Thou shall not heal: Overcoming the non-healing behaviour of diabetic foot ulcers by engineering the inflammatory microenvironment

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

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

A novel hydrogel loaded with plant exosomes and stem cell exosomes as a new strategy for treating diabetic wounds

Diabetic wound healing is constrained by various factors, including chronic inflammation, sustained oxidative stress, impaired angiogenesis, and abnormal wound microenvironments. Exosomes derived from mesenchymal stem cells (MSC-exo) contain a wealth of bioactive substances that play a positive role in promoting diabetic wound healing. Plant-derived exosomes, as a novel therapeutic approach, are continuously being explored. Momordica charantia (MC) has been shown to possess blood glucose-lowering effects, and its exosomes are of significant relevance for treating diabetic wounds. However, direct application of exosomes to wounds faces challenges such as poor stability and short retention time, limiting their therapeutic effectiveness and clinical applicability. Encapsulating exosomes in hydrogels is an effective strategy to preserve their bioactivity. In this study, we fabricated a hydrogel loaded with MSC-exo and MC exosomes (MC-exo) by photopolymerization of methacrylated gelatin (GelMA) and dopamine (MEMC-Gel). The resulting MEMC-Gel exhibited favorable mechanical properties, adhesion, degradability, absorbency, and biocompatibility. In vitro, MEMC-Gel demonstrated the ability to resist inflammation, counter oxidative stress, promote fibroblast migration, support endothelial cell angiogenesis, and regulate macrophage polarization. In a diabetic mouse wound model, MEMC-Gel accelerated wound healing by inhibiting inflammation and oxidative stress, modulating macrophage immune responses and hyperglycemia within the microenvironment, promoting angiogenesis, and enhancing epithelialization. In conclusion, MEMC-Gel is an outstanding hydrogel dressing that synergistically promotes repair by loading MSC-exo and MC-exo, significantly accelerating diabetic wound healing through multiple mechanisms. This multifunctional hydrogel, based on exosomes from two different sources, provides an innovative therapeutic strategy for diabetic wound repair with broad clinical application potential.

Local delivery of siRNA using lipid-based nanocarriers with ROS-scavenging ability for accelerated chronic wound healing in diabetes

Diabetic wound healing poses a significant clinical challenge with limited therapeutic efficacy due to uncontrolled reactive oxygen species (ROS), inflammatory responses, and extracellular matrix (ECM) degradation caused by abnormal macrophage activity in the wound microenvironment. To address these concerns, we propose a novel formulation that combines Tempo-conjugated lipid with the commercially cationic lipid DOTAP to expedite diabetic wound healing through targeted siRNA delivery (cLpT@siRNA) and restoration of the wound microenvironment. The developed cLpT@siRNA nanocomplexes effectively scavenge excessive ROS levels, facilitate polarization of proinflammatory M1 macrophages towards an anti-inflammatory M2 phenotype, and suppress MMP9 gene expression in macrophages. In the ICR mouse model of diabetic wounds, cLpT@siRNA nanocomplexes significantly accelerate wound healing, promoting neovascularization and collagen deposition. Overall, the cLpT@siRNA nanocomplexes based on antioxidant and cationic lipids provide a promising strategy for delivering siRNA in diabetic wound treatment and hold great potential for clinical translation.

Recent advances in structural and functional design of electrospun nanofibers for wound healing

The global prevalence of acute and chronic wounds has surged, escalating healthcare burdens and necessitating advanced therapeutic strategies for effective wound management. Electrospun nanofibers have emerged as promising biomimetic platforms for tissue engineering and drug delivery, due to their structural resemblance to the native extracellular matrix (ECM), high porosity, and tunable surface-to-volume ratio. Recent advances in structural design have expanded their applications from conventional two-dimensional (2D) wound dressings to multifunctional three-dimensional (3D) architectures, enabling enhanced mechanical adaptability, bioactive molecule loading, and spatiotemporal control over wound microenvironments. These innovations leverage nanofibers' customizable topography and composition to recapitulate critical ECM cues, thereby fostering cell proliferation, angiogenesis, and immunomodulation during tissue regeneration. This review systematically evaluates cutting-edge strategies focusing on optimizing 2D arrangements and the structural design of multilayered and functionally patterned 3D electrospun nanofibers in wound healing applications. We further present the advantages and limitations of various nanofiber structures, along with the key challenges and future directions for advancing electrospun nanofibers specifically designed for enhanced wound healing.

