The main aim of this paper is to achieve the suitable SA-GEL (sodium alginate and gelatin) porous cartilage scaffold by 3D printing technology with optimal prediction parameters. Firstly, the characteristics of SA-GEL were analyzed, the influence of calcium chloride on the gel was explored, and the optimal cross-linking concentration and gelation temperature were determined. Secondly, a prediction model of the extrusion line width of SA-GEL was established, in which the printing pressure, the moving speed of the needle and the fiber interval were the important parameters affecting the printing performance of the SA-GEL composite material. Thirdly, the SA-GEL composite scaffolds were printed on the Bio-plotter platform, the C5.18 chondrocytes cells were cultured in the SA-GEL biomaterial scaffold, and the results show that the cells could survive well. These results show that, under the control of the printing parameters pressure 1.8 bar, moving speed 10.7 mm/s and the internal structure parameters of the scaffold is 0/45-1.2 (Printing interval: 1.2 mm, angle value: 45 degree), SA-GEL scaffold printing results can be obtained which have good mechanical properties and biocompatibility.

To solve the mismatch between the comprehensive mechanical properties of the spinal fusion cage and body, a fusion cage inner hole design method based on controllable TPMS-P to characterize the inner hole structure is proposed to solve the related problems. Firstly, the method of TPMS-P parameterization was used to construct the bionic porous structure model, which was designed as the linear gradual internal porous structure model. Then, we optimized the topology of the obtained porous structure implants to achieve precise control of the overall comprehensive mechanical properties of the fusion cage structure and obtain an optimized model that matched the mechanical properties of the fusion cage. To verify whether the method met the requirements, its simulation model was established. The porous structure was fabricated by selective laser processing, and its properties were tested and analyzed. The results show that its yield strength is 79.83 MPa, which match well with spinal bone tissue.

Bone defects caused by bone diseases and bone trauma need to be implanted or replaced by surgery. Therefore, it is of great significance to design and prepare a tibial implant with good biocompatibility and excellent comprehensive mechanical properties. In this paper, with 316L stainless steel powder as the main material, a personalized artificial tibia design and processing method based on laser powder bed fusion is proposed. Firstly, the personalized model of the damaged part of the patient is reconstructed. Then, the porous structure of human tibia is manufactured by selective laser melting technology. To research the factors affecting the quality of selective laser melting porous structure, a laser heat source model, heat transfer model and molten pool model of laser powder bed fusion process were constructed; then, by changing the laser process parameters (laser power, laser beam diameter, scanning speed, powder layer thickness, etc.) to conduct multiple sets of simulation experiments, it is obtained that when the “laser power is 180 W, the laser scanning speed is 1000 mm/s, the laser beam diameter is 80 μm, the powder layer thickness is 50 μm”, the porous stainless steel parts with better quality can be obtained. Finally, the porous structure was fabricated by selective laser processing, and its properties were tested and analyzed. The experimental results show that the cell side length of cube is 1.2 mm, the elastic modulus of octahedral porous structure with pillar diameter of 0.35 mm is about 17.88 GPa, which match well with tibial bone tissue.