Evaluation of three-dimensional scaffolds made of blends of hydroxyapatite and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) for bone reconstruction

Hydroxyapatite (HAP) was blended into poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) to make films and scaffolds. After HAP blending, mechanical properties of PHB including compressive elastic modulus and maximum stress showed improvement and osteoblast responses including cell growth and alkaline phosphatase activity were also strengthened. On the other hand, scaffolds made of PHBHHx blended with HAP had an adverse effect. No remarkable change on degradation of PHB or PHBHHx blended with HAP, respectively, was observed in simulated body fluid. Scanning electron microscopy examination revealed that osteoblast responses to HAP incorporation may be related to surface morphology and to the exposed HAP particles on polymer surface. All these results indicated that the blending of HAP particles into PHBHHx scaffolds fabricated by salt leaching was unable to either strengthen its mechanical properties or enhance osteoblast responses. Although HAP is bioactive and osteoconductive, its blending with PHBHHx did not generate a better performance on bone reconstruction.