Development of a bioactive hyaluronic acid hydrogel functionalised with antimicrobial peptides for the treatment of chronic wounds

Chronic wounds present significant clinical challenges due to delayed healing and high infection risk. This study presents the development and characterisation of acrylated hyaluronic acid (AcHyA) hydrogels functionalised with gelatin (G) and the antimicrobial peptide (AMP) PP4-3.1 to enhance cellular responses while providing antimicrobial activity. AcHyA-G and AcHyA-AMP hydrogels were formed via thiol-acrylate crosslinking, enabling in situ AcHyA hydrogel formation with stable mechanical properties across varying gelatin concentrations. Biophysical characterisation of AcHyA-G hydrogels showed rapid gelation, elastic behaviour, uniform mesh size, and consistent molecular diffusion across all formulations. Moreover, the presence of gelatin enhanced stability without affecting the hydrogel's degradation kinetics. AcHyA-G hydrogels supported the adhesion and spreading of key cell types involved in wound repair (dermal fibroblasts and endothelial cells), with 0.5% gelatin identified as the optimal effective concentration. Furthermore, the conjugation of the AMP conferred bactericidal activity against Staphylococcus aureus and Escherichia coli, two of the most prevalent bacterial species found in chronically infected wounds. These results highlight the dual function of AcHyA-AMP hydrogels in promoting cellular responses and antimicrobial activity, offering a promising strategy for chronic wound treatment. Further in vivo studies are needed to evaluate their efficacy, including in diabetic foot ulcers.

Defect-Rich MoO3-X@CuO2 Nanosheets Mediated Ultrasound-Enhanced Cuproptosis Antibacterial Activity and M2 Macrophage Reprogramming for Optimizing Diabetic Wound Repairment

Diabetic wounds are often plagued by persistent bacterial infections, which exacerbate inflammation and impair healing processes such as collagen deposition and fibroblast migration. Conventional antibiotic therapies frequently prove ineffective and can even hinder wound repair. To address these challenges, biodegradable MoO3-x@CuO2 ion disruptors (MCO IDs) that for comprehensive diabetic wound treatment is developed. The MCO IDs generate a burst of multimodal reactive oxygen species (ROS) that effectively penetrate bacterial defenses and disrupt redox homeostasis. Released copper ions induce proteotoxic stress-like bacterial death by targeting lipoylated and iron-sulfur cluster proteins. Transcriptomic and metabolomic analyses reveal that this mechanism systematically inhibits bacterial energy metabolism and gene expression, effectively suppressing proliferation. Following bacterial eradication, the released copper ions promote macrophage repolarization to the M2 phenotype, mitigating chronic inflammation and stimulating wound healing. Furthermore, to enhance wound management, a portable wound dressing (PVA-MCO) is fabricated by electrospinning polyvinyl alcohol (PVA) incorporating the MCO IDs. In vivo studies demonstrate that the PVA-MCO dressing effectively eliminates pathogenic bacteria and promotes collagen deposition, angiogenesis, and epithelialization, thereby accelerating diabetic wound healing. This multifaceted therapeutic strategy offers a promising solution for managing persistent infections and promoting diabetic wound repair.

Electro- and Magneto-Active Biomaterials for Diabetic Tissue Repair: Advantages and Applications

The diabetic tissue repair process is frequently hindered by persistent inflammation, infection risks, and a compromised tissue microenvironment, which lead to delayed wound healing and significantly impact the quality of life for diabetic patients. Electromagnetic biomaterials offer a promising solution by enabling the intelligent detection of diabetic wounds through electric and magnetic effects, while simultaneously improving the pathological microenvironment by reducing oxidative stress, modulating immune responses, and exhibiting antibacterial action. Additionally, these materials inherently promote tissue regeneration by regulating cellular behavior and facilitating vascular and neural repair. Compared to traditional biomaterials, electromagnetic biomaterials provide advantages such as noninvasiveness, deep tissue penetration, intelligent responsiveness, and multi-stimuli synergy, demonstrating significant potential to overcome the challenges of diabetic tissue repair. This review comprehensively examines the superiority of electromagnetic biomaterials in diabetic tissue repair, elucidates the underlying biological mechanisms, and discusses specific design strategies and applications tailored to the pathological characteristics of diabetic wounds, with a focus on skin wound healing and bone defect repair. By addressing current limitations and pursuing multi-faceted strategies, electromagnetic biomaterials hold significant potential to improve clinical outcomes and enhance the quality of life for diabetic patients.

