Sustained oxygenation accelerates diabetic wound healing by promoting epithelialization and angiogenesis and decreasing inflammation

A functional cardiac patch with "gas and ion" dual-effect intervention for reconstructing blood microcirculation in myocardial infarction repair

Postinfarction revascularization is critical for repairing the infarcted myocardium and for stopping disease progression. Considering the limitations of surgical intervention, engineered cardiac patches (ECPs) are more effective in establishing rich blood supply networks. For efficacy, ECPs should promote the formation of more mature blood vessels to improve microcirculatory dysfunction and mitigate hypoxia-induced apoptosis. Developing collateral circulation between infarcted myocardium and ECPs for restoring blood perfusion remains a challenge. Here, an ion-conductive composite ECPs (GMA@OSM) with powerful angiogenesis-promoting ability was constructed. Based on dual-effect intervention of oxygen and strontium, the developed ECPs can promote the formation of high-density circulating microvascular network at the infarcted myocardium. In addition, the GMA@OSM possesses effective reactive oxygen species-scavenging capacity and can facilitate electrophysiological repair of myocardium with ionic conductivity. In vitro and in vivo studies indicate that the multifunctional GMA@OSM ECPs form well-developed collateral circulation with infarcted myocardium to protect cardiomyocytes and improve cardiac function. Overall, this study highlights the potential of a multifunctional platform for developing collateral circulation, which can lead to an effective therapeutic strategy for repairing myocardial infarction.

A multifunctional hydrogel loaded with magnesium-doped bioactive glass-induced vesicle clusters enhances diabetic wound healing by promoting intracellular delivery of extracellular vesicles

The treatment of diabetic wounds (DWs) poses a significant medical challenge. Mesenchymal stem cell-derived small extracellular vesicles (sEVs) have demonstrated potential in accelerating healing by delivering growth factors and microRNAs. However, the rapid clearance by the circulatory system limits their concentration and bioavailability within cells. This study employed magnesium-doped bioactive glass (MgBG) to autonomously program sEVs into a vesicle cluster (EPPM), which was subsequently incorporated into a hydrogel to create a comprehensive repair system that enhanced the delivery of both sEVs and MgBG, thereby promoting rapid healing of diabetic wounds. This hydrogel exhibited excellent injectable, self-healing and bioadhesive properties, making it an ideal physical barrier for DWs. In addition, the hydrogels also possessed photoresponsive properties that facilitated their bactericidal activity. The released EPPM significantly increased the intracellular uptake and accumulation of sEVs, with approximately 8.2-fold enhancement in macrophages and 16.7-fold in endothelial cells. The EPPM clusters efficiently induce macrophage M2 polarization, reduce inflammatory responses at the wound site, and recruit cells, thereby promoting angiogenesis and collagen deposition. This integrated repair system provided a new platform for the comprehensive treatment of diabetic wounds.

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

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

Polyaminoglycoside nanosystem expressing antimicrobial peptides for multistage chronic wound management

Chronic wounds are difficult to heal due to pathogenic microbial colonization and dysregulation of healing cascades, necessitating novel therapeutic strategies. This study developed a multifunctional nanosystem by integrating the antimicrobial peptide LL37 with cationic polyaminoglycoside (SS-HPT), constructing a self-sustaining "AMP factory" to achieve multi-stage modulation of the wound healing. Validation through cell-level experiments and in vivo dual models (mechanical injury and bacterial infection) in immunocompromised rats demonstrated the system's unique dual intracellular-extracellular pathogen-killing capability, significantly accelerating the wound healing process. Transcriptomic analysis revealed that its mechanism involves the dual effects of suppressing pro-inflammatory factor expression and activating tissue repair pathways. Histological evidence confirmed that the system promotes angiogenesis, enhances re-epithelialization rates, and guides orderly collagen fiber deposition. This nanosystem, combining efficient AMP delivery and integrated therapeutic strategies, achieves three-dimensional synergy in microbial clearance, immune microenvironment regulation, and tissue matrix remodeling, providing theoretical and technical foundations for a paradigm shift in chronic wound treatment.

A dual-action strategy: Wound microenvironment responsive hydrogel and exosome-mediated glucose regulation enhance inside-out diabetic wound repair

Sustained hyperglycemia induces complex pathological microenvironment in diabetic wounds, significantly hindering wound healing. Most current therapeutic approaches (e.g., hydrogel dressings) have paid little attention to the effect of blood glucose levels on diabetic wound healing. In this study, a synergetic therapeutic strategy including a wound microenvironment responsive, multifunctional hydrogel and the exosome-mediated glucose regulation is developed for diabetic wound treatment. First, a gelatin-dopamine (Gel-DA) crosslinked hyaluronic acid-phenylboronic acid (HA-PBA) hydrogel (GDHP) is constructed with good injectable, self-healing, and adhesive abilities. Such GDHP hydrogel not only can effectively relieve oxidative stress and reduce inflammation, but also promote keratinocyte migration. Then, ciprofloxacin hydrochloride (CIP·H) is loaded to prepare the GDHPC hydrogel that may respond to diabetic wound microenvironment (e.g., low pH, high glucose and reactive oxygen species) and degrade for controlled release of CIP·H, showing on-demand antibacterial properties. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-exos) are administered via tail vein injection in diabetic mice, which may repair injured pancreatic islets by modulating the pancreatic immune microenvironment, thus promoting insulin secretion and further reducing blood glucose levels. By applying this synergetic therapeutic strategy, the full-thickness cutaneous wounds in type 1 diabetic mice heal well and quickly compared to that treated with the GDHPC hydrogel and the hucMSC-exos alone. This promotion effect on wound healing may associate with reducing inflammation and promoting angiogenesis. This study sheds new light on the development of a dual-action strategy that can effectively maintain glucose homeostasis, improve the wound microenvironment, and consequently promote inside-out repair of diabetic wounds, offering a promising therapeutic avenue for future diabetic wound treatment.

