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

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.

Facile preparation of carboxymethyl chitosan/dextran/poly(ionic liquid)-based hydrogel with intrinsic antibacterial and antioxidant properties for accelerating skin wound healing

Bleeding, bacterial infections and inflammation of skin open wounds are still threat to the public. Traditional wound dressings lost their adaptability to wound shape and lack of therapeutic effects. Herein, the composite POCP hydrogel was prepared by introducing poly(ionic liquids)-poly(1-butyl-3-vinylimidazolium gluconate) with gluconate as the counter ion into a phenylboronic acid group-grafted carboxymethyl chitosan and oxidized dextran-based hydrogel for promoting skin wound healing. The dynamic Schiff base and borate ester crosslinks constructed the gel networks, which gives POCP excellent self-healing ability and thus being beneficial for adapting to wound shape. The poly(ionic liquids) matrix not only effectively enhanced the mechanical properties and antibacterial abilities of the hydrogel, but also endowed the hydrogel with good radical scavenging capacity. POCP also exhibited good adhesiveness towards different tissues and could effectively stop tissue bleeding. Through an in vivo skin defect model, this biocompatible POCP could accelerate wound closure and promote tissue regeneration by relieving inflammatory responses and facilitating angiogenesis. This work provides an effective drug-free strategy to prepare hydrogel dressings with multi-intrinsic properties for clinical wound management.

Dual-network hydrogel loaded with antler stem cells conditioned medium and EGCG promotes diabetic wound healing through antibacterial, antioxidant, anti-inflammatory, and angiogenesis

Diabetic wound healing is characterized by persistent inflammation, reactive oxygen species overproduction, bacterial infection, and compromised angiogenesis. In recent years, Antler Stem Cells (ASCs) have attracted attention because of their potential role in promoting wound healing by promoting cell proliferation and angiogenesis via paracrine effects. In addition, epigallocatechin gallate (EGCG), the main component of green tea, exhibits antibacterial, anti-inflammatory, and antioxidant properties. In this study, we designed and fabricated a gelatin (G)/sodium alginate (SA)-based (SA/G) dual-network hydrogel loaded with ASC-derived conditioned medium (ASC-CM) and EGCG (CEGA) that exhibited excellent swelling capacity, sustained release, and mechanical properties. Both in vitro and in vivo experiments demonstrated that CEGA hydrogels were capable of enhancing cell proliferation, promoting angiogenesis, exhibiting antibacterial properties, mitigating inflammation, and regulating macrophage polarization. These results substantiate their potential application as novel dressings for healing diabetic skin wounds.

Engineered MXene Biomaterials for Regenerative Medicine

MXene-based materials have attracted significant interest due to their distinct physical and chemical properties, which are relevant to fields such as energy storage, environmental science, and biomedicine. MXene has shown potential in the area of tissue regenerative medicine. However, research on its applications in tissue regeneration is still in its early stages, with a notable absence of comprehensive reviews. This review begins with a detailed description of the intrinsic properties of MXene, followed by a discussion of the various nanostructures that MXene can form, spanning from 0 to 3 dimensions. The focus then shifts to the applications of MXene-based biomaterials in tissue engineering, particularly in immunomodulation, wound healing, bone regeneration, and nerve regeneration. MXene's physicochemical properties, including conductivity, photothermal characteristics, and antibacterial properties, facilitate interactions with different cell types, influencing biological processes. These interactions highlight its potential in modulating cellular functions essential for tissue regeneration. Although the research on MXene in tissue regeneration is still developing, its versatile structural and physicochemical attributes suggest its potential role in advancing regenerative medicine.

An adhesive and self-healing ROS-scavenging hydrogel loading with hMSC-derived exosomes for diabetic wound healing

Diabetic wounds have garnered significant attention due to excessive reactive oxygen species (ROS), persistent inflammation, and vascular and neural impairments that hinder effective healing. ROS-scavenging hydrogels with phenylborate bonds possess inherent anti-ROS and anti-inflammatory properties, while human mesenchymal stem cell-derived exosomes (hMSC-exos) offer additional anti-inflammatory, pro-angiogenic, and neurogenic benefits, presenting a promising strategy to address these challenges. This study introduces a novel ROS-scavenging hydrogel loaded with hMSC-exos, which exhibits strong adhesion and self-healing capabilities. Upon application to the wound, it interacts with ROS to produce an anti-inflammatory response, concurrently allowing a sustained release of hMSC-exos. In vitro and in vivo experiments have demonstrated that this hydrogel effectively reduces ROS levels, mitigates inflammation, and promotes angiogenesis and neurogenesis, thus enhancing functional skin restoration and accelerating wound healing. In summary, we propose an innovative therapeutic approach for diabetic wound healing by combining ROS-scavenging hydrogels with hMSC-exos, with the potential to significantly benefit patients.

Responsive hydrogel modulator with self-regulated polyphenol release for accelerating diabetic wound healing via precise immunoregulation

Nonhealing chronic wounds are intractable clinical complications of diabetes and are characterized by high protease activity, severe oxidative stress and sustained inflammatory response. In this case, the development of functional hydrogel dressings to modulate the immune microenvironment is a well-known strategy, where the precise stimuli-responsive and spatiotemporally controlled release of bioactive molecules remains a huge challenge. Herein, we developed responsive hydrogels with self-regulated bioactive molecule release based on the protease activity in diabetic wound sites, to serve as a smart immune microenvironment modulator for accelerating wound healing. The hydrogels were fabricated by grafting oxidized hyaluronic acid with epigallocatechin-3-gallate (EGCG) and gelatin methacryloyl (GelMA) under UV irradiation. Resveratrol nanoparticles were further loaded into the hydrogels before gelation to construct a polyphenol delivery system. The prepared hydrogels could achieve the on-demand release of polyphenol upon degradation by protease, as confirmed via degradation and polyphenol release experiments. The released polyphenol was demonstrated to have the capacity to effectively scavenge excessive free radicals, promote macrophage polarization, reduce proinflammatory factor (TNF-α) expression and augment anti-inflammatory factor (IL-10) expression in vitro. Additionally, in vivo rat wound healing model experiment results confirmed that these hydrogels promoted collagen deposition and granulation tissue regeneration, accelerating diabetic wound healing. Based on the protease-responsive degradation characteristic of the hydrogels and high protease activity in the diabetic wound microenvironment, hydrogels with exquisite polyphenol release controllability are promising candidates as dressings for diabetic wound management.

An active shrinkage and antioxidative hydrogel with biomimetic mechanics functions modulates inflammation and fibrosis to promote skin regeneration

Achieving scar-free skin regeneration in clinical settings presents significant challenges. Key issues such as the imbalance in macrophage phenotype transition, delayed re-epithelialization, and excessive proliferation and differentiation of fibroblasts hinder wound healing and lead to fibrotic repair. To these, we developed an active shrinkage and antioxidative hydrogel with biomimetic mechanical functions (P&G@LMs) to reshape the healing microenvironment and effectively promote skin regeneration. The hydrogel's immediate hemostatic effect initiated sequential remodeling, the active shrinkage property sealed and contracted the wound at body temperature, and the antioxidative function eliminated ROS, promoting re-epithelialization. The spatiotemporal release of LMs (ACEI) during the inflammation phase regulated macrophage polarization towards the anti-inflammatory M2 phenotype, promoting progression to the proliferation phase. However, the profibrotic niche of macrophages induced a highly contractile α-SMA positive state in myofibroblasts, whereas the sustained LMs release could regulate this niche to control fibrosis and promote the correct biomechanical orientation of collagen. Notably, the biomimetic mechanics of the hydrogel mimicked the contraction characteristics of myofibroblasts, and the skin-like elastic modulus could accommodate the skin dynamic changes and restore the mechanical integrity of wound defect, partially substituting myofibroblasts' mechanical role in tissue repair. This study presents an innovative strategy for skin regeneration.