Recent advances in hyaluronic acid-based hydrogels for diabetic wound healing

Diabetic wound healing represents a complex biological challenge, often impeded by disrupted cellular processes and dysregulated inflammation, which can lead to chronic and non-healing wounds. Given the significant burden on patients and the healthcare system, there is an urgent need for advanced therapeutic strategies. Hyaluronic acid (HA)-based hydrogels have emerged as a promising solution due to their biocompatibility, biodegradability, and unique physiological functions. This review aims to provide a comprehensive overview of recent advances in HA-based hydrogels, highlighting their potential in addressing diabetic wound complications. Specifically, it examines challenges such as hyperglycemia-induced oxidative stress and impaired cellular signaling within the intricate diabetic wound microenvironment. Moreover, the review explores the composition and properties of HA, including its adhesive capabilities and role in reducing surgical trauma. Various crosslinking strategies and functional modifications are also discussed to endow HA-based hydrogels with antioxidant, antimicrobial, and growth factor-releasing capabilities. By summarizing the latest research and identifying areas for further exploration, this review contributes to the development of more effective HA-based hydrogel formulations for diabetic wound healing.

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

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

RNA N6-methyladenosine demethylase FTO promotes diabetic wound healing through TRIB3-mediated autophagy in an m6A-YTHDF2-dependent manner

N6-methyladenosine (m6A) RNA modification impaired autophagy results in delayed diabetic wound healing. In this study, it was found that fat mass and obesity-associated protein (FTO) was significantly downregulated in the epidermis of diabetic patients, STZ-induced mice and db/db mice (type I and II diabetic mice) with prolonged hyperglycemia, as well as in different types of keratinocyte cell lines treated with short-term high glucose medium. The knockout of FTO affected the biological functions of keratinocytes, including enhanced apoptosis, inhibited autophagy, and delayed wound healing, producing consistent results with high-glucose medium treatment. High-throughput analysis revealed that tribbles pseudokinase 3 (TRIB3) served as the downstream target gene of FTO. In addition, both in vitro and in vivo experiments, TRIB3 overexpression partially rescued biological functions caused by FTO-depletion, promoting keratinocyte migration and proliferation via autophagy. Epigenetically, FTO modulated m6A modification in the 3'UTR of TRIB3 mRNA and enhanced TRIB3 stability in a YTHDF2-dependent manner. Collectively, this study identifies FTO as an accelerator of diabetic wound healing and modulates autophagy via regulating TRIB3 in keratinocytes, thereby benefiting the development of a m6A-targeted therapy for refractory diabetic wounds.

Spatiotemporal single-cell roadmap of human skin wound healing

Wound healing is vital for human health, yet the details of cellular dynamics and coordination in human wound repair remain largely unexplored. To address this, we conducted single-cell multi-omics analyses on human skin wound tissues through inflammation, proliferation, and remodeling phases of wound repair from the same individuals, monitoring the cellular and molecular dynamics of human skin wound healing at an unprecedented spatiotemporal resolution. This singular roadmap reveals the cellular architecture of the wound margin and identifies FOSL1 as a critical driver of re-epithelialization. It shows that pro-inflammatory macrophages and fibroblasts sequentially support keratinocyte migration like a relay race across different healing stages. Comparison with single-cell data from venous and diabetic foot ulcers uncovers a link between failed keratinocyte migration and impaired inflammatory response in chronic wounds. Additionally, comparing human and mouse acute wound transcriptomes underscores the indispensable value of this roadmap in bridging basic research with clinical innovations.