Biochemical strategy-based hybrid hydrogel dressing-mediated in situ synthesis of selenoproteins for DFU immunity-microbiota homeostasis regulation

Chronic consequences of diabetes that are most commonly encountered are diabetic foot ulcers (DFUs), driven by microbiota-immune system dyshomeostasis, eventually leading to delayed wound healing. Available therapies, such as systemic or topical administration of anti-inflammatory or antimicrobial agents, are limited due to antibiotic resistance and immune dysfunction. Herein, a hybrid hydrogel dressing is developed as the artificial bioadhesive barrier at wound sites to maintain microbial and immunological homeostasis locally and have potent anti-inflammatory effects. Specifically, Zero-valent selenium nanoparticles are synthesized and encapsulated into the alginate-polyacrylamide interpenetrating hydrogel networks, during which trehalose is adopted to modify the network defects. Besides, as an anti-adhesion agent, trehalose has shown the ability to prevent immune degradation by reducing bacteria binding to HUVECs. The obtained hybrid hydrogel dressing serves as a physical barrier against microbiome invasion, further regulates the composition of the wound microbiome to restore microbial immune homeostasis at the wound site, and cooperatively relieves DFU-associated symptoms. Meanwhile, the hydrogel dressing can synthesize selenoproteins in situ based on biochemical strategies and significantly reduce the secretion of proinflammatory cytokines. The proposed biochemical strategy based on the hybrid hydrogel dressings can efficiently restore microbiota-immune homeostasis in the wounds, presenting a promising approach for DFU therapy in clinics.

Micro/nanomotors for active inflammatory disease therapy

Inflammation is a carefully orchestrated response of the immune system to repair injured tissues and clear various damage factors. However, dysregulated inflammation can eventually contribute to the development and progression of various inflammatory diseases. Although anti-inflammatory drugs have demonstrated certain therapeutic efficacy in clinical settings, significant limitations still persist, highlighting the necessity for the development of improved approaches to address complex inflammatory conditions. Micro/nanomotors (MNMs) have shown significant promise for applications in the biomedical field due to their micro/nano-scale sizes and autonomous movement. Unlike traditional nanoparticles, which exhibit passive diffusion in biological fluids, MNMs can convert external energy into a driving force for self-propulsion. This capability not only enhances the tissue penetration depth and retention rates but also facilitates interaction with inflammatory lesions. Recent efforts have suggested that MNMs for inflammatory disease therapy could provide an efficient therapeutic effect. Herein, we mainly introduce the recent advances in inflammatory disease therapy based on MNMs. We conclude by discussing both the obstacles and potential opportunities for MNMs innovations in addressing inflammation.

An Intelligent and Conductive Hydrogel with Multiresponsive and ROS Scavenging Properties for Infection Prevention and Anti-Inflammatory Treatment Assisted by Electrical Stimulation for Diabetic Wound

Diabetic wounds experience a hyperglycemic, hypoxic environment, combined with ongoing oxidative stress and inflammatory imbalances, significantly disrupts normal healing process. Advanced hydrogels have been considered one of the most exciting medical biomaterials for the potential in wounds healing. Herein, a novel conductive hydrogel (HEPP), designed to release nanozyme (PTPPG) in response to its microenvironment, was created to facilitate glucose (Glu) catabolism. Furthermore, the HEPP integrates photodynamic therapy (PDT), photothermal therapy (PTT), and self-cascading reactive oxygen species (ROS) to prevent bacterial infections while ensuring a continuous supply of oxygen (O2) to the wound. The HEPP not only adeptly controls high ROS levels, but also enhances the regulation of inflammation in the wound area via electrical stimulation (ES), thereby promoting healing that is supported by the immune response. Studies conducted in vitro, along with transcriptomic analyses, indicate that ES primarily mitigates inflammation by regulating Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The effects of HEPP combined with ES are primarily connected to their impact on TNF signaling pathways. By reducing the formation of ROS and employing ES to effectively lessen inflammation, this approach offers an innovative method to manage complicated diabetic wounds, ulcers, and a range of inflammatory conditions linked to infections.

Multifunctional nanocomposite hydrogels: an effective approach to promote diabetic wound healing

Diabetes, a metabolic disease that is becoming increasingly severe globally, presents a significant challenge in the medical field. Diabetic wounds are characterized by their chronicity, difficulty healing, and complex microenvironment that harbors multiple adverse factors, including elevated hyperglycemia, persistent inflammation, susceptibility to infections, and oxidative stress, all of which contribute to the impaired healing process. Nanocomposite hydrogels, as materials with unique physicochemical properties and biocompatibility, have gained growing attention in recent years for their potential applications in diabetic wound healing. These hydrogels provide a moist healing environment for wounds and regulate cellular behavior and signaling pathways, promoting wound repair and healing. By introducing specific functional groups and nanoparticles, nanocomposite hydrogels can respond to pathological features of wounds, enabling adaptive drug release. Owing to their diverse bioactive functions, nanocomposite hydrogels are powerful tools for the treatment of diabetic wounds. Thus, this article provides an overview of recent progress in the use of nanocomposite hydrogels for diabetic wound healing.

Gene-engineered polypeptide hydrogels with on-demand oxygenation and ECM-cell interaction mimicry for diabetic wound healing

The treatment of infected diabetic wounds remains a significant clinical challenge due to pathogen infection, excessive inflammation, and impaired angiogenesis with troubled extracellular matrix (ECM) - cell and cell - cell interaction. Herein, we prepared a Janus polypeptide-engineered hydrogel with programmable function driven by self-assembly of the same A domain. The hydrogel was composed of a V8-degradable AC10A layer loaded with hybrid phages (ABC) for precise bacterial inhibition and a PC10ARGD layer loaded with Mn-based mineralized erythrocyte (PEM) for continuous supply oxygen on demand. The results of laser speckle contrast imaging, photoacoustic imaging, and hyperspectral imaging demonstrated that the AC10A@BP-Ce6/PC10AR@EM hydrogel (ABC/PEM) accelerated the reconstruction of normal skin structure by breaking the oxygen diffusion barrier and supplying oxygen on demand to promote angiogenesis and functionalization. In addition, in vitro and in vivo experiment results showed that the ABC/PEM hydrogel can mimic positive ECM - cell interaction to inhibit the polarization of macrophage towards M1-type to slow down the inflammatory process by down-regulated yes-associated protein (YAP), and relieve the mechanical tension of fibroblasts and keratinocytes. Finally, the ABC/PEM hydrogel promotes a healing rate of 98.83 % on day 21 and results in the number of dermal appendages being eight times that of the negative group. This work presents an effective strategy for diabetes-related chronic infected wound management.

