A low-swelling alginate hydrogel with antibacterial hemostatic and radical scavenging properties for open wound healing.

Development of a low-cost and biocompatible hydrogel dressing with antimicrobial, antioxidant, and low swelling properties is important for accelerating wound healing. Here, a multifunctional alginate hydrogel dressing was fabricated using the D-(+)-gluconic acidδ-lactone/CaCO3system. The addition of hyaluronic acid and tannic acid (TA) provides the alginate hydrogel with anti-reactive oxygen species (ROS), hemostatic, and pro-wound healing properties. Notably, soaking the alginate hydrogel in a poly-ϵ-lysine (EPL) aqueous solution enables the alginate hydrogel to be di-crosslinked with EPL through electrostatic interactions, forming a dense network resembling 'armor' on the surface. This simple one-step soaking strategy provides the alginate hydrogel with antibacterial and anti-swelling properties. Swelling tests demonstrated that the cross-sectional area of the fully swollen multifunctional alginate hydrogel was only 1.3 times its initial size, thus preventing excessive wound expansion caused by excessive swelling. After 5 h ofin vitrorelease, only 7% of TA was cumulatively released, indicating a distinctly slow-release behavior. Furthermore, as evidenced by the removal of 2,2-diphenyl-1-picrylhydrazyl free radicals, this integrated alginate hydrogel systems demonstrate a notable capacity to eliminate ROS. Full-thickness skin wound repair experiment and histological analysis of the healing site in mice demonstrate that the developed multifunctional alginate hydrogels have a prominent effect on extracellular matrix formation and promotion of wound closure. Overall, this study introduces a cost-effective and convenient multifunctional hydrogel dressing with high potential for clinical application in treating open wounds.

An ECM-mimicking assembled gelatin/hyaluronic acid hydrogel with antibacterial and radical scavenging functions for accelerating open wound healing.

A multifunctional hydrogel dressing with hemostatic, antibacterial, and reactive oxygen species (ROS)-removing properties is highly desirable for the clinical treatment of open wounds. Although many wound dressings have been prepared, the modification of polymers is often involved in the preparation process, and the uncertainty of biological safety and stability of modified polymers hinders the clinical application of products. In this study, inspired by the composition and crosslinking pattern of extracellular matrix (ECM), a deeply ECM-mimicking multifunctional hydrogel dressing is created. Tannic acid (TA) and poly-ϵ-lysine (EPL) are added into a gelatin/hyaluronic acid (Gel/HA) matrix, and a stable hydrogel is formed due to the formation of the triple helix bundles of gelatin and hydrogen bonds between polymers. The introduction of TA and EPL endows the ECM-mimicking hydrogel with stable rheological properties, as well as antibacterial and hemostatic functions. The as-produced hydrogels have suitable swelling ratio, enzyme degradability, and good biocompatibility. In addition, it also shows a significant ability to eliminate ROS, which is confirmed by the elimination of 2,2-diphenyl-1-picrylhydrazyl free radical. Full-thickness skin wound repair experiment and histological analysis of the healing site in mice demonstrate that the developed ECM-mimicking Gel/HA hydrogels have a prominent effect on ECM formation and promotion of wound closure. Taken together, these findings suggest that the multifunctional hydrogels deeply mimicking the ECM are promising candidates for the clinical treatment of open wounds.

OIC-A006-loaded true bone ceramic heals rabbit critical-sized segmental radial defect.

It has been reported that OIC-A006, an osteogenically inducible compound, is able to promote osteogenesis in vitro and in vivo. In this study, we used a rabbit critical-sized segmental radial defect model (CSD) (15 mm) to analyse the osteogenic activity of OIC-A006 in non-cell-seeded tissue engineering bone substitutes. The scaffold carrier was bovine sintered bone "true bone ceramic (TBC)". OIC-A006 was delivered by PLGA (D,L-lactide-co-glycolide acid) microspheres. Drug-free PLGA microspheres and rhBMP-2-loaded PLGA microspheres were used as negative and positive control groups, respectively. Three kinds of composite were fabricated by coupling TBC, type-I collagen and the corresponding microspheres. The animals were randomly divided into 4 groups: (1) Group A: defect only, (2) group B:TBC/Collagen/drug-free-microspheres, (3) group C:TBC/Collagen/ OIC-A006-microspheres, (4) group D: TBC/Collagen/rhBMP-2-microspheres. The samples were analysed by histology, X-ray,microcomputed tomography (micro-CT), and biomechanical analyses. The results showed that OIC-A006 promoted bone regeneration to a remarkable extent. It is suggested that the application of OIC-A006 might be a valuable method in bone tissue engineering for healing large segmental defects of long bones. However, the biomechanical strength was a little inferior to that of BMPs.