Self-Cascade of ROS/Glucose-Scavenging Immunomodulatory Hydrogels for Programmed Therapeutics of Infected Diabetic Ulcers via Nrf2/NF-κB Pathway

Diabetic ulcers (DUs) are characterized by a microenvironment with high oxidative stress, high blood glucose levels, and recalcitrant bacterial infections. This microenvironment is accompanied by long-term suppression of endogenous antioxidant systems, which makes their clinical management extremely challenging. To address this issue, a hybridized novel gold-palladium (AuPd) nanoshell of the injectable/injectable hydrogel system UiO/AuPdshells/BNN6/PEG@Gel (UAPsBP@Gel) is developed. The system is capable of acting as a nitric oxide (NO) reactor utilizing synergistic therapy that harnesses NIR-II light-triggered photothermal effects and controlled release of NO gas for synergistic treatment to eradicate biofilm infections at different depths. The AuPd nanoshells exhibits superoxide dismutase (SOD)-, glucose oxidase (GOx)-, and catalase (CAT)-like activities, enabling self-cascade process for scavenging both reactive oxygen species (ROS) and glucose. This activity reshapes the DUs microenvironment, switches on the endogenous antioxidant Nrf2/HO-1 pathway and inhibits the NF-κB pathway, promotes macrophage polarization toward the anti-inflammatory M2 phenotype, and reduces oxidative stress, resulting in efficient immunomodulation. In vitro/in vivo results demonstrate that the UAPsBP@Gel can multifacetedly enhance the epithelial rejuvenation process through wound hemostasis, pro-cellular migration and vascularization. These results highlight that a programmed therapeutic based on UBAPsP@Gel tailored to the different stages of infected DUs can meet complex clinical needs.

Glucose-fueled cationic nanomotors for promoting the healing of infected diabetic wounds

Hyperglycemia-promoted bacterial infection will seriously exacerbate diabetic wounds, and its current clinical treatments are suffering from the adverse effects associated with off-target, bacterial resistance, and glycemic fluctuation. Herein, we present a kind of glucose-fueled cationic nanomotors capable of remarkably enhancing antibacterial efficacy, and thus expediting diabetic wound healing. The nanomotors have positively charged surfaces, and consist of mesoporous bowl-shaped polydopamine nanoparticles grafted with quaternized polymer brushes and coupled with glucose oxidase (GOx) and catalase (CAT). Stemming from the GOx-CAT cascade reaction in diabetic wound microenvironment, they can perform robust chemotactic motion towards both high glucose regions, where bacteria proliferation predominantly occurs, and elevated H2O2 levels, which bacterial metabolism produced. This enables the nanomotors to facilitate targeted migration towards bacteria-rich regions and simultaneous downregulation of glycemic levels, as well as to significantly enhance the electrostatic interaction between antibacterial components and bacteria. Consequently, the nanomotors exhibit amplified contact-killing effects of their attached cationic molecules, leading to an almost 10-fold enhancement in antibacterial efficacy compared to previous counterparts. The in vivo experiments approved that the nanomotors demonstrated the accelerated healing of infected diabetic wounds by S. aureus and biosafety. The results herein provide an insight into the clinical treatment of infected diabetic wounds.

Unraveling the immunomodulatory and metabolic effects of bioactive glass S53P4 on macrophages in vitro

Macrophage metabolism is closely linked to their phenotype and function, which is why there is growing interest in studying the metabolic reprogramming of macrophages. Bioactive glass (BG) S53P4 is a bioactive material used especially in bone applications. Additionally, BG S53P4 has been shown to affect macrophages, but the mechanisms through which the possible immunomodulatory effects are conveyed remain unclear. According to the results presented here, the lipopolysaccharide (LPS) induced suppression in oxidative phosphorylation is rescued in macrophages cultured with BG S53P4 before the inflammatory stimulus. Additionally, BG S53P4-exposed macrophages expressed lower mRNA levels of inflammatory cytokines Il6 and Il1b, as well as demonstrated decreased activation of inflammatory interferon regulatory factor (IRF) and NF-κB pathways and nitrogen oxide secretion in response to LPS. These results did not rely on cells being in direct contact with the material as similar effects were observed in the presence of BG S53P4-conditioned medium. Our findings link the immunomodulatory properties of BG S53P4 and macrophage metabolism, which improves our understanding of the mechanisms underlying the clinical efficacy of bioactive glasses.

