Abstract One of the new methods for the repair and reconstruction of bone tissue is the science of bone tissue engineering, the purpose of which is to build engineered scaffolds for the natural healing of tissue at the defect site, and among the methods of making bone scaffolds, the 3D printing is known as a promising tool due to its controllability for repairing defects, its 3D design with the shape and size of bone defects, and also being less expensive than other methods. Oxide with high entropy (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 has recently attracted a lot of attention from researchers because of its good mechanical properties and the combination of biocompatible elements. High entropy oxides have favorable chemical and physical stability properties as well as antimicrobial and antibacterial properties. The purpose of this research is to make polycaprolactone scaffolds containing high entropy oxide (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 for the treatment of damaged bone tissues in order to reduce treatment costs and not need complementary treatments. First, nanoparticles were examined by mechanical activation method, synthesis and properties by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). Nanocomposite scaffolds with a porous network structure with weight percentages of 20, 10, 0 and 35 were made by 3D printing method (melt deposition FDM). Based on the results of the mechanical properties test, adding 20% by weight of nanoparticles to the polycaprolactone scaffold increased the compressive strength compared to the pure polycaprolactone scaffold (from 1.3 to 13 MPa). which was chosen as the optimal sample in this research. The degradability of printed scaffolds containing 20% by weight of nanoparticles compared to pure polycaprolactone scaffold was eva‎luated for 28 days of immersion in biphosphate saline solution and it was proved that the addition of nanoparticles did not affect the degradability rate. According to the porous morphology of the scaffolds containing 20% by weight of nanoparticles compared to the pure polycaprolactone scaffold, the bioactivity and formation of hydroxyapatite, as well as the cell adhesion of MG63, have increased in laboratory conditions. Based on the MTT test, the non-toxicity of two groups of scaffolds containing 20% by weight of nanoparticles was observed. Based on the results obtained in this study, the use of polycaprolactone nanocomposite scaffold containing 20% by weight of nanoparticles (Mg0.2Ti0.2Zn0.2Cu0.2Fe0.2)3O4 made by 3D printing method for use in bone tissue engineering It is suggested.

تقي اصفهاني

محمد خدائي