abstract The increasing demand for advanced materials in biomedical applications has driven extensive research to develop composites that can meet specific mechanical and biological requirements. Traditional materials are often in capable in providing the necessary combination of properties required for medical applications for example in complex: bone tissue engineering. This has led to the discovery of composite materials that can be considered to achieve the desired properties by combining different micro and nano materials. The development of a composite material (polycaprolactone / high entropy oxide / tricalcium phosphate) has a significant potential for progress in the field of bone tissue engineering. The use of 3D printing technology further increases the potential of this composite by making it possible to manufacture customized implants and scaffolds with complex geometries and accurate distribution of materials. The purpose of this research is to construct and eva‎luate a nanocomposite scaffold (polycaprolactone / high entropy oxide / tricalcium phosphate) using the melt deposition method and using a 3D printer. Tricalcium phosphate and polycaprolactone have favorable bioactivity and biodegradability properties, but adding tricalcium phosphate to polycaprolactone reduces the compressive strength, so to improve the compressive strength, high entropy oxide was added to the composition, which generally caused the increases in compressive strength. In this study, high entropy oxide nano powder was doped with strontium to improve biological properties. A composite scaffold with a structure with 30% porosity was made and the mechanical properties were investigated by compresspn test. It was found that the scaffold with weight percentages of 70% polycaprolactone, 20% tricalcium phosphate and 10% high entropy oxide with strontium has the best compression strength between the other samples and was selected for further tests. In the non-toxicity test, the scaffold was confirmed to be non-toxic. In the antibacterial test, the result of dopied strontium to high entropy nano powder is quite clear. it was obvions at the doping of strontium to the powder has antibacterial properties. Finally, the successful manufacturing and eva‎luation of this composite material can lead to significant improvements in the treatment of bone defects and injuries and provide more effective and reliable solutions to the patients. In addition, this research contributes to the broader field of composite materials and provides insights and methods that can be applied to the development of other advanced materials for various biomedical applications.

تقي اصفهاني

محمد خدائي