Photo-controlled multifunctional hydrogel for photothermal sterilization and microenvironment amelioration of infected diabetic wounds

Diabetic foot ulcers are linked to a high disability rate, with no effective treatment currently available. Addressing infection, reducing oxidative stress, and safely managing chronic inflammation remain major challenges. In this study, a composite hydrogel dressing was developed using natural substances or clinically approved components (dopamine, D-alpha-tocopheryl polyethylene glycol succinate, and rhein). Upon near-infrared laser irradiation, the composite system rapidly heats and solidifies into a gel with photothermal antibacterial properties. Additionally, the decomposition of hydrogen peroxide releases oxygen, alleviating wound hypoxia. The hydrogel exhibited strong bactericidal activity against multiple bacterial strains. Without laser irradiation, the hydrogel effectively scavenged various free radicals and intracellular reactive oxygen species, restoring redox balance. Furthermore, it significantly reduced the expression of inflammatory cytokines, including interleukin-6 and interleukin-1β. In a diabetic mouse wound model infected with S. aureus, the mild photothermal therapy, combined with the antibacterial action of rhein, effectively managed bacterial infections, reduced inflammation, and promoted wound healing. Consequently, the photo-controlled therapeutic approach, offering antibacterial, antioxidant, and anti-inflammatory effects, holds promise for the effective treatment and management of infected diabetic wounds.

Engineering Stimuli-Responsive Materials for Precision Medicine

Over the past decade, precision medicine has garnered increasing attention, making significant strides in discovering new therapeutic drugs and mechanisms, resulting in notable achievements in symptom alleviation, pain reduction, and extended survival rates. However, the limited target specificity of primary drugs and inter-individual differences have often necessitated high-dosage strategies, leading to challenges such as restricted deep tissue penetration rates and systemic side effects. Material science advancements present a promising avenue for these issues. By leveraging the distinct internal features of diseased regions and the application of specific external stimuli, responsive materials can be tailored to achieve targeted delivery, controllable release, and specific biochemical reactions. This review aims to highlight the latest advancements in stimuli-responsive materials and their potential in precision medicine. Initially, we introduce disease-related internal stimuli and capable external stimuli, elucidating the reaction principles of responsive functional groups. Subsequently, we provide a detailed analysis of representative pre-clinical achievements of stimuli responsive materials across various clinical applications, including enhancements in the treatment of cancers, injury diseases, inflammatory diseases, infection diseases, and high-throughput microfluidic biosensors. Finally, we discuss some clinical challenges, such as off-target effects, long-term impacts of nano-materials, potential ethical concerns, and offer insights into future perspectives of stimuli-responsive materials.

Programmed BRD9 Degradation and Hedgehog Signaling Activation via Silk-Based Core-Shell Microneedles Promote Diabetic Wound Healing

Wound healing impairment in diabetes mellitus is associated with an excessive inflammatory response and defective regeneration capability with suppressed Hedgehog (Hh) signaling. The bromodomain protein BRD9, a subunit of the non-canonical BAF chromatin-remodeling complex, is critical for macrophage inflammatory response. However, whether the epigenetic drug BRD9 degrader can attenuate the sustained inflammatory state of wounds in diabetes remains unclear. Without a bona fide immune microenvironment, Hh signaling activation fails to effectively rescue the suppressed proliferative ability of dermal fibroblasts and the vascularization of endothelial cells. Therefore, a silk-based core-shell microneedle (MN) patch is proposed to dynamically modulate the wound immune microenvironment and the regeneration process. Specifically, the BRD9 degrader released from the shell of the MNs mitigated the excessive inflammatory response in the early phase. Subsequently, the positively charged Hh signaling agonist is released from the negatively charged core of the silk fibroin nanofibers and promotes the phase transition from inflammation to regeneration, including re-epithelialization, collagen deposition, and angiogenesis. These findings suggest that the programmed silk-based core-shell MN patch is an ideal therapeutic strategy for effective skin regeneration in diabetic wounds.

