS levels, ultimately achieving the function of killing bacteria, reducing inflammation, and promoting wound healing. Such innovative ROS spontaneous regulators hold immense potential for revolutionizing the field of antibacterial agents and therapies.

Gelatin-based dynamic response antioxidant, anti-inflammatory multifunctional hydrogel for enhanced diabetic wound repair

Diabetic wound therapy presents significant challenges in the clinical environment, where persistent bleeding, disturbed inflammatory regulation, impaired cellular proliferation, and impaired tissue remodeling are major features of diabetic wound healing. However, current treatment strategies need to be considered in the context of the dynamic and complex needs of chronic wound healing. Here, multifunctional dynamic boronic acid cross-linked hydrogels were prepared by the reaction of gelatin (Gel) inoculated with 5-carboxy 3-nitrophenylboronic acid (NPBA) and Epigallocatechin gallate (EGCG) to achieve rapid gelation at pH = 7.4, EGCG could interact electrostatically with cationic antimicrobial peptides (AMP) to achieve the effective loading of AMP in the hydrogels. This hydrogel can be injected and adhered to skin defects in diabetic patients to provide a barrier and rapid hemostasis. In a high glucose microenvironment, the rapid release of AMP effectively kills bacteria, while the responsive release of EGCG eliminates reactive oxygen species (ROS) and promotes macrophage M2 polarization. In addition, the hydrogel had excellent biocompatibility and degradability properties, degraded completely after 3 days of subcutaneous injection, and was non-toxic in H&E staining of major organs and serum liver function indices in mice. This multifunctional injectable hydrogel accelerates diabetic skin wound repair and is a promising dressing for the precise treatment of diabetic wounds.