Photothermal-enhanced in situ supramolecular hydrogel promotes bacteria-infected wound healing in diabetes

Dual oxygen supply system of carbon dot-loaded microbubbles with acoustic cavitation for enhanced sonodynamic therapy in diabetic wound healing

Diabetic wounds present significant treatment challenges due to their complex microenvironment, marked by persistent inflammation from bacterial infections, hypoxia caused by diabetic microangiopathy, and biofilm colonization. Sonodynamic therapy (SDT) offers potential for treating such wounds by targeting deep tissues with antibacterial effects, but its efficacy is limited by hypoxic conditions and biofilm barriers. To overcome these obstacles, we developed a novel approach using oxygen-carrying microbubbles loaded with Mn2+-doped carbon dots (MnCDs@O2MBs) to enhance SDT and disrupt biofilms. Through precursor screening and design, MnCDs are engineered to exhibit tailored properties of sonodynamic activity and enzyme-like catalytic capabilities. This system provides a dual oxygen supply for amplifying the SDT effects: MnCDs, serving as a sonosensitizer, also chemically convert excess H2O2 at infection sites into oxygen, while the O2MBs physically release oxygen through ultrasound-induced cavitation. The cavitation effect also disrupts biofilms, improving the delivery of sonosensitizers and boosting SDT efficacy. In a diabetic wound model, this strategy downregulated TLR, NF-κB, and TNF inflammatory pathways, reduced pro-inflammatory factor secretion, promoted angiogenesis, and accelerated wound healing, thereby acting as a promising treatment approach for diabetic wound healing.

cGAS-mediated antibacterial immunotherapy against tuberculosis by macrophage-targeted manganese dioxide nanoagonist

Tuberculosis (TB), induced by Mycobacterium tuberculosis (Mtb) infection, remains one of the top killers among infectious diseases. The pathogenesis hallmarks for TB are complex immune escape mechanisms of Mtb and low targeting effects of anti-TB drugs. cGAS signaling, which is responsible for triggering host antibacterial immunity against Mtb infection, has shown potentials to serve as targets for anti-TB immunotherapy. As cGAS agonist manganese ions (Mn2+) can activate cGAS-mediated autophagy to inhibit intracellular Mtb in macrophages, we constructed a functional nanoagonist targeting cGAS signaling based on manganese dioxide nanoparticles, naming Tuf-Rif@HA-MnO2 NPs, for synergistic macrophage-targeted drug delivery and anti-TB immuno-therapeutics. Tuf-Rif@HA-MnO2 NPs can actively target macrophages for rifampicin delivery and react with intracellular glutathione (GSH) to release Mn2+ for cGAS-STING signaling activation, which further promote autophagy and antibacterial M1 polarization of Mtb infected macrophages to achieve synergistic intracellular Mtb clearance. Furthermore, Tuf-Rif@HA-MnO2 NPs can potentiate dendritic cell maturation, CD4+ Th1 cell and CD8+ cytotoxic T cell activation in vivo, which collectively attribute to reduced Mtb burdens and alleviated tissue inflammations in lung of Mtb-infected mice without systemic toxicity. This macrophage targeted drug delivery nanoagonist system is expected to develop rational immunotherapy strategy targeting cGAS signaling against TB and drug-resistant TB. STATEMENT OF SIGNIFICANCE: cGAS-mediated autophagy plays a critical role in Mtb clearance in macrophages. Tuf-Rif@HA-MnO2 NPs specifically deliver rifampicin into macrophage for Mtb clearance. Tuf-Rif@HA-MnO2 NPs activate cGAS-mediated macrophage autophagy for Mtb clearance. Tuf-Rif@HA-MnO2 NPs synergize cGAS-mediated immunotherapy with targeted drug delivery for more effective anti-TB treatment.

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

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

Smart hydrogels for rapid wound repair: Chitosan-PVP matrices empowered by bimetallic MOF nanocages

In wound treatment, sustainable and effective dressings are crucial for rapid healing without scarring. Antimicrobial transparent hydrogel dressings were fabricated by grafting chitosan with polyvinyl pyrrolidone and impregnating it with zinc or zinc-silver metal-organic framework nanocages (30-50 nm). Characterization confirmed the hydrogels' excellent physical and chemical integrity. Comprehensive antibacterial, antifungal, and ion-release evaluations validated their efficacy, demonstrating remarkable results. These dressings also promoted a moisture-balanced environment ideal for wound healing. Comprehensive evaluations of these hydrogel dressings' antibacterial, antifungal, and ion-release properties confirmed their efficacy, demonstrating remarkable results. The dressings also promoted a moisture-balanced environment optimal for wound healing. Cytotoxicity tests on skin cells indicated that the hydrogels were safe and enhanced cell proliferation. Notably, CS/PVP hydrogels with bimetallic nanocages (CS/PVP4) achieved up to 69 % healing within 7 days. This rapid healing occurred due to the reduction of inflammation and IL-1 content in the dermis; the downregulation of MMP9 halted the breakdown of the extracellular matrix (ECM); the upregulation of TGF accelerated cell growth and raised the levels of collagen 1 and -SMA in the ECM. These findings suggest that the developed hydrogel dressings will provide sustainable wound healing, thereby increasing patient satisfaction.

