Fabrication and properties of poly(vinyl alcohol)/β-tricalcium phosphate composite scaffolds via fused deposition modeling for bone tissue engineering

Polymer/bioceramic composite scaffolds have been widely regarded as promising biomimetic substitutes for bone tissue engineering owing to their tailored mechanical properties and improved bioactivity. Fused deposition modeling (FDM), which is a simple and cost-effective 3D printing technology, enables the fabrication of scaffolds with predetermined and controllable internal architecture. In this study, poly(vinyl alcohol)/beta-tricalcium phosphate (PVA/beta-TCP) composite scaffolds were constructed using FDM. The thermal behavior, printability, microstructure and mechanical properties of the composite scaffolds were investigated. The results showed that beta-TCP particles were homogeneously dispersed into the PVA matrix with the assistance of solid state shear milling. Hydrogen bonding interactions were formed between beta-TCP and PVA, which helped to improve the interface strength of the composites. By using water and glycerin as a co-plasticizer, the as-prepared composite filaments that were suitable for the FDM process exhibited improved thermal processability. In addition, the printability window of the material was theoretically established based on the ratio of its compressive modulus to the apparent viscosity. SEM and mu CT analyses indicated that as-fabricated scaffolds had well-structured shapes and totally interconnected channels. Meanwhile, the loading-bear capabilities of the composite scaffolds were significantly enhanced with an increase in the beta-TCP content up to 20 wt%; e.g., the maximum stress increased from 8.3 to 10.7 kPa. Moreover, in vitro cell culture studies revealed that the resulting composite scaffolds possess good biocompatibility, which is favorable to cell adhesion and proliferation. These results strongly indicate the potential of the fabricated scaffolds in tissue engineering applications.