ROS-responsive injectable hydrogels loaded with exosomes carrying miR-4500 reverse liver fibrosis

The reversal of liver fibrosis requires effective strategies to reduce oxidative stress and inhibition of hepatic stellate cell (HSC) activation. MiR-4500 regulates pathological angiogenesis and collagen mRNA stability, with the potential to inhibit fibrosis. Herein, we explored the inhibition of HSC activation in vitro by exosomes (Exos) carrying miR-4500 and encapsulated ExosmiR-4500 in an intelligent injectable hydrogel with biological activity and reactive oxygen species (ROS) responsiveness for application in oxidative stress environments. Briefly, reversible boronic ester bonds were integrated into gelatin-based hydrogels through dynamic crosslinking of quaternized chitosan (QCS) and 4-carboxyphenylboronic acid (CPBA)-modified gelatin. The QCS-CPBA-Gelatin (QCG) hydrogel scavenged excess ROS from the local microenvironment and released ExosmiR-4500 through the dissociation of boronic ester bonds, providing a favorable microenvironment and in situ sustained-release drug delivery system for ExosmiR-4500. The results showed that QCG@ExosmiR-4500 hydrogel has biocompatibility, biodegradability, and slow-release ability, which could effectively clear ROS and inhibit HSC activation and pathological angiogenesis in vitro and in vivo. Furthermore, transcriptome analysis suggests that the pharmacological mechanism of the QCG@ExosmiR-4500 hydrogel is mainly related to anti-oxidation, anti-angiogenesis, anti-fibrosis processes, and signaling pathways. Thus, our study demonstrates that an intelligently responsive ExosmiR-4500 delivery system based on injectable hydrogels is a promising strategy for the treatment of liver fibrosis.

Electroactive Dressing with Selective Sorption of Exudate Enables Treatment of Complicated Wound

Exudate management and cell activity enhancement are vital to complicated wound healing. However, current exudate management dressings indiscriminately remove exudate, which is detrimental to cell activity enhancement. Herein, a novel class of electroactive bilayer (cMO/PVA) dressing is developed by constructing manganese oxide nanoneedle-clusters decorated commercial carbon cloth (MO), in situ casting polyvinyl alcohol (PVA) hydrogel, and finally charging. Benefitting from the hierarchical nanoneedle-cluster structure of MO, abundant active sites are sufficiently exposed to achieve high area-specific capacitances (e.g., 1881.3 mF cm-2), thereby establishing the long-lasting electric field for cMO/PVA dressing. Such a unique cMO/PVA dressing can realize extraordinary selective sorption toward noxious substances over nutrient substances during exudate management. Meanwhile, its long-term electrical stimulation therapy can promote cell proliferation and migration and enhance antibacterial property. As a result, our multifunctional cMO/PVA dressing can rapidly repair full-thickness wounds in type II diabetic rats, offering an advanced strategy for the treatment of complicated wounds.

Conductive hyaluronic acid/phytanic acid hydrogel to deliver recombinant human amelogenin for diabetic wound repair

Diabetic wounds present a considerable challenge in modern medicine due to their prolonged healing process, driven by sustained inflammation and impaired vascular regeneration. This study introduces a novel hydrogel network through osmosis, utilizing hyaluronic acid (HA) and phytic acid (PA) for their anti-inflammatory and antioxidant properties, respectively. By incorporating recombinant Human Amelogenin (rhAM), known for its angiogenic potential, we aimed to develop the HA-PA-rhAM hydrogel to enhance wound healing in diabetic rats. Our results indicate that this hydrogel has excellent mechanical properties, stability, electrical conductivity, and effective adaptation to irregular wound shapes. In vitro cellular assays demonstrated the hydrogel has an excellent biosafety profile, pro-cell migration, and pro-angiogenic capacity, and the diabetic rat full-thickness wound model further indicated the hydrogel's capacity to promote wound repair, by down-regulating inflammatory factors, promoting the transition of M1-type macrophages to M2-type, and up-regulating the expression of angiogenic markers. In summary, this functional hydrogel has a simple and efficient synthetic pathway and easy clinical translation, making it highly promising for treating chronic diabetic wounds.

Versatile conductive hydrogel orchestrating neuro-immune microenvironment for rapid diabetic wound healing through peripheral nerve regeneration

Diabetic wound (DW), notorious for prolonged healing processes due to the unregulated immune response, neuropathy, and persistent infection, poses a significant challenge to clinical management. Current strategies for treating DW primarily focus on alleviating the inflammatory milieu or promoting angiogenesis, while limited attention has been given to modulating the neuro-immune microenvironment. Thus, we present an electrically conductive hydrogel dressing and identify its neurogenesis influence in a nerve injury animal model initially by encouraging the proliferation and migration of Schwann cells. Further, endowed with the synergizing effect of near-infrared responsive release of curcumin and nature-inspired artificial heterogeneous melanin nanoparticles, it can harmonize the immune microenvironment by restoring the macrophage phenotype and scavenging excessive reactive oxygen species. This in-situ formed hydrogel also exhibits mild photothermal therapy antibacterial efficacy. In the infected DW model, this hydrogel effectively supports nerve regeneration and mitigates the immune microenvironment, thereby expediting the healing progress. The versatile hydrogel exhibits significant therapeutic potential for application in DW healing through fine-tuning the neuro-immune microenvironment.

Double Enzyme Active Hydrogel Program Regulates the Microenvironment of Staphylococcus aureus-Infected Pressure Ulcers

The treatment of infected pressure ulcers (IUPs) requires addressing diverse microenvironments. A pressing challenge is to effectively enhance the regenerative microenvironment at different stages of the healing process, tailoring interventions as needed. Here, a dual enzyme mimetic and bacterial responsive self-activating antimicrobial hydrogel designed to enhance IPUs healing is introduced. This hydrogel incorporates pH-responsive dual enzyme-active nanoplatforms (HNTs-Fe-Ag) encapsulated within a methacrylate-modified silk fibroin (SFMA) and dopamine methacrylamide (DMA) matrix. This composite hydrogel exhibits adaptive microenvironment regulation capabilities. Under the low pH microenvironment of bacterial infection, it has excellent antimicrobial activity by self-activating the •OH generation in conjunction with photothermal effects. Under the neutral and alkaline microenvironment of chronic inflammation, it catalyzes the decomposition of hydrogen peroxide (H2O2) to produce oxygen (O2), thereby alleviating hypoxia and scavenging reactive oxygen species (ROS), which in turn remodulates the phenotype of macrophages. The composite hydrogel demonstrates on-demand therapeutic effects in the microenvironment of infected wounds, significantly enhancing the regenerative microenvironment of IUPs by promoting wound closure, inflammation regulation, and collagen deposition through self-activated antimicrobial action during infection and adaptive hypoxia relief during recovery. This approach offers a novel strategy for developing smart wound dressings.

Polysaccharide-Based Self-Healing Hydrogel for pH-Induced Smart Release of Lauric Acid to Accelerate Wound Healing

It is highly desirable yet significantly challenging to fabricate an injectable, self-healing, controlled-release wound dressing that is responsive to the alkaline pH of the wounds. Herein, we propose a facile approach to prepare pH-responsive chitosan-oxidized carboxymethyl cellulose (CS-o-CMC) hydrogel constructs in which gelation was achieved via electrostatic and Schiff base formation. Importantly, the Schiff base was formed in acidic medium and the final pH of pregel solution was intrinsically raised to 7.0-7.4 due to the cross-linking by β-glycerol phosphate. The self-healing behavior of the hydrogel was an enthalpy-driven process and efficient in alkaline compared to acidic pH. The pH responsiveness offered a controlled release of lauric acid (LA) from CS-o-CMC/LA hydrogel and regulated the M2 polarization. Overall, reduction in inflammation led to rapid vascularization, reepithelialization, and significantly accelerated wound healing in rats. Our findings demonstrate a promising strategy for developing injectable, immunomodulatory wound dressings tailored to the challenging environment of wounds.