Multifunctional coaxial gelatin/polylactic acid three-dimensional nanofibrous scaffolds for diabetic wounds

Diabetes, characterized by hyperglycemia, poses a significant threat to human health. Diabetic wounds exhibit heightened levels of excessive reactive oxygen species (ROS), bacterial infection, hypoxia, and substantial exudate. These factors accelerate the inflammatory phase and impede wound healing, often leading to chronicity. Inadequate wound healing is a common chronic complication of diabetes. In this study, we fabricated three-dimensional (3D) curcumin@(manganese dioxide (MnO2)@(gelatin/polylactic acid (PLA)@ε-polylysine (ε-pl))) (GPPMC) nanofibrous scaffolds dressing using coaxial electrospinning, homogenization, freeze-drying, glutaraldehyde crosslinking, and impregnation techniques. The presented gelatin-based 3D nanofibrous dressing demonstrated superior water absorption capacity, hemostatic proficiency, enhanced cell adhesion and tissue infiltration compared to two-dimensional (2D) counterparts. It also exhibited exceptional compressibility, biocompatibility, prolonged curcumin and ε-pl drug release, as well as scavenging capabilities against ROS, antibacterial efficacy and oxygen generation in vitro. Additionally, this dressing exhibited remarkable wound healing efficacy and anti-inflammatory in vivo. These findings suggested that the developed multifunctional gelatin-based 3D nanofibrous scaffold is a promising candidate for the treatment of diabetic wounds.

Hypoxia-Driven Neurovascular Impairment Underlies Structural-Functional Dissociation in Diabetic Sudomotor Dysfunction

Sudomotor dysfunction in diabetic patients increases the risk of fissures, infections, and diabetic foot ulcers (DFUs), thereby reducing the quality of life. Despite its clinical importance, the mechanisms underlying this dysfunction remain inadequately elucidated. This study addresses this gap by demonstrating that despite structural integrity, sweat glands (SGs) in diabetic individuals with DFUs, and a murine model of diabetic neuropathy (DN), exhibit functional impairments, as confirmed by histological and functional assays. Integrated transcriptome and proteome analysis revealed significant upregulation of the SG microenvironment in response to hypoxia, highlighting potential underlying pathways involved. In addition, histological staining and tissue clearing techniques provided evidence of impaired neurovascular networks adjacent to SGs. Single-cell RNA sequencing unveiled intricate intercellular communication networks among endothelial cells (ECs), neural cells (NCs), and sweat gland cells (SGCs), emphasizing intricate cellular interactions within the SG microenvironment. Furthermore, an in vitro SGC-NC interaction model (SNIM) was employed to validate the supportive role of NCs in regulating SGC functions, highlighting the neurovascular-SG axis in diabetic pathophysiology. These findings confirm the hypoxia-driven upregulation of the SG microenvironment and underscore the critical role of the neurovascular-SG axis in diabetic pathophysiology, providing insights into potential therapeutic targets for managing diabetic complications and improving patient outcomes.

Calcium-ion-driving assembly of polysaccharide deriving from Zizyphus jujuba to hemostatic hydrogel for treating diabetic wound

Due to good biocompatibility and biodegradable, natural polysaccharide-based hydrogels have received worldwide attentions, where polysaccharide polymers were usually chemically modified to meet the specific elastic requirements. However, it remained highly challenging to develop polysaccharide-based hydrogels with desired mechanical properties and biological functions devoid of any structural modifications. Herein, with the coordination of Ca2+ (15.0 mM), the jujuba polysaccharide (JPS, 1 %) was facilely fabricated to a hydrogel (JPS-gel) within 1 min at pH 10, where the residual proteins also played crucial roles on the assembly. The JPS-gel showed outstanding stability and mechanical properties, which were tunable by adjusting the content of Ca2+/JPS. The JPS-gel also revealed excellent biocompatibility, and could expedite the migration and proliferation of healing-related cells, angiogenesis and alleviate inflammation response. More interestingly, the JPS-gel had hemostatic capacity, where the hemostatic time and blood loss in liver incision model were 13 ± 3 s and 6.3 ± 1.6 mg after 120 s treatment with JPS-gel, respectively. All these superiorities endowed JPS-gel high performance healing in diabetic wounds (10 days). Specially, the expressions of inflammation-related genes were downregulated, but gene expressions associated with cell migration and proliferation, and angiogenesis were upregulated, thus uncovering the action mechanism of JPS-gel on accelerating wound contraction.

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

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

Advances in Designer Materials for Chronic Wound Healing

Significance: Nonhealing or chronic wounds represent a significant and growing global health concern, imposing substantial burdens on individuals, health care systems, and economies worldwide. Although the standard-of-care treatment involves the application of wound dressings, most dressing materials are not specifically designed to address the pathological processes underlying chronic wounds. This review highlights recent advances in biomaterial design tailored to chronic wound healing. Recent Advances: Chronic wounds are characterized by persistent inflammation, impaired granulation tissue formation, and delayed re-epithelialization. Newly developed designer materials aim to manage reactive oxygen species and extracellular matrix degradation to suppress inflammation while promoting vascularization, cell proliferation, and epithelial migration to accelerate tissue repair. Critical Issues: Designing optimal materials for chronic wounds remains challenging due to the diverse etiology and a multitude of pathological mechanisms underlying chronic wound healing. While designer materials can target specific aberrations, designing a materials approach that restores all aberrant wound-healing processes remains the Holy Grail. Addressing these issues requires a deep understanding of how cells interact with the materials and the complex etiology of chronic wounds. Future Directions: New material approaches that target wound mechanics and senescence to improve chronic wound closure are under development. Layered materials combining the best properties of the approaches discussed in this review will pave the way for designer materials optimized for chronic wound healing.

Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: a narrative review

Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.

Sustained ROS Scavenging and Pericellular Oxygenation by Lignin Composites Rescue HIF-1α and VEGF Levels to Improve Diabetic Wound Neovascularization and Healing

Although delayed wound healing is an important clinical complication in diabetic patients, few targeted treatments are available, and it remains a challenge to promote diabetic wound healing. Impaired neovascularization is one of the prime characteristics of the diabetic phenotype of delayed wound healing. Additionally, increased levels of reactive oxygen species (ROS) and chronic low-grade inflammation and hypoxia are associated with diabetes, which disrupts mechanisms of wound healing. We developed lignosulfonate composites with several wound healing properties, including sustained oxygen release through calcium peroxide nanoparticles and reactive oxygen species and free radical scavenging by thiolated lignosulfonate nanoparticles. Sustained release of oxygen and ROS-scavenging by these composites promoted endothelial cell (EC) branching and characteristic capillary-like network formation under high glucose conditions in vitro. Gene co-expression network analysis of RNA-sequencing results from ECs cultured on lignin composites showed regulation of inflammatory pathways, alongside the regulation of angiogenic hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth (VEGF) factor pathways. In vivo, lignosulfonate composite treatment promoted VEGF expression and angiogenesis in full thickness skin wounds in diabetic mice, a model of delayed wound healing. Treatment of diabetic wounds with lignosulfonate composites also promoted faster epithelial gap closure and increased granulation tissue deposition by day 7 post-wounding, with a higher presence of pro-healing type macrophages. Our findings demonstrate that lignosulfonate composites promote diabetic wound healing without requiring additional drugs. This highlights the potential of functionalized lignosulfonate for wound healing applications that require balanced antioxidation and controlled oxygen release. STATEMENT OF SIGNIFICANCE: The lignosulfonate composites developed in this study offer a promising solution for delayed wound healing in diabetic patients. By effectively addressing key factors contributing to the multifaceted pathophysiology of the diabetic wounds, including impaired neovascularization, increased ROS levels, and chronic inflammation and wound proteolysis, these composites demonstrate significant potential for promoting wound repair and reducing the complications associated with diabetic wounds. The unique combination of pro-angiogenic, oxygen-releasing, ECM remodeling and antioxidant properties in these lignosulfonate-based materials highlights their potential as a valuable therapeutic option, providing a multi-pronged approach to diabetic wound healing without the need for additional drugs.

Targeted delivery of engineered adipose-derived stem cell secretome to promote cardiac repair after myocardial infarction

Stem cell secretome offers a promising alternative to stem cell transplantation for treating myocardial infarction (MI). However, its clinical application faces two major challenges: how to enhance the levels of growth factors within the secretome to promote cardiac cell survival and vascularization, and how to efficiently deliver the secretome to the infarcted heart during the acute MI phase without risking rupture of the weakened myocardium. To address these challenges, we upregulated angiogenic growth factors in the secretome from adipose-derived stem cells (ADSC-secretome) by conditioning the cells under hypoxia and with insulin-like growth factor 1 (IGF-1). Our results show that exposure to 1 % O₂ condition significantly increased the expression of VEGF, bFGF, and PDGF-BB compared to 5 % O₂ condition. Co-treatment with IGF-1 further elevated the levels of these growth factors and, notably, reduced the secretion of pro-inflammatory cytokines such as TNFα, IL-1β, and IL-6 from the ADSCs. To rapidly and specifically deliver the secretome to the infarcted heart during acute MI, we encapsulated it within ischemia-targeting nanoparticles. These nanoparticles, designed for intravenous injection, preferentially accumulated in the infarcted region. The treatment significantly improved cardiac cell survival, tissue vascularization, and cardiac function. These findings suggest that ADSC secretome, enriched with angiogenic growth factors, holds strong potential for facilitating cardiac repair following MI.

Cellulose-Based Nanofibers Infused with Biotherapeutics for Enhanced Wound-Healing Applications

Nanofibers fabricated from various materials such as polymers, carbon, and semiconductors have been widely used for wound healing and tissue engineering applications due to their excellent nontoxic, biocompatible, and biodegradable properties. Nanofibers with a diameter in the nanometer range possess a larger surface area per unit mass permitting easier addition of surface functionalities and release of biotherapeutics incorporated compared with conventional polymeric microfibers. Henceforth, nanofibers are a choice for fabricating scaffolds for the management of wound healing. Nanofibrous scaffolds have emerged as a promising method for fabricating wound dressings since they mimic the fibrous dermal extracellular matrix milieu that offers structural support for wound healing and functional signals for guiding tissue regeneration. Cellulose-based nanofibers have gained significant attention among researchers in the fabrication of on-site biodegradable scaffolds fortified with biotherapeutics in the management of wound healing. Cellulose is a linear, stereoregular insoluble polymer built from repeated units of d-glucopyranose linked with 1,4-β glycoside bonds with a complex and multilevel supramolecular architecture. Cellulose is a choice and has been used by various researchers due to its solubility in many solvents and its capacity for self-assembly into nanofibers, facilitating the mimicry of the natural extracellular matrix fibrous architecture and promoting substantial water retention. It is also abundant and demonstrates low immunogenicity in humans due to its nonanimal origins. To this end, cellulose-based nanofibers have been studied for protein delivery, antibacterial activity, and biosensor applications, among others. Taken together, this review delves into an update on cellulose-based nanofibers fused with bioactive compounds that have not been explored considerably in the past few years.

Advances in oxygen-releasing matrices for regenerative engineering applications

In recent years, the effects of hypoxia on tissue repair have received wider attention with the deepening of tissue engineering research. Various oxygen supply strategies have wider applications in the field of tissue repair. Currently, commonly used methods of oxygen supply for defective tissues include hyperbaric oxygen (HBO) and oxygen-releasing materials. Between them, oxygen-releasing materials continuously and efficiently release oxygen from within the defective tissue. Compared with HBO, which may cause oxidative stress in healthy tissues, supplying oxygen via oxygen-releasing materials is safer because of their oxygen-releasing in situ and specific oxygen supply characteristics. However, there still exist some problems in the study of oxygen-releasing materials, such as cytotoxicity and the shortage of oxygen-releasing time. The current reviews on oxygen-releasing materials mostly elaborate on the principles of oxygen-releasing materials and lack a review of their preparation methods and applications. In this paper, different types of oxygen-releasing materials, such as hydrogels, microspheres, and layers, are reviewed concerning their applications, structures, current development status, and challenges.