Modular Engineering of Lysostaphin with Significantly Improved Stability and Bioavailability for Treating MRSA Infections

Methicillin-resistant Staphylococcus aureus (MRSA) is a refractory pneumonia-causing pathogen due to the antibiotic resistance and the characteristics of persisting inside its host cell. Lysostaphin is a typical bacteriolytic enzyme for degrading bacterial cell walls via hydrolysis of pentaglycine cross-links, showing potential to combat multidrug-resistant bacteria. However, there are still grand challenges for native lysostaphin because of its poor shelf stability and limited bioavailability. To tackle these limitations, a modular assembly strategy is proposed to actively engineer the native lysostaphin, involving nanoassembly preparation via fusing with lysine-rich polypeptide. The engineered lysine component significantly improves the membrane-penetration capability of lysostaphin, greatly increasing its intracellular antibacterial activity by 12-fold compared to wild-type lysostaphin. Notably, the half-life of the nanoassembled lysostaphin is approximately 13 times longer than that of its native counterpart, greatly outperforming other studies. Most importantly, the shelf stability of our engineered lysostaphin is significantly improved, retaining over 99.9% of antibacterial activity after 12 weeks at room temperature. This modular assembly strategy successfully enhances the overall performance of lysostaphin, offering great promise for a platform technique to refine enzymatic material for widespread clinical demands.

Biosynthesis of Lysosomally Escaped Apoptotic Bodies Inhibits Inflammasome Synthesis in Macrophages

Hyperglycemia and bacterial colonization in diabetic wounds aberrantly activate Nod-like receptor protein 3 (NLRP3) in macrophages, resulting in extensive inflammatory infiltration and impaired wound healing. Targeted suppression of the NLRP3 inflammasome shows promise in reducing macrophage inflammatory disruptions. However, challenges such as drug off-target effects and degradation via lysosomal capture remain during treatment. In this study, engineered apoptotic bodies (BHB-dABs) derived from adipose stem cells loaded with β-hydroxybutyric acid (BHB) were synthesized via biosynthesis. These vesicles target M1-type macrophages, which highly express the folic acid receptor in the inflammatory microenvironment, and facilitate lysosomal escape through 1,2-distearoyl-sn-propyltriyl-3-phosphatidylethanolamine-polyethylene glycol functionalization, which may enhance the efficacy of NLRP3 inhibition for managing diabetic wounds. In vitro studies demonstrated the biocompatibility of BHB-dABs, their selective targeting of M1-type macrophages, and their ability to release BHB within the inflammatory microenvironment via folic acid and folic acid receptor signaling. These nanovesicles exhibited lysosomal escape, anti-inflammatory, mitochondrial protection, and endothelial cell vascularization properties. In vivo experiments demonstrated that BHB-dABs enhance the recovery of diabetic wound inflammation and angiogenesis, accelerating wound healing. These functionalized apoptotic bodies efficiently deliver NLRP3 inflammasome inhibitors using a dual strategy of targeting macrophages and promoting lysosomal escape. This approach represents a novel therapeutic strategy for effectively treating chronic diabetic wounds.

The interplay of skin architecture and cellular dynamics in wound healing: Insights and innovations in care strategies

Wound healing involves complex interactions among skin layers: the epidermis, which epithelializes to cover wounds; the dermis, which supports granulation tissue and collagen production; and the hypodermis, which protects overall skin structure. Key factors include neutrophils, activated by platelet degranulation and cytokines, and fibroblasts, which aid in collagen production during proliferation. The healing process encompasses inflammation, proliferation, and remodeling, with angiogenesis, fibroplasia, and re-epithelialization crucial for wound closure. Angiogenesis is characterized by the creation of collateral veins, the proliferation of endothelial cells, and the recruitment of perivascular cells. Collagen is produced by fibroblasts in granulation tissue, aiding in the contraction of wounds. The immunological response is impacted by T cells and cytokines. External topical application of various formulations and dressings expedites healing and controls microbial contamination. Polymeric materials, both natural and synthetic, and advanced dressings enhance healing by providing biodegradability, biocompatibility, and infection control, thus addressing tissue regeneration challenges. Numerous dressings promote healing, including films, hydrocolloids, hydrogels, foams, alginates, and tissue-engineered substitutes. Wound dressings are treated with growth factors, particularly PDGF, and antibacterial drugs to prevent infection. The challenges of tissue regeneration and infection control are evolving along with the field of wound care.

