Nanostructured surface bioactive composite scaffold for filling of bone defects

The aim of this study was to investigate the chemical and physical surface properties of a hybrid nano-hydroxyapatite/collagen/polycaprolactone (nHA/Coll/PCL) material, and to test its in vitro biocompatibility and in vivo osteointegration. Mineralized collagen fibers with nHA were admixed with PCL at a weight proportion of 50:50. The material was characterized by transmission X-ray diffraction (XRD), electron microscopy (TEM), atomic force microscopy (AFM), force spectroscopy, X-ray Photoemission Spectroscopy (XPS), and biocompatibility testing using human mesenchymal stem cells (MSCs), and Hepatocyte carcinoma (HePG2) and primary osteogenic sarcoma (SAOS-2) cells as complementary tests. In addition, the ability of this material to fill three-wall bony defects was tested in the mandible of a sheep. The material had confirmed the relative low crystallinity of the HA having a nano-sized dimension, which was composed of only oxygen, carbon, calcium and phosphorus, without no residual cytotoxic element. Human MSCs on the surface scaffold showed high metabolic activity and a high rate of viability. Biocompatibility complementary testing using HePG2 and SAOS-2 cells showed good metabolic activity, and the lactate dehydrogenase assay using HePG2 cells demonstrated no significant cytotoxicity. Histological analysis of the in-vivo experimentation showed osteointegration of the material and the absence of inflammatory cells at the bone–scaffold interface. Some areas showed bone-cell seeding and isolated agglomerates of bone cells were evident in the inner scaffold.