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

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

Targeting S100A12 to Improve Angiogenesis and Accelerate Diabetic Wound Healing

Long-term inflammation and impaired angiogenesis are thought to be the causes of delayed healing or nonhealing of diabetic wounds. S100A12 is an essential pro-inflammatory factor involved in inflammatory reactions and serves as a biomarker for various inflammatory diseases. However, whether high level of S100A12 exists in and affects the healing of diabetic wounds, as well as the underlying molecular mechanisms, remain unclear. In this study, we found that the serum concentration of S100A12 is significantly elevated in patients with type 2 diabetes. Exposure of stratified epidermal cells to high glucose environment led to increased expression and secretion of S100A12, resulting in impaired endothelial function by binding to the advanced glycation endproducts (RAGE) or Toll-like receptor 4 (TLR4) on endothelial cell. The transcription factor Krüpple-like Factor 5 (KLF5) is highly expressed in the epidermis under high glucose conditions, activating the transcriptional activity of the S100A12 and boost its expression. By establishing diabetic wounds model in alloxan-induced diabetic rabbit, we found that local inhibition of S100A12 significantly accelerated diabetic wound healing by promoting angiogenesis. Our results illustrated the novel endothelial-specific injury function of S100A12 in diabetic wounds and suggest that S100A12 is a potential target for the treatment of diabetic wounds.

Amyloid-Templated Ceria Nanozyme Reinforced Microneedle for Diabetic Wound Treatments

Amyloid fibrils have emerged as excellent templates and building blocks for the development of ordered functional materials with considerable potential in biomedical applications. Here, lysozyme amyloid fibrils (Lys-AFs) are employed as templates for the in situ synthesis of ceria nanozymes (Lys-AFs-Ceria) with ultrafine dimensions, an optimized Ce3+/Ce4+ ratio, and uniform distribution on the fibril surface, addressing the challenges of low catalytic efficiency and high susceptibility to aggregation typical of traditional methods. As a proof of concept, it is further applied Lys-AFs-Ceria to develop hydrogel/microneedle for treating bacteria-infected diabetic wounds via non-covalent interactions between polyphenols and amyloid fibrils incorporating glucose oxidase (GOX). The hydrogel/microneedle facilitates superoxide dismutase and catalase cascade catalysis by Lys-AFs-Ceria, and integrates GOX-mediated glucose consumption, synergistically achieving glucose reduction, reactive oxygen species elimination, and hypoxia alleviation in the diabetic wound infection microenvironment. In addition to antibacterial properties and tissue regeneration promotion of Lys-AFs scaffold, Lys-AFs-Ceria regulates macrophages polarization toward an anti-inflammatory M2 state. Collectively, these attributes contribute to the enhanced efficacy of diabetic wound healing, with in vivo studies demonstrating increased healing efficiency following a single application, and more in general an effective strategy toward high-catalytic and stable nanozymes.

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.

Dual-layer microneedles with NO/O2 releasing for diabetic wound healing via neurogenesis, angiogenesis, and immune modulation

Diabetic wounds present multiple functional impairments, including neurovascular dysregulation, oxidative imbalance, and immune dysfunction, making wound healing particularly challenging, while traditional therapeutical strategies fail to address these complex issues effectively. Herein, we propose a strategy utilizing dual-layer microneedles to deliver therapeutic gases by modulating neurovascular coupling and immune functions for diabetic wound treatment. The microneedle can respond to reactive oxygen species (ROS) in the diabetic microenvironment and subsequently generate oxygen (O2) and nitric oxide (NO). These gases comprehensively promote neuro-vascular regeneration, reduce oxidative stress levels, and attenuate inflammation. In vivo studies demonstrate that the microneedle can accelerate diabetic wound healing by modulating neurovascular regeneration and inflammatory processes. Transcriptomic analyses further validate the involvement of related advantageous signaling pathways. The potential mechanism involves the activation of the PI3K-AKT-mTOR pathway to facilitate autophagy, ultimately accelerating the healing process. Thus, our multifunctional dual-layer microneedles provide an effective strategy for treating diabetic wounds.

Silk Nonwoven Fabric-Based Dressing with Antibacterial and ROS-Scavenging Properties for Modulating Wound Microenvironment and Promoting Diabetic Wound Healing

The microenvironment of diabetic wounds is exceptionally complex, characterized notably by persistent bacterial infections and the excessive production of reactive oxygen species (ROS). Traditional treatment methods often fall short of achieving ideal results. Consequently, there is an urgent need to develop and implement more advanced and efficient treatment strategies to effectively address the complexity and recalcitrance of diabetic wounds. This study pioneers a novel approach by fabricating a silk fibroin-based nonwoven dressing (SF-Ag-HCA) under neutral conditions, integrating silver ions with dihydrocaffeic acid-modified silk fibroin. Uniquely, this dressing achieves dual functionality: exceptional antibacterial efficacy against common pathogens (E. coli, S. aureus, P. aeruginosa) and robust ROS-scavenging capabilities, effectively mitigating oxidative stress and promoting immune homeostasis. The SF-Ag-HCA dressing not only surpasses conventional materials in regulating the wound microenvironment but also accelerates re-epithelialization and collagen deposition. Animal studies further validate its superior performance in healing diabetic and infected wounds compared to commercial alternatives. This innovative dressing represents a significant advancement in wound care, offering an integrated, cost-effective solution tailored for complex chronic wound management.

