Bone is a dynamic tissue with an extensive vascular network that provides the body necessary mechanical and structural support. Critical size bone defect repairing is still a major clinical challenge and requires bone grafts or bone substitutes. Bone tissue engineering is a growing research field that focuses on the production of scaffolds for implantation at bone defects. A variety of biomaterials and fabrication methods, including 3D printing, hav been introduced to fabricate specific bioactive scaffolds with controlled microarchitecture to repair bone defects. Today, the use of 3D printing methods to produce computer aided design tissue engineering scaffolds with the ability to repeat and proper control of the structure is expanding. 3D printing technology is known as a promising tool for fabricating high-precision scaffolds and creating biomimetic 3D structures with complex details. Therefore, in this study, polycaprolactone (PCL) scaffolds containing different amounts (0, 20, 35,50 and 65% wt.) of diopside nanoparticles were prepared by RoboCasting 3D printing method. In order to study the microstructure, elemental and phase analyses and also to study the functional groups, scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used, respectively. High purity diopside nanoparticles were synthesized by sol-gel method. Based on the results, surface roughness increased with increasing diopside amounts in printed nanocomposite scaffolds. On the other hand, the surface water contact angle was reduced from 91.81± 1.59 for PCL scaffold to 47.25± 2.86 for P-65% Dio scaffold, and the porosity was increased from 60.73% for PCL to71.96% for P-65%Dio. Also, according to the mechanical properties test, adding 50%wt. of diopside nanoparticles to the PCL scaffold increased the compressive strength (from 1 to 3.27 MPa) and the elastic modulus (from11.04 to 34.45MPa), and the 3D-printed P-50%Dio scaffold was selected as the optimal sample. The degradability of 3D-printed nanocomposite scaffolds was eva‎luated in PBS solution for 28days, and it was proved that increasing the amounts of diopside nanoparticles increased the degradability during this period. The formation of surface apatite layer on nanocomposite scaffolds was confirmed during 28days of immersion in simulated body fluid (SBF), and it was shown that with increasing diopside amounts in the nanocomposite, apatite deposits appeared with higher density on the surface. MTT assay confirmed non-toxicity of the printed scaffolds, and MG63 cell adhesion occurred to a greater extent on the surface of the printed P-50%Dio scaffold than on the PCL. Based on the results obtained in this study, the use of P-50%Dio nanocomposite scaffold made by RoboCasting 3D printing method is recommended for use in bone tissue engineering applications.

رحمت الله عمادي

علي پورسمر

مهدي احمديان، نرگس جوهري