Liraglutide Promotes Diabetic Wound Healing via Myo1c/Dock5

Non-healing diabetic wounds and ulcer complications, with persistent cell dysfunction and obstructed cellular processes, are leading causes of disability and death in patients with diabetes. Currently, there is a lack of guideline-recommended hypoglycemic drugs in clinical practice, likely due to limited research and unclear mechanisms. In this study, it is demonstrated that liraglutide significantly accelerates wound closure in diabetic mouse models (db/db mice and streptozotocin-induced mice) by improving re-epithelialization, collagen deposition, and extracellular matrix remodeling, and enhancing the proliferation, migration, and adhesion functions of keratinocytes. However, these effects of improved healing by liraglutide are abrogated in dedicator of cytokinesis 5 (Dock5) keratinocyte-specific knockout mice. Mechanistically, liraglutide induces cellular function through stabilization of unconventional myosin 1c (Myo1c). Liraglutide directly binds to Myo1c at arginine 93, enhancing the Myo1c/Dock5 interaction by targeting Dock5 promoter and thus promoting the proliferation, migration, and adhesion of keratinocytes. Therefore, this study provides insights into liraglutide biology and suggests it may be an effective treatment for diabetic patients with wound-healing pathologies.

Nanomotor-hydrogel Delivery System with Enhanced Antibacterial Performance for Wound Treatment

In this study, we present a novel system consisting of nanomotors and a hydrogel. Calcium carbonate nanomotors are prepared using layer-by-layer self-assembly technology with calcium carbonate nanoparticles as the core and catalase (CAT) and polydopamine (PDA) as the shell. Calcium carbonate nanomotors were loaded into a Schiff base hydrogel to synthesize the CaCO3@NM-hydrogel system. A nanomotor is a device that works on the nanoscale to convert some form of energy to mechanical energy. The motion speed of the system in 5.0 mM H2O2 aqueous solution under near-infrared light (NIR) irradiation with a power density of 1.8 W/cm2 is 13.6 μm/s. The addition of CaCO3@NM further promotes gelation and improves the mechanical properties. The energy storage modulus increases to 4.0 × 103 Pa, which is 50 times higher. Schiff base hydrogels form dynamic reversible chemical bonds due to inter- and intramolecular hydrogen bonding. They also have good self-healing properties, as observed by measuring the energy storage modulus versus the loss modulus at 1 versus 10 kHz. The results show that the system significantly inhibited the growth of both Gram-positive bacteria, Staphylococcus aureus, and Gram-negative bacteria, Escherichia coli, after 48 h, with an inhibition rate of nearly 95%. These findings provide a basis for further research and potential applications of the system in wound dressings.

A hydrogel based on Fe(II)-GMP demonstrates tunable emission, self-healing mechanical strength and Fenton chemistry-mediated notable antibacterial properties

Supramolecular hydrogels serve as an excellent platform to enable in situ reactive oxygen species (ROS) generation while maintaining controlled localized conditions, thereby mitigating cytotoxicity. Herein, we demonstrate hydrogel formation using guanosine-5'-monophosphate (GMP) with tetra(4-carboxylphenyl) ethylene (1) to exhibit aggregation-induced emission (AIE) and tunable mechanical strength in the presence of divalent metal ions such as Ca2+, Mg2+, and Fe2+. The addition of divalent metal ions leads to structural transformation in the metallogels (M-1GMP). Furthermore, the incorporation of Fe2+ ions into the hydrogel (Fe-1GMP) promotes the Fenton reaction that could be upregulated upon adding ascorbic acid (AA), demonstrating antibacterial efficacy via ROS generation. In vitro studies on AA-loaded Fe-1GMP demonstrate excellent bacterial killing efficacy against E. coli, S. aureus and vancomycin-resistant enterococci (VRE) strains. Finally, in vivo studies involving topical administration of Fe-1GMP to Balb/c mice with skin infections further suggest the potential antibacterial efficacy of the hydrogel. Taken together, the hydrogel with its unique combination of mechanical tunability, ROS generation capability and antibacterial efficacy can be used for biomedical applications, particularly in wound healing and infection control.