Nanoparticle-Reinforced Hydrogel with a Well-Defined Pore Structure for Sustainable Drug Release and Effective Wound Healing

Impaired chronic wounds are a common complication of diabetes. Inhibited angiogenesis and dysfunctional inflammation render diabetic wound healing a critical challenge. Herein, a sustainable therapeutic composite hydrogel is presented for diabetic wound healing, consisting of a cocktail formulation of anti-inflammatory and local anesthetic nanoparticles incorporated into a composite hydrogel. The surface-modified drug nanoparticles are loaded into the biocompatible hydrogels and cross-linked with a gel precursor to enhance the structure. The sustainable delivery system achieves more than 90% drug release, with a total therapy duration tunable from 4 to 72 h. Through the long-lasting anti-inflammatory and analgesic effects of the composite hydrogel, diabetic wounds are swiftly transitioned into the proliferation phase, augmenting the survival and migration of keratinocytes and facilitating neovascularization and collagen alignment in diabetic wounds. These effects significantly improve the wound healing rate and skin regeneration process, achieving a healing rate that is 17 times that of untreated wounds. This study demonstrates that the hydrogel platform loaded with cocktail drug nanoparticles is promising for the rapid healing of diabetic wounds.

Gum Arabic: A Commodity with Versatile Formulations and Applications

Gum Arabic (GA), or acacia gum, refers to the dried exudate produced by certain Acacia trees. GA is composed mainly of a mixture of polysaccharides and glycoproteins, with proportions that can slightly differ from one species to another. It is commonly utilized in the food and pharmaceutical industries as a stabilizer or an emulsifier owing to its biocompatibility, hydrophilicity, and antibacterial properties. In addition, GA can be manipulated as it possesses many functional groups that can be used in grafting, cross-linking, or chemical modifications to add a new feature to the developed material. In this review, we highlight recent GA-based formulations, including nanoparticles, hydrogels, nanofibers, membranes, or scaffolds, and their possible applications in tissue regeneration, cancer therapy, wound healing, biosensing, bioimaging, food packaging, and antimicrobial and antifouling membranes.

Enhanced hemostatic efficacy of cryogel with copper ion-loaded mesoporous bioactive glasses for acute and persistent bleeding

Uncontrolled acute and persistent bleeding, as well as with infection, is a great challenge because of the high mortality during treating the patients with injuries, complex surgery or bone marrow failure. Here, we develop an external form of natural components which is based on phosphorylated methacrylated gelatin (GelMA, G) cryogel (GP) loaded with tannic acid (TA)-mixed copper ion (Cu2+) mesoporous bioactive glasses (MBG), named after GP@MBG-Cu-TA cryogel, to address the goals of reduce persistent bleeding and enhance antibacterial activity. Structurally, GP@MBG-Cu-TA cryogel is based on GP, MBG loaded with TA and Cu2+ adheres to GP via hydrogen bonding. In vitro, GP@MBG-Cu-TA cryogel displays a good biocompatibility, hemostatic and antimicrobial capability. In vivo studies, GP@MBG-Cu-TA cryogel can enhance the hemostatic effect in the liver injury in SD rats for the acute bleeding, as well as in the aplastic anemia and hemophilia A mice with tail amputation for the persistent bleeding. In addition, GP@MBG-Cu-TA cryogel accelerates the skin wound repair in the mice with the bacterial contamination at the injury site. In sum, GP@MBG-Cu-TA cryogel is not only endowed with dual function of hemostatic and antimicrobial capability, but also can stop bleeding of the objects with either normal or abnormal coagulation function. Thus, GP@MBG-Cu-TA cryogel provides a promising candidate dressing for managing bleeding and bacterial complications in clinic.

Compliant immune response of silk-based biomaterials broadens application in wound treatment

The unique properties of sericin and silk fibroin (SF) favor their widespread application in biopharmaceuticals, particularly in wound treatment and bone repair. The immune response directly influences wound healing cycle, and the extensive immunomodulatory functions of silk-based nanoparticles and hydrogels have attracted wide attention. However, different silk-processing methods may trigger intense immune system resistance after implantation into the body. In this review, we elaborate on the inflammation and immune responses caused by the implantation of sericin and SF and also explore their anti-inflammatory properties and immune regulatory functions. More importantly, we describe the latest research progress in enhancing the immunotherapeutic and anti-inflammatory effects of composite materials prepared from silk from a mechanistic perspective. This review will provide a useful reference for using the correct processes to exploit silk-based biomaterials in different wound treatments.

Intelligent sequential degradation hydrogels by releasing bimetal-phenolic for enhanced diabetic wound healing

Healing of diabetic wounds is significantly impeded by a complex environment comprising biofilm formation, excessive inflammation, and compromised angiogenic capacity, leading to a disordered physiological healing process. Restoration and maintenance of a normal and orderly healing process in diabetic wounds remain unmet therapeutic objectives. Herein, an innovative bimetal-phenolic network hydrogel system is designed with a concentric circular structure, enabling dual-drug delivery with differentiated release kinetics. The outer layer, Cu@TA (tannic acid)-loaded ε-PL (poly-l-lysine)-SilMA (methacrylated silk), is engineered for an initial release to scavenge reactive oxygen species and exert antibacterial and anti-inflammatory effects. The inner layer, Zn@TA-loaded ε-PL-SilMA, is designed for sustained release to promote cell migration, modulate the immune microenvironment, and induce angiogenesis. By incorporating a polyphenolic-metal network, the Cu@TA/Zn@TA/ε-PL-SilMA hydrogel can alter its degradation rate, enabling the sequential release of Cu@TA and Zn@TA. An in vivo diabetic rat wound model, transcriptomic sequencing, and histological staining analyses revealed that the Cu@TA/Zn@TA/ε-PL-SilMA hydrogel effectively activates the Wnt/β-catenin signaling pathway, synergistically promoting wound healing by accelerating angiogenesis, effectively reducing inflammation, and promoting collagen deposition. This innovative hydrogel, with sequential degradation and release properties, is broadly applicable, ensures orderly wound healing, and holds promise for accelerating diabetic wound repair.

Glycyrrhizic acid and patchouli alcohol in Huoxiang Zhengqi attenuate intestinal inflammation and barrier injury via regulating endogenous corticosterone metabolism mediated by 11β-HSD1

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC), a chronic inflammatory bowel disease, has become a significant public health challenge due to the limited effectiveness of available therapies. Huoxiang Zhengqi (HXZQ), a well-established traditional Chinese formula, shows potential in managing UC, as suggested by clinical and pharmacological studies. However, the active components and mechanisms responsible for its effects remain unclear.

AIM OF STUDY

This study aimed to identify the bioactive components of HXZQ responsible for its therapeutic effects on UC and to elucidate their underlying mechanisms.

MATERIALS AND METHODS

The effect of HXZQ against dextran sodium sulfate (DSS)-induced colitis was investigated. Ingredients in HXZQ were characterized and analyzed in colitic mice using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). In vitro, biological activity of compounds was assessed using lipopolysaccharide (LPS)-induced Ana-1 cells and bone marrow-derived macrophages (BMDMs), tumor necrosis factor-alpha (TNF-α)-induced Caco-2 cells, and isolated intestinal crypts from colitic mice. These results were confirmed in vivo. The targets of the components were identified through bioinformatics analysis and validated via molecular docking, enzyme inhibition assays, and in vivo experiments. Hematoxylin and eosin (HE) staining, periodic acid-Schiff (PAS) staining, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative real-time polymerase chain reaction (qPCR) were employed to confirm the pharmaceutical effects.

RESULTS

A clinical equivalent dose of HXZQ (2.5 mL/kg) effectively treated DSS-induced colitis. A total of 113 compounds were identified in HXZQ, with 35 compounds detected in colitic mice. Glycyrrhizic acid (GA) and patchouli alcohol (PA) emerged as key contributors to the anti-colitic effects of HXZQ. Further investigation revealed that HXZQ and its active components decreased the levels of pro-inflammatory cytokines TNF-α, interleukin-1β (IL-1β), and interleukin-6 (IL-6) in colon, likely by inhibiting nuclear factor kappa-B (NF-κB) signaling pathway. This inhibition indirectly activated the intestinal farnesoid X receptor (FXR) signaling pathway, correcting bile acid imbalances caused by colitis. Additionally, these components significantly enhanced the expression of tight junction proteins ZO-1 and Occludin, as well as the adhesion protein E-cadherin, and reduced goblet cell loss, thereby repairing intestinal barrier injury. Mechanistically, GA and PA were found to inhibit 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) activity, leading to increased local active corticosterone levels in the intestine to exert anti-inflammatory effects. Notably, the inhibition of 11β-HSD1 with the selective inhibitor BVT2733 (BVT) ameliorated colitis in mice.