NIR-II Image-Guided Wound Healing in Hypoxic Diabetic Foot Ulcers: The Potential of Ergothioneine-Luteolin-Chitin Hydrogels

Hypoxic diabetic foot ulcers (HDFUs) pose a challenging chronic condition characterized by oxidative stress damage, bacterial infection, and persistent inflammation. This study introduces a novel therapeutic approach combining ergothioneine (EGT), luteolin (LUT), and quaternized chitosan oxidized dextran (QCOD) to address these challenges and facilitate wound healing in hypoxic DFUs. In vitro, assessments have validated the biosafety, antioxidant, and antimicrobial properties of the ergothioneine-luteolin-chitin (QCOD@EGT-LUT) hydrogel. Furthermore, near-infrared II (NIR-II) fluorescence image-guided the application of QCOD@EGT-LUT hydrogel in simulated HDFUs. Mechanistically, QCOD@EGT-LUT hydrogel modulates the diabetic wound microenvironment by reducing reactive oxygen species (ROS). In vivo studies demonstrated increased expression of angiogenic factors mannose receptor (CD206) and latelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), coupled with decreased inflammatory factors tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), thereby promoting diabetic wound healing through up-regulation of transforming growth factor β-1 (TGF-β1).

High-throughput screening-based design of multifunctional natural polyphenol nano-vesicles to accelerate diabetic wound healing

Oxidative stress is a major pathological factor that impedes the diabetic wound healing process. Procyanidins (PC) form nanoparticle-vesicles (PPNs) through hydrogen bonding and exhibit good drug delivery capability; however, their application in diabetic wounds is unsatisfactory. To meet the antioxidant needs for treating, high-throughput screening in the natural product library (NPL) under in vitro oxidative stress conditions was conducted to enhance the antioxidant activity of PPNs. HUVECs treated with tert-Butyl Hydroperoxide (TBHP) were established as screening model in vitro. Baicalein (BAI) was identified from over 600  products in the library as the most effective one to combat oxidative stress. Further study showed that PC and BAI may react in equal proportions to synthesize new vesicles, named BAI-PC Polyphenolic nanovesicles (BPPNs), which possess reactive oxygen species (ROS) responsive and antioxidant effects. Network pharmacology indicated that in diabetic wounds, the target genes of PC are mainly enriched in the vascular endothelial growth factor (VEGF)-related pathways, while BAI primarily regulates tyrosine phosphorylation. The complementarity between the two has been validated in both in vitro and in vivo experiments. In summary, the antioxidant drug BAI, identified through high-throughput screening of NPL, could optimize the biological function of PPNs; the newly-synthesized BPPNs may accelerate diabetic wound healing through dual mechanisms of promoting angiogenesis and combating oxidative stress.

Exosome-based cell therapy for diabetic foot ulcers: Present and prospect

Diabetic foot ulcers (DFUs) represent a serious complication of diabetes with high incidence, requiring intensive treatment, prolonged hospitalization, and high costs. It poses a severe threat to the patient's life, resulting in substantial burdens on patient and healthcare system. However, the therapy of DFUs remains challenging. Therefore, exploring cell-free therapies for DFUs is both critical and urgent. Exosomes, as crucial mediators of intercellular communication, have been demonstrated potentially effective in anti-inflammation, angiogenesis, cell proliferation and migration, and collagen deposition. These functions have been proven beneficial in all stages of diabetic wound healing. This review aims to summarize the role and mechanisms of exosomes from diverse cellular sources in diabetic wound healing research. In addition, we elaborate on the challenges for clinical application, discuss the advantages of membrane vesicles as exosome mimics in wound healing, and present the therapeutic potential of exosomes and their mimetic vesicles for future clinical applications.

Zinc-based Polyoxometalate Nanozyme Functionalized Hydrogels for optimizing the Hyperglycemic-Immune Microenvironment to Promote Diabetic Wound Regeneration

BACKGROUND

In diabetic wounds, hyperglycemia-induced cytotoxicity and impaired immune microenvironment plasticity directly hinder the wound healing process. Regulation of the hyperglycemic microenvironment and remodeling of the immune microenvironment are crucial.