CaMKK2 Regulates Macrophage Polarization Induced by Matrix Stiffness: Implications for Shaping the Immune Response in Stiffened Tissues

Macrophages are essential for immune responses and maintaining tissue homeostasis, exhibiting a wide range of phenotypes depending on their microenvironment. The extracellular matrix (ECM) is a vital component that provides structural support and organization to tissues, with matrix stiffness acting as a key regulator of macrophage behavior. Using physiologically relevant 3D stiffening hydrogel models, it is found that increased matrix stiffness alone promoted macrophage polarization toward a pro-regenerative phenotype, mimicking the effect of interleukin-4(IL-4) in softer matrices. Blocking Calcium/calmodulin-dependent kinase kinase 2 (CaMKK2) selectively inhibited stiffness-induced macrophage polarization without affecting IL-4-driven pro-regenerative pathways. In functional studies, CaMKK2 deletion prevented M2-like/pro-tumoral polarization caused by matrix stiffening, which in turn hindered tumor growth. In a murine wound healing model, loss of CaMKK2 impaired matrix stiffness-mediated macrophage accumulation, ultimately disrupting vascularization. These findings highlight the critical role of CaMKK2 in the macrophage mechanosensitive fate determination and gene expression program, positioning this kinase as a promising therapeutic target to selectively modulate macrophage responses in pathologically stiff tissues.

Sustained-Release H2S Nanospheres Regulate the Inflammatory Microenvironment of Wounds, Promote Angiogenesis and Collagen Deposition, and Accelerate Diabetic Wound Healing

Diabetic wounds are blocked in the inflammatory stage, growth factors are degraded, and blood vessels are difficult to regenerate, leading to continuous necrosis and nonhealing of the wound. Hydrogen sulfide (H2S) plays an important role in the pathophysiological process of wound healing and has a long history of treating skin diseases. Although the sulfide salt solution is the preferred donor of exogenous H2S, its rapid release rate, excess production, and difficulty in accurately controlling the dose limit its use. Herein, we developed H2S sustained-release nanospheres NaHS@MS@LP for the treatment of diabetic wounds. NaHS@MS@LP nanosphere was composed of a NaHS-loaded mesoporous silicon core and a DSPE-PEG liposome outer membrane. When NaHS@MS@LP nanospheres were used to treat the wound of diabetic rats, mesoporous silicon was delivered into the cells and the loaded NaHS slowly released H2S through hydrolysis, participating in all stages of wound healing. In conclusion, NaHS@MS@LP nanospheres regulated the inflammatory microenvironment of wound skin by inducing the transformation of macrophages into M2 type and promoted angiogenesis and collagen deposition to accelerate wound healing in diabetic rats. Our findings provide strategies for the treatment of chronic wounds, including but not limited to diabetic wounds.

Electrospinning in promoting chronic wound healing: materials, process, and applications

In the field of wound treatment, chronic wounds pose a significant burden on the medical system, affecting millions of patients annually. Current treatment methods often fall short in promoting effective wound healing, highlighting the need for innovative approaches. Electrospinning, a technique that has garnered increasing attention in recent years, shows promise in wound care due to its unique characteristics and advantages. Recent studies have explored the use of electrospun nanofibers in wound healing, demonstrating their efficacy in promoting cell growth and tissue regeneration. Researchers have investigated various materials for electrospinning, including polymers, ceramics, carbon nanotubes (CNTs), and metals. Hydrogel, as a biomaterial that has been widely studied in recent years, has the characteristics of a cell matrix. When combined with electrospinning, it can be used to develop wound dressings with multiple functions. This article is a review of the application of electrospinning technology in the field of wound treatment. It introduces the current research status in the areas of wound pathophysiology, electrospinning preparation technology, and dressing development, hoping to provide references and directions for future research.

CDK1-loaded extracellular vesicles promote cell cycle to reverse impaired wound healing in diabetic obese mice

Small extracellular vesicles (sEVs) mediate intercellular signaling to coordinate the proliferation of cell types that promote re-epithelialization of skin following injury. Cyclin-dependent kinase 1 (CDK1) drives cell division and is a key regulator of entry to the cell cycle. To understand the potential of sEV-mediated delivery of CDK1 to reverse impaired wound healing, we generated CDK1-loaded sEVs (CDK1-sEVs) and evaluated their ability to mediate cell proliferation, re-epithelialization, and downstream signaling responses in the wound bed. We found that treatment of human keratinocytes with CDK1-sEVs increased phosphorylation of the CDK1 target, eukaryotic translation inhibition factor 4E-binding protein 1 (4E-BP1), and histone H3 within 24 h via AKT and ERK phosphorylation, driving increased proliferation and cell migration. Treatment of the wound bed of diabetic obese mice, a model of delayed wound healing, with a single dose of CDK1-sEVs accelerated wound closure, increased re-epithelialization, and promoted the proliferation of keratinocytes. These studies show that delivery of CDK1 by sEVs can stimulate selective and transient proliferation of cell types that increase re-epithelialization and promote proliferation of keratinocytes to accelerate wound healing.

Ultrasound-Triggered Oxygen Release System for Accelerating Wound Healing of Diabetic Foot Ulcers

Diabetic foot ulcer (DFU) is a common complication of chronic diabetes mellitus. Oxygen plays a critical role in the healing process of DFU wounds by promoting cell migration and neovascularization. However, clinical hyperbaric oxygen (HBO) therapy predominantly uses systemic oxygen administration, posing challenges in inadequate DFU local oxygen penetration and potential ectopic organs oxygen toxicity. To address these challenges, a strategy to encapsulate oxygen with lipid microbubbles (OMBs) and incorporate them into a body temperature-sensitive heparin-pluronic copolymer hydrogel (HP/OMBs) have been developed. HP/OMBs showed high biocompatibility both in vitro and in vivo. After in situ administration, oxygen can be released from HP/OMBs to the local deep site of the DFU wounds under ultrasound (US) triggering. Thus, given its biocompatibility and practicality, the combined action of HP/OMBs and the US has important translational value in accelerating diabetic chronic wound healing.

