Evaluation of mechanical properties and apatite formation of synthesized fluorapatite-hardystonite nanocomposite scaffolds

In this study, mechanical properties and apatite formation ability of synthesized fluorapatite-hardystonite (FA-HT) nanocomposite scaffolds were investigated. Hardystonite (HT; 5 and 10 wt.%) as a reinforcement phase was incorporated into the FA scaffold. FA was mixed with HT for 4 h under argon gas at 220 °C. A space holder method was used for fabricating porous FA-HT scaffolds. Sodium chloride (NaCl) was used as pore-forming agent in this method. Then, the powder was compacted under a pressure of 220 MPa. Finally, the samples were sintered at 1000 ºC for 2 h. The X-ray diffraction (XRD) results of the synthesized scaffolds confirmed the formation of FA and HT powders. Studying the microstructure of the samples showed that synthesized scaffolds had a porous structure with interconnected pores, similar to the porosity degree of natural bones. The results also revealed that the mechanical properties of scaffolds were improved; the compressive strength values of the FA-5HT and FA-HT scaffolds were obtained 1.6 MPa and 2.8 MPa, respectively. The young modulus values for these scaffolds were 5.5 MPa and 12.4 MPa, respectively. Results of bioactivity test showed the ratio of calcium to phosphate (Ca/P) in scaffolds was 1.71±0.3 and 1.60±0.5 for FA-5HT and FA-10HT samples, respectively. Based on the results, FA-HT scaffolds have desirable mechanical properties and suitable level of bioactivity which can be used as new and promising biomaterials in bone tissue engineering and repairing bone defects.