RESULTS

Here, we developed a nanozymatic functionalized regenerative microenvironmental regulator (AHAMA/CS-GOx@Zn-POM) for the effective repair of diabetic wounds. This novel construct integrated an aldehyde and methacrylic anhydride-modified hyaluronic acid hydrogel (AHAMA) and chitosan nanoparticles (CS NPs) encapsulating zinc-based polymetallic oxonate nanozyme (Zn-POM) and glucose oxidase (GOx), facilitating a sustained release of release of both enzymes. The GOx catalyzed glucose to gluconic acid and (H₂O₂), thereby alleviating the effects of the hyperglycemic microenvironment on wound healing. Zn-POM exhibited catalase and superoxide dismutase activities to scavenge reactive oxygen species and H₂O₂, a by-product of glucose degradation. Additionally, Zn-POM induced M1 macrophage reprogramming to the M2 phenotype by inhibiting the MAPK/IL-17 signaling diminishing pro-inflammatory cytokines, and upregulating the expression of anti-inflammatory mediators, thus remodeling the immune microenvironment and enhancing angiogenesis and collagen regeneration within wounds. In a rat diabetic wound model, the application of AHAMA/CS-GOx@Zn-POM enhanced neovascularization and collagen deposition, accelerating the wound healing process.

CONCLUSIONS

Therefore, the regenerative microenvironment regulator AHAMA/CS-GOx@Zn-POM can achieve the effective conversion of a pathological microenvironment to regenerative microenvironment through integrated control of the hyperglycemic-immune microenvironment, offering a novel strategy for the treatment of diabetic wounds.

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.

Nano-enzyme functionalized hydrogels promote diabetic wound healing through immune microenvironment modulation

Non-healing diabetic wounds often culminate in amputation and mortality. The main pathophysiological features in diabetic wounds involve the accumulation of M1-type macrophages and excessive oxidative stress. In this study, we engineered a nano-enzyme functionalized hydrogel by incorporating a magnesium ion-doped molybdenum-based polymetallic oxide (Mg-POM), a novel bioactive nano-enzyme, into a GelMA hydrogel, to obtain the GelMA@Mg-POM system to enhance diabetic wound healing. GelMA@Mg-POM was crosslinked using UV light, yielding a hydrogel with a uniformly porous three-dimensional mesh structure. In vitro experiments showed that GelMA@Mg-POM extraction significantly enhanced human umbilical vein endothelial cell (HUVEC) migration, scavenged ROS, improved the inflammatory microenvironment, induced macrophage reprogramming towards M2, and promoted HUVEC regeneration of CD31 and fibroblast regeneration of type I collagen. In in vivo experiments, diabetic rat wounds treated with GelMA@Mg-POM displayed enhanced granulation tissue genesis and collagen production, as evidenced by HE and Masson staining. Immunohistochemistry demonstrated the ability of GelMA@Mg-POM to mitigate macrophage-associated inflammatory responses and promote angiogenesis. Overall, these findings suggest that GelMA@Mg-POM holds significant promise as a biomaterial for treating diabetic wounds.

Extracellular matrix-inspired biomaterials for wound healing

Diabetic foot ulcers (DFU) are a debilitating and life-threatening complication of Diabetes Mellitus. Ulceration develops from a combination of associated diabetic complications, including neuropathy, circulatory dysfunction, and repetitive trauma, and they affect approximately 19-34% of patients as a result. The severity and chronic nature of diabetic foot ulcers stems from the disruption to normal wound healing, as a result of the molecular mechanisms which underly diabetic pathophysiology. The current standard-of-care is clinically insufficient to promote healing for many DFU patients, resulting in a high frequency of recurrence and limb amputations. Biomaterial dressings, and in particular those derived from the extracellular matrix (ECM), have emerged as a promising approach for the treatment of DFU. By providing a template for cell infiltration and skin regeneration, ECM-derived biomaterials offer great hope as a treatment for DFU. A range of approaches exist for the development of ECM-derived biomaterials, including the use of purified ECM components, decellularisation and processing of donor/ animal tissues, or the use of in vitro-deposited ECM. This review discusses the development and assessment of ECM-derived biomaterials for the treatment of chronic wounds, as well as the mechanisms of action through which ECM-derived biomaterials stimulate wound healing.

