Surface modification of three-dimensional Ca-P/PHBV nanocomposite scaffolds by physical entrapment of gelatin and its in vitro biological evaluation

The properties of bone tissue engineering scaffolds such as architecture, porosity, mechanical properties and surface properties have significant effects on cellular response and play an important role in bone regeneration. In this study, three-dimensional nanocomposite scaffolds consisting of calcium phosphate (Ca-P) nanoparticles and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) copolymer with controlled external and internal architectures were successfully produced via selective laser sintering (SLS), one of the versatile rapid prototyping techniques. The Ca-P/PHBV nanocomposite scaffolds had a porosity of (61.75 +/- 1.24)%, compressive strength of (2.16 +/- 0.21) MPa and Young's modulus of (26.98 +/- 2.29) MPa. The surface modification of scaffolds by gelatin was achieved through physical entrapment. The amount of entrapped gelatin could be controlled by varying the solvent composition and reaction time. The surface modification improved the hydrophilicity of scaffolds but did not significantly affect the surface morphology and mechanical properties. Osteoblast-like cells (SaOS-2) were cultured on scaffolds with and without gelatin surface modification. The majority of SaOS-2 cells were viable and proliferated in both types of scaffolds for up to 14 d in culture, as indicated by MTT assay and live and dead assay. Surface modification significantly increased cell proliferation for surface modified scaffolds, which could be due to the improvement in hydrophilicity of the scaffolds.