Photosynthesis-Inspired NIR-Triggered Fe₃O₄@MoS₂ Core-Shell Nanozyme for Promoting MRSA-Infected Diabetic Wound Healing

Bacterial infections can lead to severe medical complications, including major medical incidents and even death, posing a significant challenge in clinical trauma repair. Consequently, the development of new, efficient, and non-resistant antimicrobial agents has become a priority for medical practitioners. In this study, a stepwise hydrothermal reaction strategy is utilized to prepare Fe3O4@MoS2 core-shell nanoparticles (NPs) with photosynthesis-like activity for the treatment of bacterial infections. The Fe3O4@MoS2 NPs continuously catalyze the production of reactive oxygen species (ROS) from hydrogen peroxide through photosynthesis-like reactions and convert light energy into heat with a photothermal efficiency of 30.30%. In addition, the photosynthetically generated ROS, combined with the iron-induced cell death mechanism of the Fe3O4@MoS2 NPs, confer them with exceptional and broad-spectrum antibacterial properties, achieving antimicrobial activities of up to 98.62% for Staphylococcus aureus, 99.22% for Escherichia coli, and 98.55% for methicillin-resistant Staphylococcus aureus. The composite exhibits good cell safety and hemocompatibility. Finally, a full-thickness diabetic wound model validates the significant pro-healing properties of Fe3O4@MoS2 in chronic diabetic wounds. Overall, the design of photosynthesis-inspired Fe3O4@MoS2 presents new perspectives for developing efficient photothermal nano-enzymatic compounds, offering a promising solution to the challenges of antimicrobial drug resistance and antibiotic misuse.

Hyperbaric oxygen treatment promotes tendon-bone interface healing in a rabbit model of rotator cuff tears

Due to the high-intensity pressure that the shoulder cuff endures, it is prone to traumas and tears. The main critical function of the shoulder cuff muscles is to effectively facilitate shoulder movement and securely maintain the humeral head in the precise center of the joint cavity to prevent superior migration during abduction processes. Shoulder cuff injuries typically involve the muscle-tendon-bone interface, but existing repair techniques do not always guarantee complete and secure healing, leading to retears. Hyperbaric oxygen therapy, as an auxiliary treatment, can significantly promote the muscle-tendon-bone healing process. To explore the impact of hyperbaric oxygen therapy on the bone-tendon interface healing process in a rabbit model specifically designed for shoulder cuff tears, an experiment was conducted on New Zealand white rabbits by performing a full-thickness tear of the supraspinatus tendon in the left shoulder, followed by 2 hours per day of 100% oxygen treatment at 2 absolute atmospheres for 5 days. The results indicate that hyperbaric oxygen therapy significantly enhances vascularization at the interface between the shoulder cuff and tendon-bone, promotes collagen fiber regeneration in the tendon, improves the tensile strength of the tendon-bone complex, and does not have a significant effect on biomechanical stability. This suggests that hyperbaric oxygen therapy has a significant positive impact on the histological and biomechanical healing of shoulder cuff tears in rabbits, expediting the healing process of the tendon-bone interface.

Engineering next-generation oxygen-generating scaffolds to enhance bone regeneration

In bone, an adequate oxygen (O2) supply is crucial during development, homeostasis, and healing. Oxygen-generating scaffolds (OGS) have demonstrated significant potential to enhance bone regeneration. However, the complexity of O2 delivery and signaling in vivo makes it challenging to tailor the design of OGS to precisely meet this biological requirement. We review recent advances in OGS and analyze persisting engineering and translational hurdles. We also discuss the potential of computational and machine learning (ML) models to facilitate the integration of novel imaging data with biological readouts and advanced biomanufacturing technologies. By elucidating how to tackle current challenges using cutting-edge technologies, we provide insights for transitioning from traditional to next-generation OGS to improve bone regeneration in patients.

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

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

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.

Lipid nanoparticle: advanced drug delivery systems for promotion of angiogenesis in diabetic wounds

Diabetic wound is one of the most challenge in healthcare, requiring innovative approaches to promote efficient healing. In recent years, lipid nanoparticle-based drug delivery systems have emerged as a promising strategy for enhancing diabetic wound repair by stimulating angiogenesis. These nanoparticles offer unique advantages, including improved drug stability, targeted delivery, and controlled release, making them promising in enhancing the formation of new blood vessels. In this review, we summarize the emerging advances in the utilization of lipid nanoparticles to deliver angiogenic agents and promote angiogenesis in diabetic wounds. Furthermore, we provide an in-depth exploration of key aspects, including the intricate design and fabrication of lipid nanoparticles, their underlying mechanisms of action, and a comprehensive overview of preclinical studies. Moreover, we address crucial considerations pertaining to safety and the translation of these innovative systems into clinical practice. By synthesizing and analyzing the available knowledge, our review offers valuable insights into the future prospects and challenges associated with utilizing the potential of lipid nanoparticle-based drug delivery systems for promoting robust angiogenesis in the intricate process of diabetic wound healing.

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.

Revolutionizing pressure ulcer regeneration: Unleashing the potential of extracellular matrix-derived temperature-sensitive injectable antioxidant hydrogel for superior stem cell therapy

Pressure ulcers are a common issue in elderly and medically compromised individuals, posing significant challenges in healthcare. Human umbilical cord mesenchymal stem cells (HUMSCs) offer therapeutic benefits like inflammation modulation and tissue regeneration, yet challenges in cell survival, retention, and implantation rates limit their clinical application. Hydrogels in three-dimensional (3D) stem cell culture mimic the microenvironment, improving cell survival and therapeutic efficacy. A thermosensitive injectable hydrogel (adEHG) combining gallic acid-modified hydroxybutyl chitosan (HBC-GA) with soluble extracellular matrix (adECM) has been developed to address these challenges. The hybrid hydrogel, with favorable physical and chemical properties, shields stem cells from oxidative stress and boosts their therapeutic potential by clearing ROS. The adEHG hydrogel promotes angiogenesis, cell proliferation, and collagen deposition, further enhancing inflammation modulation and wound healing through the sustained release of therapeutic factors and cells. Additionally, the adEHG@HUMSC composite induces macrophage polarization towards an M2 phenotype, which is crucial for wound inflammation inhibition and successful healing. Our research significantly propels the field of stem cell-based therapies for pressure ulcer treatment and underscores the potential of the adEHG hydrogel as a valuable tool in advancing regenerative medicine.

