Design and Preparation of a Biodegradable Scaffold Based on Poly (?-Caprolactone) and Nano Powder Flouradated hydroxyapatite for Bone Tissue Engineering In this study, poly (?-caprolactone)/ nano fluoridated hydroxyapatite (PCL-FHA) scaffold were produced. Fluoridated hydroxyapatite (FHA) nanopowders had a chemical composition of Ca 10 (PO 4 ) 6 OH 2 ? x F x (where x values were selected equal to 0.5, 1, 1.5 and 2.0). Different weight fractions of 10, 20, 30 and 40% of the FHA were added to the PCL. PCL-FHA scaffolds were prepared by solvent casting / particulate leaching method. Sodium chloride (NaCl) particle was used as a porogen with diameters 250–400 ?m. Structural, chemical, mechanical, bioactivity, biodegradation and biocompatibility properties of scaffolds were evaluated. The pore morphology, size, and distribution of the scaffolds were characterized using a scanning electron microscope (SEM). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to determine the phase structure, chemical composition and functional groups of scaffolds. Porosity of the scaffolds was measured using Archimedes’ Principle according to a known method. These scaffolds were evaluated for their compressive mechanical properties. The bioactivity of the nanocomposite scaffolds was evaluated by soaking the scaffolds in a simulated body fluid (SBF) up to 4 week. The changes of pH of the SBF medium were measured at pre-determined time intervals using a pH meter. The calcium and phosphorous ions concentrations of SBF medium were determined using ICP-OES analysis. The apatite formation on the surface of the scaffolds as consequence of the dissolution and precipitation process of calcium phosphate was investigated by scanning electron microscopy (SEM). In vitro degradation was studied by immersing of scaffolds in phosphate buffered saline () up to 30 days. The changes of pH of the and the changes of the weight loss of the scaffolds were measured. MTT test carried out to investigate the cytotoxicity, cell proliferation and cell attachment. Results showed a uniform scaffold, relatively that by increasing of NaCl amount, its porosity was increased. Compressive strength, bioactivity and biodegradation of scaffolds increased with the increasing the weight ratio of FHA. Compressive strength also decreased with the increasing of the porosity and the fluorine content of FHA. However, biodegradation of scaffolds increased by increasing of the fluorine content of FHA. The increase in ionic concentration of calcium and phosphorus as well as the increase in pH after SBF immersion resulted in an increase in ionic activity product of apatite in the solution.
