Nanostructured surface bioactive composite scaffold for filling of bone defects
Leonardo Ciocca, Isidoro Giorgio Lesci, Sara Ragazzini, Sabrina Gioria, Andrea Valsesia, Annapaola Parrilli, Alessandro Spadari, Dozza Barbara, MORA PAOLO, Adriano Piattelli, Giovanna Iezzi, Achille Tarsitano, Baldissara Paolo
Abstract
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.