CONCLUSIONS

HXZQ exhibits therapeutic effects on UC, primarily through GA and PA inhibiting 11β-HSD1. This suggests new natural therapy approaches for UC and positions 11β-HSD1 as a potential target for colitis treatment.

Therapeutic Properties of M2 Macrophages in Chronic Wounds: An Innovative Area of Biomaterial-Assisted M2 Macrophage Targeted Therapy

Wound healing is a dynamic, multi-stage process essential for restoring skin integrity. Dysregulated wound healing is often linked to impaired macrophage function, particularly in individuals with chronic underlying conditions. Macrophages, as key regulators of wound healing, exhibit significant phenotypic diversity, ranging from the pro-healing M2 phenotype to the pro-inflammatory M1 phenotype. Imbalances in the M1/M2 ratio or hyperactivation of the M1 phenotype can delay the normal healing. Consequently, strategies aimed at suppressing the M1 phenotype or promoting the shift of local skin macrophages toward the M2 phenotype can potentially treat chronic non-healing wounds. This manuscript provides an overview of macrophages' role in normal and pathological wound-healing processes. It examines various therapeutic approaches targeting M2 macrophages, such as ex vivo-activated macrophage therapy, immunopharmacological strategies, and biomaterial-directed macrophage polarization. However, it also highlights that M2 macrophage therapies and immunopharmacological interventions may have drawbacks, including rapid phenotypic changes, adverse effects on other skin cells, biotoxicity, and concerns related to biocompatibility, stability, and drug degradation. Therefore, there is a need for more targeted macrophage-based therapies that ensure optimal biosafety, allowing for effective reprogramming of dysregulated macrophages and improved therapeutic outcomes. Recent advances in nano-biomaterials have demonstrated promising regenerative potential compared to traditional treatments. This review discusses the progress of biomaterial-assisted macrophage targeting in chronic wound repair and addresses the challenges faced in its clinical application. Additionally, it explores novel design concepts for combinational therapies, such as incorporating regenerative particles like exosomes into dressing materials or encapsulating them in microneedling systems to enhance wound healing rates.

Thermosensitive, injectable, antibacterial glabridin liposome/chitosan dual network hydrogel for diabetic wound healing

Thermosensitive hydrogels show great potential in healing diabetic wounds, but they are still challenged by the long healing time, risk of infectivity, and accumulation of melanin. Herein, a dual network hydrogel is designed, which consists of chlorogenic acid (CA) modified chitosan (CS) (CA@CS), poly(N-isopropylacrylamide) (PNIPAm), and glabridin liposomes (GL). The gelation transition temperature of the hydrogel is 32-34 °C, which thus endows it with superior injectability at ambient temperature. Moreover, GL/PNIPAm/CA@CS also exhibits excellent biocompatibility, and can promote the growth of epidermal cells, and the healing of diabetic wounds. GL/PNIPAm/CA@CS can also control the immune reactions by enhancing the release of CD206, and decreasing the formation of CD86 and ROS, which further promotes the production of CD31 and VEGF, and reduces the expression of pro-inflammatory factors, thus aiding in the healing of diabetic wounds. Furthermore, GL/PNIPAm/CA@CS can also suppress the growth bacterial, which can thus decrease the wound microbiota levels and facilitate the recovery of diabetic wounds. More importantly, it can reduce melanin production by 80 % due to the action of glabridin. Consequently, GL/PNIPAm/CA@CS shows significant promise in enhancing the wound healing in future and decreasing the accumulation of melanin.

Novel Silk Fibroin Based Bilayer Scaffolds for Bioabsorbable Internal Biliary Stenting

Biliary duct reconstruction is one of the most challenging parts of liver transplantation and accounts for 40%-60% of complications. While current stent-based devices on the market show promising results in reducing complications, they are manufactured from permanent synthetic materials and require a second reintervention for their removal. This exposes the patients to other potential complications and increases healthcare costs. This study develops a fabrication technique to produce a bioabsorbable biliary stent based on silk fibroin. The process used a dip-coating procedure for silk fibroin that produced highly smooth monolayer tubular specimens without the use of any additional surfactants during removal. This process was combined with an electrospinning step to produce bilayer structures through the deposition of electrospun silk fibroin on the outer surface. The structures proved to have promising mechanical, morphological, and cytocompatibility properties for use in the field of biliary stenting. Furthermore, the technique investigated proved to be reproducible, achieving an important requirement for large-scale use even in the presence of a biomaterial derived from a natural source. These results show the possibility of obtaining a completely bioabsorbable internal biliary stent that does not require any second reintervention. This study can be the starting point for further investigations both in vitro and in vivo to assess the suitability of silk fibroin biliary stents for clinical applications.

Adhesive and antibacterial guar gum-based nanocomposite hydrogel for remodeling wound healing microenvironment

Hydrogels are promising wound dressings due to their extracellular matrix-like properties and tunable structure-function characteristics. Besides the physical isolation effect, hydrogel dressings are highly expected to possess tissue-adhesive performance and antibacterial capacity, which are beneficial for their clinical translations. Herein, a guar gum (GG)-based nanocomposite hydrogel was fabricated by mixing methacrylated GG (GGMA), acrylic acid, acrylated 3-aminophenylboronic acid, mangiferin (MF)-loaded cetyltrimethyl ammonium chloride (CTAC) micelles (MF@CTAC) and radical initiator. This hydrogel exhibited stable and tunable mechanical property as well as excellent biocompatibility. Borate crosslinking and physical interactions of the hydrogel produced a certain degree of self-healing ability, good tissue adhesive and hemostatic capacity. MF endowed the hydrogel with good antioxidant ability and excellent synergistic antibacterial ability with CATC. In vivo experiments indicated that the hydrogel significantly accelerated wound healing with a narrower wound edge, thicker granulation tissue, maturer epidermis and dermis tissue, higher collagen deposition level, milder inflammatory response, and enhanced angiogenesis. The hydrogel without adding antibiotics and other exogenous active ingredients showed great application potential as a versatile wound dressing material.

Bailixiang tea, an herbal medicine formula, co-suppresses TLR2/MAPK8 and TLR2/NF-κB signaling pathways to protect against LPS-triggered cytokine storm in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has shown notable effectiveness and safety in managing illnesses linked to cytokine storm(CS). Bailixiang tea (BLX), an herbal medicine formula, which is a compound Chinese medicine composed of Thymus mongolicus (Ronniger) Ronniger (Bailixiang), Glycyrrhiza uralensis Fisch. (Gancao), Citrus reticulata Blanco (Chenpi), Cyperus rotundus L. (Xiangfu), and Perilla frutescens (L.) Britton (Zisu). The objective of this study was to explore the capacity of BLX in improving LPS-induced CS.

AIM OF THE STUDY

This study aimed to validate the mitigating effect of BLX on CS and to further investigate its mechanism.

MATERIALS AND METHODS

mice were orally administered BLX for 24 h after being treated with 5 mg/kg lipopolysaccharide (LPS). Histopathological observations further confirmed the significant protective effect of BLX treatment against LPS-induced lung and spleen damage. Additionally, we aimed to explore the molecular mechanism underlying its effects through blood proteomics and transcriptomics analyses. Real-Time Quantitative PCR (RT-qPCR) was utilized to detect the levels of Toll-like receptor 2 (TLR2), Matrix metalloproteinase 8 (MMP8), Matrix metalloproteinase 9 (MMP9), Integrin beta 2 (ITGB2), Mitogen-activated protein kinase 8 (MAPK8), Nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, epsilon (NFKBIE), Nuclear factor of kappa light polypeptide gene enhancer in B-cells 2 (NFKB2), and Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH)expressions in the lung tissue.

RESULTS

The results demonstrated that BLX effectively down-regulated the overproduction of interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) in both the serum and lung and spleen tissues. Furthermore, BLX effectively mitigated the overproduction of monocyte chemoattractant protein-1 (MCP-1) in the serum. Through comprehensive multi-omics analysis, it was revealed that BLX specifically targeted and regulated TLR2/MAPK8 and TLR2/NF-κB signaling pathways, which play a crucial role in the production of key cytokines.