Construction of GOx-loaded metal organic frameworks antibacterial composite hydrogels for skin wound healing

Bacterial infections and inflammation severely impede wound healing. Here, we developed a zwitterionic hydrogel incorporating MOF/GOx for pH-responsive, controlled drug release. The multifunctional hydrogel embedded with MOF/GOx was successfully prepared through the Schiff base reaction between the copolymer poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(4-formylphenyl methacrylate)] (PMF) and the branched polyethylenimine (PEI) modified by the zwitterionic monomer ((4-hydroxyphenyl)sulfonyl)(4-(trimethylammonio)butanoyl)amide (AB), which possessed excellent injectable and self-healing ability, a highly sensitive and reversible responsiveness to pH changes, and good biocompatibility. Moreover, the MOF/GOx-PP composite hydrogel under exposure to a slightly acidic environment would rupture, and the slowly released MOF/GOx triggered a cascade-catalyzed reaction that could inhibit and kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and, simultaneously, mouse experiments indicated that the wound healing rate showed 93 % wound closure in 7 days compared to 67 % with controls. The multifunctional antibacterial hydrogel has immense potential as a dressing in the treatment of infected wounds.

Andrias davidianus Derived Glycosaminoglycans Direct Diabetic Wound Repair by Reprogramming Reparative Macrophage Glucolipid Metabolism

Harnessing cross-species regenerative cues to direct human regenerative potential is increasingly recognized as an excellent strategy in regenerative medicine, particularly for addressing the challenges of impaired wound healing in aging populations. The skin mucus of Andrias davidianus plays a critical role in self-protection and tissue repair, yet the fundamental regenerative factors and mechanisms involved remain elusive. Here, this work presents evidence that glycosaminoglycans (GAGs) derived from the skin secretion of Andrias davidianus (SAGs) serve as potent mediators of angiogenesis and inflammatory remodeling, facilitating efficient healing of diabetic wounds. Mechanistic studies reveal that SAGs promote macrophage polarization toward an anti-inflammatory and pro-regenerative phenotype (CD206+/Arg1+) via glucolipid metabolic reprogramming. This process suppresses excessive inflammation and enhances the expression of VEGF and IL-10 to create a facilitative microenvironment for tissue regeneration. Additionally, this work develops SAGs-GelMA composite microspheres that address multiple stages of wound healing, including rapid hemostasis, exudate control, and activation of endogenous regenerative processes. This engineered approach significantly improves the scarless healing of diabetic wounds by facilitating the recruitment and activation of reparative macrophages. The findings offer new insights into the regenerative mechanisms of Andrias davidianus and highlight the potential therapeutic application of SAGs in tissue repair.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

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.

Engineering Gas-Releasing Nanomaterials for Efficient Wound Healing

The escalating prevalence of tissue damage and its associated complications has elicited global apprehension. While nanomaterial-based wound healing exhibits significant potential in terms of curbing infections and surpassing conventional methods, unresolved concerns regarding nanomaterial controllability and precision remain unresolved, jeopardizing its practical applications. In recent years, a unique strategy for creating gas-releasing nanomaterials for wound repair has been proposed, involving the creation of gas-releasing nanomaterials to facilitate wound repair by generating gas donor moieties. The operational spatiotemporal responsiveness and broad-spectrum antibacterial properties of these gases, combined with their inability to generate bacterial resistance like traditional antibiotics, establish their efficacy in addressing chronic non-healing wounds, specifically diabetic foot ulcers (DFUs). In this review, we delve into the intricacies of wound healing process, emphasizing the chemical design, functionality, bactericidal activity, and potential of gas-release materials, encompassing NO, CO, H2S, O2, CO2, and H2, for effective wound healing. Furthermore, we explore the advancements in synergistic therapy utilizing these gases, aiming to enhance our overall comprehension of this field. The insights gleaned from this review will undoubtedly aid researchers and developers in the creation of promising gas-releasing nanomaterials, thus propelling efficient wound healing in the future.

Astragalus polysaccharide/carboxymethyl chitosan/sodium alginate based electroconductive hydrogels for diabetic wound healing and muscle function assessment

Natural polysaccharides with excellent biocompatibility are considered ideal materials for repairing diabetic foot ulcer. However, diabetic foot ulcer is often accompanied by decreased muscle function, even resulting in muscle atrophy. During wound repair, monitoring muscle function at the wound site in real time can identify the decreased muscle strength timely, which is crucial for precise wound rehabilitation. Nevertheless, the majority of hydrogels are primarily utilized for wound healing and lack the capability for electromyography monitoring. Here, we designed a multinetwork hydrogel composed of astragalus polysaccharide, chitosan, and sodium alginate and internally embedded conductive PPy-PDA-MnO2 nanoparticles (P-NPs) loaded with resveratrol (Res) for wound repair and muscle function assessment. The intrinsic hypoglycemic and anti-inflammatory properties of astragalus polysaccharides, combined with the antioxidative and proangiogenic functions of Res, synergistically facilitate wound healing. The multinetwork structure affords the hydrogel excellent mechanical properties. Furthermore, the addition of conductive NPs not only improves the mechanical performance of the hydrogel but also confers electrical conductivity. The conductive hydrogel acts as an epidermal electrode which can be utilized for monitoring of electromyography signals. This novel approach for treating diabetic wounds ultimately achieves improved wound repair and muscle function assessment, carrying out a monitoring-guided safe and accurate wound repair.

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.

Hydrogel-based therapies for diabetic foot ulcers: recent developments and clinical implications

The diabetic foot ulcer is among the most serious diabetes-associated complications, with a long disease course considerably increasing the pain and economic burden of patients, leading to amputation and even death. High blood sugar is characteristic of diabetic foot ulcers, with insufficient blood supply, oxidative stress disorder, and high-risk bacterial infection posing great challenges for disease treatment. Advances in hydrogel dressings have shown potential for the management of diabetic foot ulcers involving multisystem lesions. This study comprehensively reviews the pathogenesis of diabetic foot ulcers and advances in hydrogel dressings in treating diabetic foot ulcers, providing innovative perspectives for assessing the nursing care requirements and associated clinical applications.

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.