Reviewed by Danielle Ellis, B.Sc.Sep 4 2024
Professor Hongbo Zhang of Åbo Akademi University in Finland, together with colleagues, presented a self-healing hydrogel dressing based on structural color microspheres for wound care in a study that was published in Nano-Micro Letter.
Image Credit: Nano-Micro Letters (2024). DOI: 10.1007/s40820-024-01422-4
Patients with chronic diabetes wounds are common and difficult to heal, posing a substantial medical problem. The creation of multifunctional hydrogel dressings with well-designed morphology and structure can improve their flexibility and efficacy in wound care.
These microspheres consist of an inverse opal framework with photothermal responsiveness, methacrylate hyaluronic acid, methacrylate silk fibroin, and black phosphorus quantum dots (BPQDs), which are then embedded in dynamic hydrogels.
The dynamic hydrogel filler is created via the Knoevenagel condensation process of cyanoacetate and benzaldehyde-functionalized dextran (DEX-CA and DEX-BA). Notably, the composite microspheres may be freely applied and stick to one another during near-infrared irradiation by making use of the BPQD-mediated photothermal effect and the dynamic hydrogel’s thermoreversible stiffness change.
Furthermore, the microspheres contain both melittin and vascular endothelial growth factor, and their release behavior can be controlled using the same technique. Furthermore, the drug release method can be successfully tracked via visible color changes. This microsphere technology is perfect for the regulated release of drugs and effective wound treatment.
Zhang and colleagues assessed the effectiveness of composite microspheres (CMPs) in vivo wound healing using a full-thickness chronic diabetic wound infection model. The diabetes model was created using intraperitoneal injections of streptozotocin (STZ) in Sprague-Dawley (SD) rats.
Image Credit: Annabell Gsoedl/Shutterstock.com
After their blood glucose levels stabilized, the rats’ dorsal region was lacerated with circular, full-thickness skin lesions. Then, different treatments were given to distinct rat groups to evaluate the efficacy of CMPs in accelerating wound healing.
The group treated with the dual-drug-loaded CMPs coupled with near-infrared (NIR) irradiation had improved wound healing outcomes, considerably surpassing other groups, according to statistical analysis of wound closure areas and regenerated epithelial thickness. These findings imply that a major factor in improving wound healing is the synergistic effects of NIR-controlled irradiation and the intelligent response of CMPs.
Bacterial infection is a crucial factor in the delayed healing process in chronic wounds. The study team used Masson's trichrome staining to assess collagen deposition at the wound site. Collagen organization and density were more noticeable, and collagen formation was higher in the drug-loaded CMPs group, indicating that the CMPs might induce extracellular matrix deposition.
In addition, neovascularization is important for wound healing. To study the effect of VEGF (vascular endothelial growth factor) on wound healing, CD31 immunofluorescence labeling was used to identify newly created blood vessels. Fluorescence pictures indicated less CD31-positive regions in the control group, whereas the CMPs@AMP&VEGF + NIR group had the greatest CD31 expression.
Journal Reference:
Wang, L., et. al. (2024) Self-Healing Dynamic Hydrogel Microparticles with Structural Color for Wound Management. Nano-Micro Letter. doi.org/10.1007/s40820-024-01422-4