CONCLUSIONS

The findings of this study demonstrate that Bailixiang tea possesses the ability to alleviate lung tissue damage and inhibit the development of LPS-induced cytokine storm in mice. These effects are attributed to the tea's ability to suppress the TLR2/MAPK8 and TLR2/NF-κB pathways. Consequently, this research highlights the potential application of Bailixiang tea as a treatment option for cytokine storm.

Bioinspired Adhesive Hydrogel Platform with Photothermal Antimicrobial, Antioxidant, and Angiogenic Properties for Whole-Process Management of Diabetic Wounds

Diabetic wound healing remains a major challenge in modern medicine. The persistent inflammation and immune dysfunction hinder angiogenesis by producing excessive ROS and increasing the susceptibility to bacterial infection. In this study, we developed an integrated strategy for whole-process management of diabetic wounds based on a bioinspired adhesive hydrogel platform with hemostasis, photothermal antimicrobial, antioxidant, anti-inflammatory, and angiogenic properties. A composite hydrogel (termed AQTGF) using poly(acrylic acid) (PAA) and quaternized chitosan (QCS) as the backbone materials and loaded with a TA-Gd/Fe-bimetallic-phenolic coordination polymer was prepared. The AQTGF hydrogel displayed favorable mechanical properties, self-healing capabilities, adhesion characteristics, and photothermal response performance. In vitro experiments demonstrated that the AQTGF hydrogel exhibits excellent photothermal antimicrobial capacity and antioxidant, angiogenic, and M2 macrophage phenotype polarizing properties. In addition, the rat tail amputation and liver hemostasis experiments demonstrated that the AQTGF hydrogel had excellent hemostasis performance. Moreover, in vivo studies have indicated that AQTGF hydrogel can facilitate diabetic wound healing by accelerating epidermal growth, promoting collagen deposition, modulating macrophage M2 polarization, inhibiting inflammation, and promoting angiogenesis. In conclusion, this study provides an adaptable hydrogel that holds promise for the treatment of chronic diabetic wounds.

Two-Component Hydrogels Built from Chinese Herbal Medicine-Derived Glycyrrhizic Acid and Puerarin: Assembly Mechanism, Self-Healing Properties, and Selective Antibacterial Activity

Chinese herbal medicine has offered a great treasure for discovering intrinsically bioactive low molecular weight gelators (LMWGs). Herein, the two-component hydrogels comprising glycyrrhizic acid (GA) and puerarin (PUE), the primary bioactive components, respectively, from herbs Glycyrrhiza uralensis Fisch and Pueraria lobata are successfully prepared. Combined spectroscopic characterizations reveal that hydrogen bonds are formed between GA and PUE molecules, which further drives the growth of nanofiber assemblies into gel networks. Importantly, micromorphological observation by scanning electron microscopy (SEM), synchrotron small-angle X-ray scattering (SAXS), and molecular dynamic simulation suggest that a coassembly pathway is involved in the gelling process. Such two-component hydrogels exhibit good injectable, self-healing, and adhesive properties. Interestingly, the mixed GA-PUE hydrogels demonstrate a more efficient and selective antibacterial activity toward S. aureus instead of E. coli, and a PUE ratio-dependent antibacterial activity toward S. aureus is also observed. Our work highlights that CHM-derived LMWGs can provide a scaffold for developing multicomponent hydrogels, which may afford novel and distinct properties compared with their individual ones. It is assumed that more multicomponent supramolecular hydrogels derived from CHM would appear to better address the challenges, particularly in the biomedical field.

Charge Regulation-Enhanced Type I Photosensitizer-Loaded Hydrogel Dressing for Hypoxic Bacterial Inhibition and Biofilm Elimination

Biofilm-induced chronic bacterial infections represent a significant challenge in modern medicine due to their resistance to conventional antibiotic treatments. Although photodynamic therapy (PDT) has emerged as a promising antibiotic-free antibacterial strategy, the hypoxic condition within biofilms and the lack of an effective local drug delivery system have limited the clinical effectiveness of photosensitizer (PS) agents. Herein, we propose a type of charge regulation-enhanced type I PS-loaded hydrogel dressing for treating biofilm infection. The charge regulation enables the multiple alkylation Nile blue (EB series) to exhibit substantially improved absorbance (∼2-fold), alkaline tolerance, and superoxide anion yield (2.2-4.2-fold) compared to the representative type I PS, sulfur-substituted Nile blue. Specifically, the enhanced electronic push-pull capabilities promote a more efficient electron recycling process, significantly boosting the efficiency of type I PDT. The superior PDT effect and enhanced bacterial uptake via charge regulation render the EB series more pronounced in hypoxic bacterial inhibition under red light or sunlight irradiation. Moreover, the hydrogel, constructed from oxidized dextran and quaternized chitosan, facilitates the localization and sustained retention of type I PSs, accelerating the healing of biofilm-infected wounds. This type I PS-based hydrogel could provide an efficient and user-friendly wound dressing for the clinical treatment and prevention of biofilm infections.

Glycyrrhizic Acid-Loaded Poloxamer and HPMC-Based In Situ Forming Gel of Acacia Honey for Improved Wound Dressing: Formulation Optimization and Characterization for Wound Treatment

The present study aims to formulate a stimuli-responsive in situ hydrogel system to codeliver acacia honey and glycyrrhizic acid for topical application that will aid in absorbing wound exudates, control microbial infestation, and produce angiogenic and antioxidant effects to accelerate wound healing. Therefore, both the natural active constituents were incorporated within an in situ hydrogel composed of poloxamer and hydroxypropyl methylcellulose (HPMC), where the concentrations of the polymers were optimized using Design-Expert software considering optimum values of the dependent variables, gelation temperature (34-37 °C), gelation time (<10 min), and the viscosity (2000-3500 cPs). The optimized formulation showed improved physicochemical properties such as mucoadhesiveness, porosity, swelling, and spreadability, which makes it suitable for wound application. Additionally, the in situ hydrogel exhibited potent in vitro and ex vivo antioxidant effects, in vitro antimicrobial activities, and ex ovo angiogenic effects. Furthermore, the optimized formulation was found to be nontoxic while tested in the HaCaT cell line and acute dermal irritation and corrosion study. The findings of the in vivo wound-healing studies in experimental animal models showed complete wound closure within 15 days of treatment and accelerated development of the extracellular matrix. In addition, the antioxidant, antimicrobial, angiogenic, and wound-healing properties of acacia honey and glycyrrhizic acid coloaded in situ hydrogel were also found to be promising when compared to the standard treatments. Overall, it can be concluded that the optimized stimuli-responsive in situ hydrogel containing two natural compounds could be an alternative to existing topical formulations for acute wounds.

Preparation of a chitosan/polyvinyl alcohol-based dual-network hydrogel for use as a potential wound-healing material for the sustainable release of drugs

Treating chronic wounds poses significant challenges in clinical medicine due to bacterial infection, reactive oxygen species (ROS) accumulation, and excessive inflammation. This study aimed to address these issues by developing a wound dressing with antibacterial, antioxidant, and anti-inflammatory properties. Chitosan was functionally modified with acrolein to covalently bind to epigallocatechin gallate (EGCG), enabling a high EGCG load. Subsequently, polyvinyl alcohol (PVA) and EGCG-modified chitosan were crosslinked to prepare a new double-network hydrogel with added cysteine (CSAEC/P50). CSAEC/P50 demonstrated optimal mechanical properties (low swelling rate, high water retention, and optimal flexibility), low hemolysis, high coagulation properties, and antibacterial and antioxidant activities. Cell scratch tests indicated that CSAEC/P50 can promote NIH3T3 cell migration. Immunofluorescence results showed that CSAEC/P50 promoted the transformation of proinflammatory M1 macrophages to anti-inflammatory M2 macrophages. These findings suggest that CSAEC/P50 has significant potential for use in wound dressing applications.

