Fabrication and evaluation of auto-stripped tri-layer wound dressing for extensive burn injury

In the study, we are going to develop a tri-layer membrane as the artificial skin for extensive burn injury. The first layer is a three-dimensional tri-copolymer sponge of gelatin/hyaluronan/chodroitin-6-sulfate with 70% in porosity and 20-100 μm in pore size. The layer is constructed as a dermis analogous layer to stimulate capillaries penetration, to promote dermal fibroblast migration and to induce the secretion of extra-cellular matrix, which provides a better physiological environment for burn patient recovery. The second layer is as so called auto-stripped layer composed by poly-N-isopropyacrylamide (PNIPAAm). The layer will be automatically peeled off from the tri-copolymer layer once the wound site closed and recovered. The third layer is composed by polypropylene (PP) non-woven fabric, which provides an open structure for exudates drainage out that will reduce the risk of second infection. The tri-layer wound dressing has been successfully prepared by subsequently high-energy plasma treatment, γ-ray irradiation, UV light exposure, and lyophilized process. From the results of MTT, IL-8, IL-1α, IL-6, and TNF-α measurement, the developed material will not induce tissue inflammatory or immune response. The dermal fibroblasts showed initial contact with the material surface through the radial extension of filopodia followed by cytoplasmic webbing that could be examined by SEM. Dermal fibroblasts subsequently flattened for further proliferation and extra-cellular matrix secretion. Dermal analog layer provides a three-dimensional architecture for normal dermis regeneration. The layer can be completely biodegraded within 4 weeks post-operation. After served as a scaffold for the ingrowth of self-fibroblasts, a normal dermis like layer will be regenerated. The dressing will fall off automatically without any damage once the wound site healed completely.