Optimized fabrication of Ca-P/PHBV nanocomposite scaffolds via selective laser sintering for bone tissue engineering

Biomaterials for scaffolds and scaffold fabrication techniques are two key elements in scaffold-based tissue engineering. Nanocomposites that consist of biodegradable polymers and osteoconductive bioceramic nanoparticles and advanced scaffold manufacturing techniques, such as rapid prototyping (RP) technologies, have attracted much attention for developing new bone tissue engineering strategies. In the current study, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microspheres and calcium phosphate (Ca-P)/PHBV nanocomposite microspheres were fabricated using the oil-in-water (O/W) and solid-in-oil-in-water (S/O/W) emulsion solvent evaporation methods. The microspheres with suitable sizes were then used as raw materials for scaffold fabrication via selective laser sintering (SLS), which is a mature RP technique. A three-factor three-level complete factorial design was applied to investigate the effects of the three factors (laser power, scan spacing, and layer thickness) in SLS and to optimize SLS parameters for producing good-quality PHBV polymer scaffolds and Ca-P/PHBV nanocomposite scaffolds. The plots of the main effects of these three factors and the three-dimensional response surface were constructed and discussed. Based on the regression equation, optimized PHBV scaffolds and Ca-P/PHBV scaffolds were fabricated using the optimized values of SLS parameters. Characterization of optimized PHBV scaffolds and Ca-P/PHBV scaffolds verified the optimization process. It has also been demonstrated that SLS has the capability of constructing good-quality, sophisticated porous structures of complex shape, which some tissue engineering applications may require.