Comparison of template mediated ultrasonic and microwave irradiation method on the synthesis of hydroxyapatite nanoparticles for biomedical applications

Abstract

We have reported a template directed synthesis of hydroxyapatite nanoparticles from CaCl2·2H2O and (NH4)2HPO4 as calcium and phosphate precursors respectively, by ultrasonic irradiation method. The effect of template tryptophan addition, the influence of microwave irradiation and ultrasonic irradiation on the purity, structural and morphological properties of hydroxyapatite nanoparticles were investigated during its synthesis. FT-IR and XRD analysis were carried out to identify the phase and the purity of the as-synthesized nanoparticles and the results eventually claimed that the formation of hydroxyapatite in all synthesis conditions. Moreover, it is evident that microwave as well as the ultrasonic irradiation method is rapid synthesis routes for HAP when compared to conventional heating method with and without template addition. But the morphological evaluation using SEM and TEM analysis clearly emphasized that the combination of template tryptophan with the Ca/P precursors and the assistance of microwave /ultrasound irradiation can effectively regulate and reduce the size of the hydroxyapatite nanoparticles. Particularly, the application of an ultrasound irradiation during the synthesis of HAP facilitates the size of the nanoparticles below 30 nm with uniform cylindrical morphology. Hence, the HAP nanoparticles synthesized by template directed ultrasonic irradiation method can act as a better biomaterial for hard tissue replacement applications.