Dextran-Allyl Isocyanate-Ethylamine Hydrogel for Treating Third-Degree Dermal Burn Wounds
Song, Hyun Ho
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Third-degree burn wound is characterized by the full-thickness injury of the skin, including both the epidermal and the dermal layer. These wounds do not heal spontaneously and require excision of the necrotic tissue. Currently, split-thickness skin autografts are commonly used for wound closure, but these can leave thick scars and distorted contractures, which is unfavorable both functionally and aesthetically. In previous works, we have developed a dextran-based hydrogel that is chemically modified with allyl isocycanate and bromoethylamine (Dex-AE) that was tailored to enhance biocompatibility and host-cell infiltration in vivo. Polyethyl glycol diacrylate (PEGDA) was added to the hydrogel mix to strengthen the mechanical properties of the hydrogel without compromising the crosslinking density. The therapeutic effect of the gel was first confirmed by the murine in vivo burn wound model, where the hydrogel-treated wounds healed completely with regenerated skin appendages by week 8. We then aimed to translate this model into a porcine model because of its structural and biological similarities to the human skin. We first optimized our protocol to create third-degree burn wounds by using different contact temperature and duration. We used this established protocol to conduct our hydrogel treatment studies, where the burned necrotic wounds were first excised and then replaced with our Dex-AE/PEGDA hydrogels. The hydrogel degraded within 5 days after the implantation with higher cell infiltration compared to the control group. In order to analyze the healing process, we have conducted histological assays as well as blood flow analysis with a speckle contrast imager. Our preliminary data showed signs of higher blood support in the hydrogel-treated wounds that may have contributed to the better epithelial healing that we observed in treated group. We also observed higher cellular infiltration in the areas of the hydrogel-treated wounds compared to the untreated wounds, confirmed by the hematoxylin and eosin staining of the samples at day 2. With additional surgical adjustments, the bioactive hydrogel shows potential for delivering appropriate treatment for third-degree burn wound healing.