Poly(ε-caprolactone), zinc oxide nanoparticles, and chitosan scaffold as skin substitutes: mechanical strength and cell viability analysis

Human skin is a multilayered nanocomposite that serves as a protective barrier against external factors. Utilizing multilayered skin substitutes that mimic the structure of human skin can considerably enhance the wound-healing process. In this study, different amounts of zinc oxide nanoparticles (n-ZnO) were added to a poly(ε-caprolactone) (PCL) solution, which was poured into molds containing NaCl porogens of two particle sizes. A salt leaching and solvent casting procedure was used to construct PCL/n-ZnO scaffolds with a bilayer structure. These scaffolds were analyzed to determine their phase structure, chemical functional groups, mechanical properties, biodegradation behavior, and cell viability and adhesion characteristics. The results indicated that none of the scaffolds had degraded considerably or lost much mass after 30 days of immersion in phosphate-buffered saline. Compressive mechanical analysis revealed that the PCL/15n-ZnO/CS scaffold exhibited the highest compressive strength and modulus, approximately 2.1 and 3.5 MPa, respectively. However, after 1 week of cell culture, cell viability was adequate for none of the synthesized scaffolds. In addition, the biocompatibility of the scaffolds decreased with increasing n-ZnO amount. Taken together, these findings indicate that although PCL/n-ZnO scaffolds exhibit promising mechanical properties, the concentration of ZnO must be optimized to ensure the biocompatibility of the scaffolds without compromising their strength. Future studies should focus on balancing the mechanical performance and cellular survival of scaffolds by incorporating various nanoparticle concentrations or surface changes and improving the design of scaffolds for more effective biodegradation and tissue regeneration.