Natural and synthetic hydroxyapatite filled PCL: Mechanical properties and biocompatibility analysis

Hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) is one of the most biocompatible ceramics because it is similar to the mineral constituents of human bone and teeth. Composites of hydroxyapatite (HA) and biodegradable polymers such as polycaprolactone (PCL) are interesting materials for medical applications, especially for bone replacement. With the aim to improve the properties of biodegradable polyester-based devices, we have prepared and characterized novel composites made of polycaprolactone and natural or synthetic hydroxyapatite. The composites were screened for cytocompatibility by a direct contact method, in view of the future application of these hydroxyapatite filled PCL polymers as scaffolds for bone engineering. Primary cultures of human bone marrow mesenchymal stem cells (MSC) were selected as the most appropriate models to study the in vitro performance of these materials. The results showed that all materials have good biocompatibility and allow expression of the osteoblastic features. Scanning electron microscopy provided direct evidence of intense cell adhesion and proliferation on the tested materials.