Silver@Prussian Blue Core-Satellite Nanostructures as Multimetal Ions Switch for Potent Zero-Background SERS Bioimaging-Guided Chronic Wound Healing

Enhanced Mechanical Strength and Sustained Drug Release in Carrier-Free Silver-Coordinated Anthraquinone Natural Antibacterial Anti-Inflammatory Hydrogel for Infectious Wound Healing

The persistent challenge of healing infectious wounds and the rise of bacterial resistance represent significant hurdles in contemporary medicine. In this study, based on the natural small molecule drug Rhein self-assembly to form hydrogels and coordinate assembly with silver ions (Ag+), a sustained-release carrier-free hydrogel with compact structure is constructed to promote the repair of bacterial-infected wounds. As a broad-spectrum antimicrobial agent, Ag+ can avoid the problem of bacterial resistance caused by the abuse of traditional antibiotics. In addition, due to the slow-release properties of Rhein hydrogel, continuous effective concentration of Ag+ at the wound site can be ensured. The assembly of Ag+ and Rhein makes the hydrogel system with enhanced mechanical stability. More importantly, it is found that Rhein effectively promotes skin tissue regeneration and wound healing by reprogramming M1 macrophages into M2 macrophages. Further mechanism studies show that Rhein realizes its powerful anti-inflammatory activity through NRF2/HO-1 activation and NF-κB inhibition. Thus, the hydrogel system combines the excellent antibacterial properties of Ag+ with the excellent anti-inflammatory and tissue regeneration ability of Rhein, providing a new strategy for wound management with dual roles.

Hollow Copper Sulfide Photothermal Nanodelivery Platform Boosts Angiogenesis of Diabetic Wound by Scavenging Reactive Oxygen Species

Sharply rising oxidative stress and ineffectual angiogenesis have imposed restrictions on diabetic wound healing. Here, a photothermal-responsive nanodelivery platform (HHC) was prepared by peroxidase (CAT)-loaded hollow copper sulfide dispersed in photocurable methacrylamide hyaluronan. The HHC could scavenge reactive oxygen species (ROS) and promote angiogenesis by photothermally driven CAT and Cu2+ release. Under near-infrared light irradiation, the HHC presented safe photothermal performance (<43 °C), efficient bacteriostatic ability against E. coli and S. aureus. It could rapidly release CAT into the external environment for decomposing H2O2 and oxygen generation to alleviate oxidative stress while promoting fibroblast migration and VEGF protein expression of endothelial cells by reducing intracellular ROS levels. The nanodelivery platform presented satisfactory therapeutic effects on murine diabetic wound healing by modulating tissue inflammation, promoting collagen deposition and increasing vascularization in the neodermis. This HHC provided a viable strategy for diabetic wound dressing design.

Facile strategy for gelatin-based hydrogel with multifunctionalities to remodel wound microenvironment and accelerate healing of acute and diabetic wounds

Chronic diabetic wounds represent the most common diabetes complication. Wound healing depends on scavenging reactive oxygen species (ROS), neovascularization, and controlling infection. A naturally derived gelatin-based hydrogel is biocompatible, biodegradable, does not promote inflammation, and can remove ROS, but strategies for developing a gelatin-based hydrogel currently require careful chemical modification of gelatin and time-consuming purification and post-crosslinking processing. Herein, a facile method of combining zirconium (Zr4+), gelatin, and quercetin (QCN) to generate an injectable gelatin-based hydrogel (QCN@Gel-Zr) for diabetic wound treatment was presented. Adding QCN improved the mechanical, injection, and adhesive performance of the Gel-Zr hydrogel and conferred antibacterial and free radical-scavenging abilities. These properties induced cellular proliferation and migration, protection against oxidative stress, and reduction in inflammatory expression. In vivo models of acute and chronic diabetic skin wounds were used to demonstrate biocompatibility and the ability of the gelatin hydrogels to promote wound healing. The histological analysis showed that the QCN@Gel-Zr hydrogel promoted angiogenesis, collagen deposition, and hair follicle regeneration with no detectable cytotoxicity. This study demonstrates the preparation of gelatin-based hydrogel with various flexible functions to address the complex biological requirements of diabetic wound repair.