Nanozymes for the Therapeutic Treatment of Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are chronic, refractory wounds caused by diabetic neuropathy, vascular disease, and bacterial infection, and have become one of the most serious and persistent complications of diabetes mellitus because of their high incidence and difficulty in healing. Its malignancy results from a complex microenvironment that includes a series of unfriendly physiological states secondary to hyperglycemia, such as recurrent infections, excessive oxidative stress, persistent inflammation, and ischemia and hypoxia. However, current common clinical treatments, such as antibiotic therapy, insulin therapy, surgical debridement, and conventional wound dressings all have drawbacks, and suboptimal outcomes exacerbate the financial and physical burdens of diabetic patients. Therefore, development of new, effective and affordable treatments for DFU represents a top priority to improve the quality of life of diabetic patients. In recent years, nanozymes-based diabetic wound therapy systems have been attracting extensive interest by integrating the unique advantages of nanomaterials and natural enzymes. Compared with natural enzymes, nanozymes possess more stable catalytic activity, lower production cost and greater maneuverability. Remarkably, many nanozymes possess multienzyme activities that can cascade multiple enzyme-catalyzed reactions simultaneously throughout the recovery process of DFU. Additionally, their favorable photothermal-acoustic properties can be exploited for further enhancement of the therapeutic effects. In this review we first describe the characteristic pathological microenvironment of DFU, then discuss the therapeutic mechanisms and applications of nanozymes in DFU healing, and finally, highlight the challenges and perspectives of nanozyme development for DFU treatment.

Gases and gas-releasing materials for the treatment of chronic diabetic wounds

Chronic non-healing wounds are a common consequence of skin ulceration in diabetic patients, with severe cases such as diabetic foot even leading to amputations. The interplay between pathological factors like hypoxia-ischemia, chronic inflammation, bacterial infection, impaired angiogenesis, and accumulation of advanced glycosylation end products (AGEs), resulting from the dysregulation of the immune microenvironment caused by hyperglycemia, establishes an unending cycle that hampers wound healing. However, there remains a dearth of sufficient and effective approaches to break this vicious cycle within the complex immune microenvironment. Consequently, numerous scholars have directed their research efforts towards addressing chronic diabetic wound repair. In recent years, gases including Oxygen (O2), Nitric oxide (NO), Hydrogen (H2), Hydrogen sulfide (H2S), Ozone (O3), Carbon monoxide (CO) and Nitrous oxide (N2O), along with gas-releasing materials associated with them have emerged as promising therapeutic solutions due to their ability to regulate angiogenesis, intracellular oxygenation levels, exhibit antibacterial and anti-inflammatory effects while effectively minimizing drug residue-induced damage and circumventing drug resistance issues. In this review, we discuss the latest advances in the mechanisms of action and treatment of these gases and related gas-releasing materials in diabetic wound repair. We hope that this review can provide different ideas for the future design and application of gas therapy for chronic diabetic wounds.

Exploring shared therapeutic targets in diabetic cardiomyopathy and diabetic foot ulcers through bioinformatics analysis

Advanced diabetic cardiomyopathy (DCM) patients are often accompanied by severe peripheral artery disease. For patients with DCM combined with diabetic foot ulcer (DFU), there are currently no good therapeutic targets and drugs. Here, we investigated the underlying network of molecular actions associated with the occurrence of these two complications. The datasets were downloaded from the Gene Expression Omnibus (GEO) database. We performed enrichment and protein-protein interaction analyses, and screened for hub genes. Construct transcription factors (TFs) and microRNAs regulatory networks for validated hub genes. Finally, drug prediction and molecular docking verification were performed. We identified 299 common differentially expressed genes (DEGs), many of which were involved in inflammation and lipid metabolism. 6 DEGs were identified as hub genes (PPARG, JUN, SLC2A1, CD4, SCARB1 and SERPINE1). These 6 hub genes were associated with inflammation and immune response. We identified 31 common TFs and 2 key miRNAs closely related to hub genes. Interestingly, our study suggested that fenofibrate, a lipid-lowering medication, holds promise as a potential treatment for DCM combined with DFU due to its stable binding to the identified hub genes. Here, we revealed a network involves a common target for DCM and DFU. Understanding these networks and hub genes is pivotal for advancing our comprehension of the multifaceted complications of diabetes and facilitating the development of future therapeutic interventions.