3D Printed HA/β-TCP Scaffold: A Macroscopic Microscopic Analysis and Biological Validation Study of the Effect of the Component Ratio on Performance.

The component ratio of a material is the key factor determining the quality of three-dimensional (3D)-printed scaffolds. This study aimed to investigate the basic properties of hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) scaffold material with poly(vinyl alcohol) (PVA) as a binder. The interfacial binding energies, bonding behaviors, and mechanical characteristics of the materials were investigated by molecular dynamics simulation (MD), and it was found that the types of functional groups and the molar occupancy of elements affected the interfacial binding behaviors of the materials. Moreover, the properties of the slurry and structural characteristics of the scaffolds at different HA/β-TCP component ratios were analyzed. The variation in the shear-thinning capacity of the slurry was explained by investigating the zeta potential, solid content, and interfacial binding energy of the materials. The basic properties of the material were not the only factors determining the mechanical properties of scaffolds; the pore and bonding characteristics, and the interfacial binding energy of the material together determine the mechanical properties of scaffolds. These analyses elucidated the impact of the component ratio on the scaffolds from both microscopic and macroscopic perspectives. Finally, the biological characterization study of the material was verified by in vitro simulation experiments, and it was found that scaffolds containing β-TCP demonstrated relatively better performance in supporting bone tissue formation compared with β-TCP-free controls. This research provides a theoretical foundation for the selection and optimization of material combinations in 3D printing applications.