Injectable hydrogels, of which the cover area and volume can be flexibly adjusted according to the shape and depth of the wound, are considered to be an ideal material for wound dressing. Konjac glucomannan (KGM) is a natural polysaccharide with immunomodulatory capability, while γ-polyglutamic acid (γ-PGA) is a single chain polyamino acid with moisturizing, water-retention and antibacterial properties. This work intended to combine the advantages of the two materials to prepare an injectable hydrogel (P-OK) by mixing the adipic acid dihydrazide (ADH) modified γ-PGA with oxidized KGM. The chemical structures, the physical and chemical properties, and the biological properties of the P-OK hydrogel were evaluated. The optimal conditions to form the P-OK hydrogel were fixed, and the cytotoxicity, qPCR, antibacterial and animal experiments were performed. Results showed that the P-OK hydrogel had a fast gelation time, good water-retention rate, little cytotoxicity, good immunomodulating and antibacterial capabilities, and could shorten the healing period in the rat full-thickness defect model, which makes it a potential candidate for wound repair dressing.
Qiao Zhang,Jinlin Chen,Tianyu Zhang,Dan Liu,Xirui Long,Jiehua Li,Lu Jiang,Yanchao Wang,Hong Tan
In the field of oral and maxillofacial surgery, extensive oral soft-tissue injuries occur repeatedly in clinical practice; however, effective restorative materials are lacking. In this study, a biodegradable waterborne polyurethane patch featuring a mucosa bionic bilayer structure is presented. This patch consists of a porous scaffold layer that faces the lesion, incorporating a polydopamine coating to achieve sustained release of epidermal growth factors (EGFs) for mucosal defect reconstruction. Additionally, there is a dense barrier layer toward the oral cavity loaded with silver nanoparticles, which prevents bacteria from entering the wound and simultaneously acts as a physical barrier. This patch can sustainably release EGF in vitro for 2 weeks, thereby facilitating the proliferation and migration of HaCaT and L929 cells, while effectively killing common oral cavity bacteria. In a rabbit buccal mucosal full-thickness defect model, the patch demonstrates better efficacy than the clinical benchmark, decellularized extracellular matrix (dECM). It effectively reduces wound inflammation and significantly upregulates gene expression associated with epithelialization by activating the EGF/epidermal growth factor receptor (EGFR) pathway. These mechanisms promote the proliferation, differentiation, and migration of epithelial/keratinocyte cells, ultimately expediting mucosal defect healing and wound closure.
Limited self-renewal potency of cartilage impedes the repair and regeneration at the site of damage. Investigating small-molecule compounds to boost chondrogenesis has yielded the dawn. However, the durability and targeting of current drug delivery and the adaptive integration for cartilage defects are not addressed. Herein, we fabricated a dynamic hydrogel based on the coordination between metal ions and collagen and then supramolecularly enveloped with a chondro-inductive factor kartogenin (KGN) via cyclodextrin (CD). The self-recovery and injectability of dynamic hydrogel enabled minimally invasive and precise treatment of cartilage injury assisted by continuous KGN administration. The hydrogel could significantly promote the expression of cartilage matrix components (type II collagen and aggrecan) in articular chondrocytes without affecting cell proliferation or migration in vitro . Mechanistically, the protective effects depended on enhancing chondrocyte mitochondrial function and intracellular antioxidant properties. In situ hydrogel injection strengthened cartilage regenerative potential and facilitated the reconstruction of subchondral bone following full-thickness defects in vivo . This study revealed that the dynamic chondrogenic hydrogel could benefit cartilage repair via mitochondrial reinforcement, acting as a novel therapeutic strategy for refractory cartilage damage.
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