Abstract Skin tissue, as the largest and one of the most important organs of the human body, is composed of three main layers: epidermis, dermis and hypodermis. The dermis layer is the most damaged, and the skin is currently being removed from other parts of the body to repair it, which in turn causes defects in those areas. For this reason, the use of biological materials as cell support to regenerate damaged parts of this tissue is very important in tissue engineering. In the present study, a three-layer scaffold with porosity gradient changes was constructed to model living skin tissue and accelerate wound healing. Porous polycaprolactone / zinc oxide nanoparticle nanocomposites were fabricated with zero, 5, 10 and 15% by weight of zinc oxide nanoparticles in two layers by solvent casting / salt washing method. The third layer of chitosan was added to the other layer as a membrane with the help of sodium hydroxide crosslinking agent. The fuzzy structure, chemical functional group and morphology of the constructed scaffolds were examined using X-ray diffraction pattern (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. To eva‎luate the mechanical properties, the constructed scaffolds were tested for compressive strength. To eva‎luate the extent of degradation in the biological environment, the scaffolds were immersed in saline buffer phosphate solution for 30 days and their weight loss was calculated every 5 days. Ambient pH changes were also measured every two days. The biocompatibility of the constructed scaffolds was also eva‎luated using the Cytotoxicity Assay (MTT) of L929 fibroblast cells. The degree of cell adhesion of these cells on the constructed scaffolds was also eva‎luated by scanning electron microscopy images. The results showed that the porosity of the three-layer scaffolds made changes gradiently. Morphological consistency and compressive strength of scaffolds with 5% by weight of zinc oxide nanoparticles in which crosslinking agent was used to add chitosan membrane were significantly higher than samples without crosslinking agent. Also, after 30 days, all scaffolds made with zinc oxide nanoparticles did not lose any weight before and after the crosslinking agent. In addition, zero and 5% by weight scaffolds of zinc oxide nanoparticles showed higher viability after crosslinking agent, after 3 and 7 days of cell culture. All scaffolds showed good cell adhesion before cross-linking with sodium hydroxide, but after cross-linking with sodium hydroxide, scaffolds containing oxide nanoparticles showed excellent cell adhesion.

نرگس جوهري