Role of macrophage polarization in diabetic foot ulcer healing: A bibliometric study

BACKGROUND

Diabetic foot ulcers (DFUs) are a significant contributor to disability and mortality in diabetic patients. Macrophage polarization and functional regulation are promising areas of research and show therapeutic potential in the field of DFU healing. However, the complex mechanism, the difficulty in clinical translation, and the large heterogeneity present significant challenges. Hence, this study was to comprehensively analyze the publication status and trends of studies on macrophage polarization and DFU healing.

AIM

To examine the relevant literature on macrophage polarization in DFU healing.

METHODS

A bibliometric analysis was conducted using the Web of Science database. Relevant literature was retrieved from the Web of Science Core Collection database between 2013 to 2023 using literature visualization and analysis software (VOSviewer and CiteSpace) and bibliometric online platforms. The obtained literature was then subjected to visualization and analysis of different countries/regions, institutions, journals, authors, and keywords to reveal the research's major trends and focus.

RESULTS

The number of publications on the role of macrophage polarization in DFU healing increased rapidly from 2013 to 2023, especially in the latter period. Chinese researchers were the most prolific in this field, with 217 publications, while American researchers had been engaged in this field for a longer period. Qian Tan of Nanjing Drum Tower Hospital and Qian Ding of Nanjing University were the first to publish in this field. Shanghai Jiao Tong University was the institution with the most publications (27). The keywords "bone marrow", "adjustment, replacement, response, tissue repair", and "activation, repair, differentiation" appeared more frequently. The study of macrophage polarization in DFU healing focused on the regulatory mechanism, gene expression, and other aspects.

CONCLUSION

This study through the bibliometric method reveals the research trends and development trends in this field of macrophage polarization in DFU healing from 2013 to 2023 in the Web of Science Core Collection database. The key hotspots in this field mainly include the regulation of macrophage activation, gene expression, wound tissue repair, and new wound materials. This study provides references for future research directions.

Zinc-induced photocrosslinked konjac glucomannan/glycyrrhizic acid hydrogel promotes skin wound healing in diabetic mice through immune regulation

Diabetic wound healing is a complex process. Owing to the lack of effective wound dressings, diabetic wound healing is often delayed. Here, injectable composite hydrogels with methacrylic anhydride (MA)-modified Konjac glucomannan and Zn2+-induced glycyrrhizic acid self-assembly were developed for skin wound healing in diabetic mice. Under induction with a photoinitiator and Zn2+, the hydrogel formed rapidly (<5 s) in vitro. The KGMMA/GA/Zn hydrogel demonstrated excellent mechanical properties (strain [40 %] >28 KPa) and physicochemical characteristics, which enabled the adaptation to various complex skin wound environments. Crucially, in vitro and in vivo experiments revealed that the hydrogel had good biocompatibility and low hemolytic properties (1.7 %) and promoted cell migration and tube formation. Hydrogels can modulate the innate properties of the immune system, regulate the polarization of macrophages in the M2 direction, and inhibit the production of ROS and inflammatory factors without the addition of cytokines or drugs in vivo and in vitro. In vivo animal experiments revealed that the hydrogel significantly accelerated the repair process of skin wounds, with a repair efficiency reaching 97.2 %. In summary, this novel hydrogel constitutes a highly effective wound healing dressing and may be a promising approach in tissue regeneration engineering.

Pluripotent polysaccharide coordinated hydrogels remodel inflammation, neovascularization and reepithelization for efficient diabetic wound prohealing

Chronic diabetic wounds seriously threaten the health and life of human beings, however, it is challenging to develop pluripotent dressings that comprehensively remodel inflammation microenvironment, neovascularization and reepithelization to achieve high performance healing in diabetic wounds. Herein we construct a bioinspired polysaccharide coordinated hydrogel composed of bisphosphate-modified β-glucan (BG) with bioactive metal ions of Zn2+ and Mg2+, in which multiple chelation enables fast gelation, self-healing, and dynamically sealing wounds. In vitro Mg2+ release from BGM or BGMZ could promote intracellular uptake of Zn2+ through upregulating Zn2+-related transporter protein ZIP6 while intracellular Mg2+ remained relatively stable via downregulating the Mg2+ transporter protein of MagT1. The screened lead hydrogel BGMZ could substantially polarize proinflammatory M1 to prohealing M2 phenotypes by the main BG-downregulating NF-kB signaling pathway, and both Mg2+ and Zn2+ release from BGMZ synergistically promoted proliferation and angiogenesis by upregulating PI3K/Akt signaling pathway, facilitating the reepithelization and tissue remodeling. Remarkably, single BGMZ treatment performed full-thickness wound closure, fast granulation and dermis regeneration, optimal neovascularization and reepithelization, high levels of overall collagen and fibrous collagen-I, and dense hair follicles, thus achieving high performance prohealing in diabetic wounds. Consequently, this study opens a new avenue to design pluripotent polysaccharide hydrogel dressing for structures and functions remodeling of chronic and diabetic wounds.

An injectable, self-healing, anti-infective, and anti-inflammatory novel glycyrrhizic acid hydrogel for promoting acute wound healing and regeneration

Introduction

Bacterial infection, a complex wound microenvironment, and a persistent inflammatory response in acute wounds can result in delayed healing and abnormal scar formation, thereby compromising the normal function and aesthetic appearance of skin tissue. This issue represents one of the most challenging problems in clinical practice. This study aims to develop a hydrogel dressing specifically designed for the treatment of acute wounds, providing immediate and effective protection for the affected areas. This innovation seeks to offer a novel and advanced solution for the management of acute wounds.

Methods

In this study, a composite hydrogel scaffold was synthesized through the reaction between oxidized glycyrrhizic acid and carboxymethyl chitosan Schiff base. The material properties of the hydrogel were systematically characterized, and its biocompatibility and antibacterial efficacy were rigorously evaluated. A rat wound model was established to compare multiple groups, thereby assessing the impact of the hydrogel on the wound microenvironment and wound repair.

Results

The results demonstrated that the OGA-CMCS hydrogel exhibited excellent injectability, biocompatibility, and antibacterial properties. It was capable of enhancing the wound microenvironment, which in turn influenced the polarization of macrophages from the M1 to the M2 phenotype, thereby mitigating the inflammatory response, promoting angiogenesis and granulation tissue regeneration, and accelerating wound healing.

Discussion

This study successfully developed a novel glycyrrhizin-based hydrogel dressing, which not only introduces innovative approaches for the emergency management of acute surface wound defects but also provides an experimental foundation. It is anticipated to contribute significantly to addressing relevant clinical challenges.

Ultrafast enzyme-responsive hydrogel for real-time assessment and treatment optimization in infected wounds

Monitoring wound infection and providing appropriate treatment are crucial for achieving favorable outcomes. However, the time-consuming nature of laboratory culture tests may delay timely intervention. To tackle this challenge, a simple yet effective HDG hydrogel, composed of hydrogen peroxide (H₂O₂), dopamine, and GelMA polymer, is developed for the ultrafast detection and treatment of Staphylococcus aureus (SA) infections. The HDG hydrogel detects SA by exploiting its secreted catalase to catalyze H₂O₂, producing oxygen, which in turn accelerates the polymerization of colorless dopamine into deep brown polydopamine (PDA). The bacterial detection process takes only 10 min with high sensitivity, and the results can be readily recognized by the naked eye or quantified using a cell phone-based digital analysis. Moreover, the HDG hydrogel provides a dual antibacterial mechanism through chemical and photothermal therapies via the generated PDA, significantly improving bacterial clearance. In animal experiments, the HDG hydrogel demonstrated promising capabilities in monitoring and eliminating bacteria, enhancing collagen deposition, reducing inflammation, and promoting the healing of infected wounds. This multifunctional design offers an enzyme-responsive strategy for the rapid assessment and management of infections, simplifying infection evaluation and facilitating the development of advanced wound dressings.

