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Scaffold creates a chance for bone growth and facilitates cell adhesion, growth and differentiation in orthopedic surgeries. Designing scaffold with adequate porous geometry and suitable compressive strength is debatable among biomaterial engineers and clinical orthopedic surgeons. Therefore, in this study we fabricate a novel porous hydroxyapatite-wollastonite reinforced with 0, 5, 10, and 15 wt% alumina nanoparticles (ALN: 40–80 nm) for bone substitute. In the current work, a porous cylindrical scaffold (6 mm × 10 mm) fabricated with space holder (SH) technique using sodium bicarbonate (NaHCO 3) as a porous agent. The porosity, compressive strength and the biological behavior of the porous samples were investigated using standard mechanical and biological testing. After making the specimen, scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis were performed to verify the accuracy of the nanomaterial's properties. The mechanical and biological analysis (swelling & water absorption) showed that the sample with 10 wt% alumina nanoparticles (ALN) had both proper compression strength vs. porosity percentage and bioactivity response. The molecular modeling for predicting the elastic modulus of bio-nanocomposite were performed and the results were close to the experimental values. The obtained result, indicated that compressive strength increased from 2.8 to 3.5 MPa with 49% to 61% porosity value. The sample with 10 wt% ALN and wollastonite showed clinical applications of these composites as a bone-substitute. Unlabelled Image • A novel porous scaffold creates a chance for bone growth and facilitates cell adhesion. • A novel porous hydroxyapatite-wollastonite reinforced with alumina nanoparticles for orthopedic bone substitute. • The samples showed a compressive strength with 3.5 MPa and 61% porosity value. • The space holder technique was applied using NaHCO 3. • The micromechanical model was utilized to predict the effect of porosity on elastic modulus of the specimen. [ABSTRACT FROM AUTHOR]

Background: One of the most common fractures in the skeleton happens in the femur. One of the important reasons for this fracture is because it is the longest bone in the body and osteoporosis affect this part a lot. The geometric complexity and anisotropy properties of this bone have received a lot of attention in the orthopedic field. Methods: In this research, a femur designed using 3D printing machine using the middle part of the hip made of polylactic acid–hydroxyapatite (PLA–HA) nanocomposite containing 0, 5, 10, 15, and 25 wt% of ceramic nanoparticle. Three different types of loadings, including centralized loading, full-scale, and partially loaded, were applied to the designed femur bone. The finite element analysis was used to analyze biomechanical components. Results: The results of the analysis showed that it is possible to use the porous scaffold model for replacement in the femur having proper strength and mechanical stability. Stress–strain analysis on femoral implant with biometric HA and PLA after modeling was performed using the finite element method under static conditions in Abaqus software. Conclusion: Three scaffold structures, i.e., mono-, hybrid, and zonal structures, that can be fabricated using current bioprinting techniques are also discussed with respect to scaffold design. [ABSTRACT FROM AUTHOR]