Microstructure and biocompatibility of TPMS-based scaffolds

In our study, the cancellous-bone like and cortical-bone like TPMS-based Gyroid porous Ni@Al2O3/CoCrMo scaffolds with homogenous porosity of 60% (G60), 75% (G75) and radially graded porosity of 50%-80% (F70) were fabricated by Selective Laser Melting (SLM) process. The effects of porosity on the compressive behavior and elastic modulus were investigated, where the F70 scaffold with radially graded porosity performed the best match with healthy adults. By measuring the release of cobalt and chromium ions in the extracting liquid and cytotoxicity of porous scaffolds, both G75 and F70 scaffolds presented lower ion release rate and excellent biocompatibility. After implantation in rabbits for 8 weeks, the F70 scaffold demonstrated approximately 90% bone ingrowth with enhanced osteointegration. The outstanding biological properties of SLM-processed TPMS porous Ni@Al2O3/CoCrMo scaffolds have made it suitable for the metallic orthopedic implants in the field of hip joint replacement.Therefore, these uploaded figures come from the results of above study.Figure 1 shows the TPMS structures with different porosityFigure 2 shows Schematic illustration of (A) in vitro and (B) in vivo experimental procedureFigure 3 shows SEM image of the G60 (a,a1), F70 (b,b1) and G75 (c,c1) scaffoldsFigure 4 shows Mechanical property of G60, F70 and G75 scaffolds: The engineering stress-strain curve of cancellous-like bone scaffolds (a1), and cortical-like bone scaffolds (a2); The yield strength and elastic modulus of cancellous-like bone scaffolds (b1), and cortical-like bone scaffolds (b2) Figure 5 shows Ions concentrations of extracting liquid over 7, 14, and 28 days (A), and OD values of cell suspension for 2, 4, and 6 days (B)Figure 6 shows Cell viability cultured in different extracting liquid for 2, 4, and 6 daysFigure 7 shows Morphology of MC3T3-E1 cells and Alcian Blue-stained cells after being cultured in 6-day extracting liquid for 2 daysFigure 8 shows Morphology and EDS elemental mapping of TPMS-G scaffolds immersed in PBS solution for 1-3 weeksFigure 9 shows In vivo assessment of bone regeneration in rabbits: (A) Gross images of bone defect model and implantation surgery, (B) Gross images of bone healing after 8 weeks of implantation, (C) X-ray image after 8 weeks of implantation, with the (c1) F70 and (c2) G75 implants in the yellow circleFigure 10 shows H&E-stained histological images of hard tissue sections and implant area proportion histograms for F70 and G75 implants in rabbit femursFigure 11 shows Morphology and element mappings of (a) F70 and (b) G75 implants after 8-week implantationFigure 12 shows H&E-stained sections of the heart, lung, liver, spleen, and kidney in rabbits after 8-weeks post-implantation