In this study, graphene oxide (GO) is incorporated into poly(vinyl alcohol) (PVA) for the purpose of improving the mechanical properties. Nanocomposite scaffolds with an interconnected porous structure are fabricated by selective laser sintering (SLS). The results indicate that the highest improvements in the mechanical properties are obtained, that is, a 60%, 152% and 69% improvement of compressive strength, Young's modulus and tensile strength is achieved at the GO loading of 2.5 wt%, respectively. The reason can be attributed to the enhanced load transfer due to the homogeneous dispersion of GO sheets and the strong hydrogen bonding interactions between GO and the PVA matrix. The agglomerates and restacking of GO sheets occur on further increasing the GO loading, which leads to the decrease in the mechanical properties. In addition, osteoblast-like cells attach and grow well on the surface of scaffolds, and proliferate with increasing time of culture. The GO/PVA nanocomposite scaffolds are potential candidates for bone tissue engineering.

The rapid degradation rate of Magnesium (Mg) alloy limits its biomedical application even though it possesses outstanding biological performance and biomechanical compatibility. In this study, a combined method of laser rapid melting and alloying Zinc (Zn) was proposed to decrease the degradation rate of Mg-Sn alloy. The microstructure, degradation behaviors and mechanical properties of the laser-melted Mg-5Sn-xZn (x = 0, 2, 4, 6 and 8 wt.%) alloys were investigated. The results indicated that the grain size of the alloys decreased with increasing Zn content, due to the increased number of nucleation particles formed in the process of solidification. Moreover, the laser-melted Mg-Sn alloys possessed finer grains compared with traditional as-cast and as-rolled Mg-Sn alloys. The degradation rate of the alloys decreased with increasing Zn content (0-4 wt.%), which was ascribed to the grain refinement and the formation of Zn(OH) protective layer. However, the degradation rate increased as the Zn content further increased (4-8 wt.%), which was caused by the galvanic corrosion between the Mg matrix and the generated MgZn phase. Besides, Zn also increased the hardness of the alloys owing to the grain refinement strengthening and solid solution strengthening.

Porous poly(vinylidene fluoride) (PVDF) scaffolds were prepared by selective laser sintering. The effects of laser energy density, ranging from 0.66 to 2.16 J/mm2, on microstructure and mechanical properties were investigated. At low energy density levels, PVDF particles could fuse well and the structure becomes dense with the increase of the energy density. Smoke and defects (such as holes) were observed when the energy density increased above 1.56 J/mm2which indicated decomposition of the PVDF powder. The scaffolds appeared to be light yellow and there was a reduction in tensile strength. The fabricated scaffolds were immersed into simulated body fluid for different time to evaluate biostability. In addition, MG63 cells were seeded and cultured for different days on the scaffolds. The testing results showed that the cells grew and spread well, indicating that PVDF scaffolds had good biocompatibility.

Based on the two-mode phase field crystal (PFC) model and the principle of the common tangent, a two-dimensional PFC phase diagram is established. According to the phase diagram, the parameters for a steady growth of the hexagonal and the square phase are found. Moreover, the nucleation and growth characteristics of the square phase from hexagonal phase under different pressures are simulated by using these parameters. The movements of dislocation core under pressure at different transformation stages are revealed and compared with each other. Finally, by changing the grain orientation, the formation and disappearance of grain boundaries at different angles are simulated and analyzed.

Polyglycolide (PGA) is considered an attractive candidate for bone regeneration because of its good biodegradability as well as biocompatibility. However, its insufficient mechanical strength and inadequate bioactivity limit the applications. In this research, diopside (DIOP) was incorporated into PGA scaffolds for enhancing mechanical and 10 biological properties. The porous scaffolds were fabricated via selective laser sintering (SLS). The effect of DIOP content on the microstructure, mechanical properties, bioactivity as well as cytocompatibility of the porous scaffolds was studied. The results showed that DIOP particles were homogenously distributed within the PGA matrix, which contained up to 10 wt%. This led to an improvement of 171.2% in compressive strength 15 and 46.2% in compressive modulus. In vitro studies demonstrated that the highest apatite forming ability was obtained on the scaffolds surface with the highest amount of DIOP after soaking in simulated body fluid (SBF), suggesting the bioactivity of the scaffolds increased with increasing DIOP. In addition, a cytocompatibility study showed that the scaffolds exhibited a higher degree of cells attachment, growth as well as differentiation 20 than the pure PGA scaffolds. These indicated that the PGA scaffolds modified with DIOP possessed the suitable properties, which could be used for bone tissue regeneration.