A functional hydrogel dressing based on glycyrrhizic acid with low-swelling and moisturizing properties for enhancing infected wound repair

Wound healing is a challenging due to the presence of bacterial infection, excessive inflammation and angiogenesis disorders. While traditional therapies struggle, a functional hydrogel can effectively repair wounds. However, the use of hydrogels is limited due to their high swelling and excessive dehydration characteristics. Herein, an interpenetrating polymer network hydrogel (HGP@EGCG) based on hyaluronic acid methacrylate (HAMA), glycyrrhizic acid (GA), polyvinyl alcohol (PVA), epigallocatechin-3-gallate (EGCG), and glycerin/water binary solvent was developed by self-assembly, physical entanglement and chemical crosslinking for infected wound healing. GA forms a primary network through self-assembly induced by Zn2+ and HAMA forms a more robust network structure through free radical polymerization as a rigid backbone, followed by the physical entanglement of PVA, which provides additional crosslinks within the network. The robust network structure conferred the HGP hydrogel with low swelling properties. HGP@EGCG hydrogels could adhere to the wound surface, exhibiting adequate tensile and compressive strength to withstand deformations induced by external forces. Then HGP@EGCG hydrogels with good moisture retention could facilitate the maintenance of wound hydration and prolong usage. Moreover, HGP@EGCG hydrogels could release the drug rapidly in an acidic environment and eliminate bacteria. The designed hydrogels demonstrated multifaceted functionality, including suitable adhesion, low swelling, good moisture retention, and efficient antibacterial properties. Both in vitro and in vivo investigations confirmed that HGP@EGCG hydrogels had good biocompatibility and promoted human umbilical vein endothelial cell migration and tube formation, which markedly expedited wound healing. Consequently, HGP@EGCG hydrogels present a broad spectrum of potential applications in the clinical treatment of infected wounds.

Intrinsic immunomodulatory hydrogels for chronic inflammation

The immune system plays a pivotal role in maintaining physiological homeostasis and influencing disease processes. Dysregulated immune responses drive chronic inflammation, which in turn results in a range of diseases that are among the leading causes of death globally. Traditional immune interventions, which aim to regulate either insufficient or excessive inflammation, frequently entail lifelong comorbidities and the risk of severe side effects. In this context, intrinsic immunomodulatory hydrogels, designed to precisely control the local immune microenvironment, have recently attracted increasing attention. In particular, these advanced hydrogels not only function as delivery mechanisms but also actively engage in immune modulation, optimizing interactions with the immune system for enhanced tissue repair, thereby providing a sophisticated strategy for managing chronic inflammation. In this tutorial review, we outline key elements of chronic inflammation and subsequently explore the strategic design principles of intrinsic immunomodulatory hydrogels based on these elements. Finally, we examine the challenges and prospects of such immunomodulatory hydrogels, which are expected to inspire further preclinical research and clinical translation in addressing chronic inflammation.

Multifunctional Adhesive Hydrogels: From Design to Biomedical Applications

Adhesive hydrogels characterized by structural properties similar to the extracellular matrix, excellent biocompatibility, controlled degradation, and tunable mechanical properties have demonstrated significant potential in biomedical applications, including tissue engineering, biosensors, and drug delivery systems. These hydrogels exhibit remarkable adhesion to target substrates and can be rationally engineered to meet specific requirements. In recent decades, adhesive hydrogels have experienced significant advancements driven by the introduction of numerous multifunctional design strategies. This review initially summarizes the chemical bond-based design strategies for tissue adhesion, encompassing static covalent bonds, dynamic covalent bonds, and non-covalent interactions. Subsequently, the multiple functionalities imparted by these diverse design strategies, including highly stretchable and tough performances, responsiveness to microenvironments, anti-freezing/heating properties, conductivity, antibacterial activity, and hemostatic properties are discussed. In addition, recent advances in the biomedical applications of adhesive hydrogels, focusing on tissue repair, drug delivery, medical devices, and wearable sensors are reviewed. Finally, the current challenges are highlighted and future trends in this rapidly evolving field are discussed.

Dynamic Hyaluronic Acid Hydrogels for Comprehensively Regulating Inflammation, Angiogenesis, and Metabolism to Effectively Proheal Diabetic Wounds

Despite the great progress of various multifunctional wound dressings, it is challenging to simultaneously achieve complete healing and functional remodeling for diabetic foot ulcers and refractory chronic wounds. Aiming to comprehensively regulate chronic inflammation, angiogenesis, and metabolism processes, herein, a novel kind of dynamic hyaluronic acid (HA) hydrogel was designed by combining boronate and coordination chemistry. Besides having injectability, self-healing, and detachment properties, dynamic HA hydrogels presented diabetic wound-responsive degradation and controllable H2S release. They could efficiently polarize M1-to-M2 polarization and regulate inflammatory cytokine secretion and multiple inflammation-related mRNA expressions through cooperative actions of reactive oxygen species elimination + H2S release + Zn2+ regulation, thus driving chronic inflammation into the proliferation and remodeling stages. Moreover, the screened lead hydrogel HTZS could regulate angiogenesis-related signaling pathways and metabolism processes to promote neovascularization and mature vessel formation, re-epithelization, high-level collagen-I deposition, and dense hair follicle regeneration, achieving complete healing and functional remodeling in diabetic wounds. Importantly, this work opens a new avenue to design dynamic biopolymer hydrogels for high-performance wound dressing and decipher the key role of multiple orchestrated regulations of inflammation-angiogenesis-metabolism on complete healing and functional remodeling in chronic and diabetic wounds.

Progress in the Application of Multifunctional Composite Hydrogels in Promoting Tissue Repair

Tissue repair is an extremely complex process, and effectively promoting tissue regeneration remains a significant clinical challenge. Hydrogel materials, which exhibit physical properties closely resembling those of living tissues, including high water content, oxygen permeability, and softness, have the potential to revolutionize the field of tissue repair. However, the presence of various complex conditions, such as infection, ischemia, and hypoxia in tissue defects, means that hydrogels with simple structures and functions are often insufficient to meet the diverse needs of tissue repair. Researchers have focused on integrating multiple drugs, nanomaterials, bioactive substances, and stem cells into hydrogel matrices to develop novel multifunctional composite hydrogels for addressing these challenges, which have superior antibacterial properties, hemostatic abilities, self-healing capacities, and excellent mechanical properties. These composite hydrogels are designed to enhance tissue repair and have become an important direction in the current research. This review provides a comprehensive review of the recent advances in the application of multifunctional composite hydrogels in promoting tissue repair, including drug-loaded hydrogels, nanomaterial composite hydrogels, bioactive substance composite hydrogels, and stem cell composite hydrogels.

Tools for regulating metabolic diseases: extracellular vesicles from adipose macrophages

Metabolic diseases have gradually become one of the most significant global medical burdens. Diseases such as obesity, diabetes, and metabolic syndrome, along with their complications, are clinically categorized as metabolic diseases. Long-term oral medication significantly reduces patient compliance and quality of life. Therefore, alternative therapies that intervene at the cellular level or target the root causes of metabolic diseases might help change this predicament. Research has found that extracellular vesicles derived from adipose macrophages can effectively regulate metabolic diseases by influencing the disease's development. This regulation is likely related to the role of these extracellular vesicles as important mediators in modulating adipose tissue function and insulin sensitivity, and their involvement in the crosstalk between adipocytes and macrophages. This review aims to describe the regulation of metabolic diseases mediated by adipose macrophage-derived extracellular vesicles, with a focus on their involvement in adipocyte crosstalk, the regulation of metabolism-related autoimmunity, and their potential as therapeutic agents for metabolic diseases, providing new avenues for diagnosis and treatment.

MCC950 promotes diabetic wound healing through modulating macrophage polarization in an MDSC-dependent manner

Diabetic foot ulcers (DFUs) are serious skin injuries whereby the wound healing process is frequently stalled in the inflammatory phase. Currently, there is a lack of effective therapeutic strategies. MCC950, a highly selective nod-like receptor family pyrin domain containing 3 (NLRP3) inhibitor, has been reported to show strong anti-inflammation effects in many diseases. In this study, we unveiled the role of MCC950 in DFU mice model and its underlying molecular mechanisms. MCC950 could significantly accelerate diabetic wound healing, as shown by shortened healing time and better healing quality. Moreover, increased M2 phenotype macrophages and decreased pro-inflammatory genes were observed in MCC950-treated DFU mice. Additionally, myeloid-derived suppressor cells (MDSCs) were significantly increased in blood, spleen and wound tissues at different time courses. Specifically, MCC950 could recruit more MDSCs in an early phase in DFU mice, exerting an anti-inflammation effect. We identified the cell crosstalk between macrophages and MDSCs with MCC950 treatment process. Depleting MDSCs in vivo could eliminate the therapeutic effect of MCC950 on diabetic wound healing through inhibiting M2 macrophage polarization. Besides, MDSCs isolated from the wounds of MCC950 or saline treated mice were cocultured with bone marrow derived macrophage (BMDM) in a transwell system. Results confirmed that MDSCs sorted from MCC950 treated mice caused a significant increased percentage of M2 macrophages. Collectively, our findings suggest that the administration of MCC950 has the potential to accelerate diabetic wound healing by promoting M2 macrophage polarization in an MDSC-dependent manner. This study provides valuable insights into the utilization of pharmacological agents for DFU treatment.

Amorphous zinc phosphate nanoclusters loaded polycarbonate thermosensitive hydrogel: An innovative strategy for promoting wound healing

Skin trauma is a matter of great concern for public health, emphasizing the importance of reconstructing the microenvironment at the trauma site to facilitate tissue regeneration. Therefore, the investigation of innovative wound dressings has significant research and clinical implications. In this study, we prepared a thermosensitive hydrogel based on a hydrophilic-hydrophobic-hydrophilic triblock polycarbonate polymer (PTP), and created a composite hydrogel, PTPH-AZP, by incorporating amorphous zinc phosphate (AZP) nanoclusters. We evaluated the effects of PTPH-AZP on human umbilical vein endothelial cells (HUVECs) and the ability to promote skin wound healing. According to the results, PTPH-AZP was found to promote the proliferation, migration, and tube formation of HUVECs through the sustained release of Zn2+ at appropriate concentrations. In vivo experiments demonstrated that in the early-mid stages of wound healing, PTPH-AZP promotes increases in Platelet Endothelial Cell Adhesion Molecule-1 (CD31) and α-Smooth Muscle Actin (α-SMA) content within the wound area, facilitating accelerated re-epithelialization and enhanced collagen deposition. In later healing stages, epidermal thickness in the PTPH-AZP treated group was significantly improved, aligning with surrounding intact skin with no instances of attenuated or hypertrophic scarring observed. The findings from the in vivo study suggested that PTPH-AZP may have a positive impact on vascularization and wound healing. In conclusion, this study presents a promising strategy for skin wound healing, highlighting the potential of PTPH-AZP as an effective therapeutic approach.

Immunomodulatory Hydrogel for Electrostatically Capturing Pro-inflammatory Factors and Chemically Scavenging Reactive Oxygen Species in Chronic Diabetic Wound Remodeling

Diabetic wound exhibits the complex characteristics involving continuous oxidative stress and excessive expression of pro-inflammatory cytokines to cause a long-term inflammatory microenvironment. The repair healing of chronic diabetic wounding is tremendously hindered due to persistent inflammatory reaction. To address the aforementioned issues, here, a dual-functional hydrogel is designed, consisting of N1-(4-boronobenzyl)-N3-(4-boronophenyl)-N1, N1, N3, N3-tetramethylpropane-1, 3-diaminium (TSPBA) modified polyvinyl alcohol (PVA) and methacrylamide carboxymethyl chitosan (CMCSMA) can not only electrostatically adsorb proinflammatory cytokines of IL1-β and TNF-α, but can also chemically scavenge the excessive reactive oxygen species (ROS) in situ. Both in vitro and in vivo evaluations verify that the negatively charged and ROS-responsive hydrogel (NCRH) can effectively modulate the chronic inflammatory microenvironment of diabetic wounds and significantly enhance wound remodeling. More importantly, the well-designed NCRH shows a superior skin recovery in comparison with the commercial competitor product of wound dressing. Consequently, the current work highlights the need for new strategies to expedite the healing process of diabetic wounds and offers a wound dressing material with immunomodulation.

Dissolvable microneedle-based wound dressing transdermally and continuously delivers anti-inflammatory and pro-angiogenic exosomes for diabetic wound treatment

Due to overactive inflammation and hindered angiogenesis, self-healing of diabetic wounds (DW) remains challenging in the clinic. Platelet-derived exosomes (PLT-Exos), a novel exosome capable of anti-inflammation and pro-angiogenesis, show great potential in DW treatment. However, previous administration of exosomes into skin wounds is topical daub or intradermal injection, which cannot intradermally deliver PLT-Exos into the dermis layer, thus impeding its long-term efficacy in anti-inflammation and pro-angiogenesis. Herein, a dissolvable microneedle-based wound dressing (PLT-Exos@ADMMA-MN) was developed for transdermal and long-term delivery of PLT-Exos. Firstly, a photo-crosslinking methacrylated acellular dermal matrix-based hydrogel (ADMMA-GEL), showing physiochemical tailorability, fast-gelling performance, excellent biocompatibility, and pro-angiogenic capacities, was synthesized as a base material of our dressing. For endowing the dressing with anti-inflammation and pro-angiogenesis, PLT-Exos were encapsulated into ADMMA-GEL with a minimum effective concentration determined by our in-vitro experiments. Then, in-vitro results show that this dressing exhibits excellent properties in anti-inflammation and pro-angiogenesis. Lastly, in-vivo experiments showed that this dressing could continuously and transdermally deliver PLT-Exos into skin wounds to switch local macrophage into M2 phenotype while stimulating neovascularization, thus proving a low-inflammatory and pro-angiogenic microenvironment for DW healing. Collectively, this study provides a novel wound dressing capable of suppressing inflammation and stimulating vascularization for DW treatment.

Copper(II) aromatic heterocyclic complexes of Gatifloxacin with multi-targeting capabilities for antibacterial therapy and combating antibiotic resistance

In recent years, the pace of novel antibiotic development has been relatively slow, intensifying the urgency of the antibiotic resistance issue. Consequently, scientists have turned their attention to enhancing antibiotic activity by coordinating antibiotics with metal elements. This study designs and synthesizes three novel antibacterial copper complexes based on Gatifloxacin. These complexes exhibit potent antibacterial activity, notably Cu-1, with a minimum inhibitory concentration (MIC) of only 0.063 μg/mL against Staphylococcus aureus (S.aureus), demonstrating potent bacteriostatic capabilities. Further investigations unveil the antibacterial mechanisms of complex Cu-1, revealing its ability not only to suppress the activities of DNA gyrase and topoisomerases IV, but also to effectively inhibit biofilm formation and disrupt the integrity of cell membrane. This multi-targeting action contributes to mitigating the risk of bacterial resistance emergence. Additionally, synergy between Cu-1 and conventional antibiotics is confirmed through checkerboard assays, offering novel strategies for antibacterial therapy. In vivo experiments using a murine model of S.aureus infection demonstrate the significant antibacterial efficacy of Cu-1, providing robust support for its potential in treating S.aureus infections. This study demonstrates that the coordination complexes formed by copper, Gatifloxacin and suitable aromatic heterocyclic ligands exhibit multi-targeting characteristics against bacteria, offering a new direction for combating antibiotic resistance in antibacterial therapy.

Glycyrrhizic acid-based multifunctional nanoplatform for tumor microenvironment regulation

Natural compounds demonstrate unique therapeutic advantages for cancer treatment, primarily through direct tumor suppression or interference with the tumor microenvironment (TME). Glycyrrhizic acid (GL), a bioactive ingredient derived from the medicinal herb Glycyrrhiza uralensis Fisch., and its sapogenin glycyrrhetinic acid (GA), have been recognized for their ability to inhibit angiogenesis and remodel the TME. Consequently, the combination of GL with other therapeutic agents offers superior therapeutic benefits. Given GL's amphiphilic structure, self-assembly capability, and liver cancer targeting capacity, various GL-based nanoscale drug delivery systems have been developed. These GL-based nanosystems exhibit angiogenesis suppression and TME regulation properties, synergistically enhancing anti-cancer effects. This review summarizes recent advances in GL-based nanosystems, including polymer-drug micelles, drug-drug assembly nanoparticles (NPs), liposomes, and nanogels, for cancer treatment and tumor postoperative care, providing new insights into the anti-cancer potential of natural compounds. Additionally, the review discusses existing challenges and future perspectives for translating GL-based nanosystems from bench to bedside.