Production of Hydroxyapatite (HAp) nanoparticles by direct precipitation

Abstract

Hydroxyapatite (HAp) nanoparticles, Ca10(PO4)6(OH)2 are biomaterial that are applied in various biomedical and drug delivery system. Stoichiometric HAp nanoparticles are generated from calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) and ammonium phosphate ((NH4)3PO4) via direct precipitation method. The main and interactive effects of factors such as mixing temperatures and stirring speeds on HAp nanoparticles’ crystallite size are investigated by using Response Surface Methodology (RSM) and Central Composite Design (CCD). The HAp powder characterization (phase composition, functional groups, and morphology) is analyzed by using X-Ray Diffractometer (XRD), Fourier Transform InfraRed Spectrometer (FT-IR) and Scanning Electron Microscope (SEM). The highest peak of 31.7919⁰ at 2θ indicated the presence of s-HAp in the sample. Phosphate (P-O), hydroxyl (O-H), and carbonate (C-O) functional groups are identified in the FT-IR spectra pattern of samples. The morphology of the product powder appeared as agglomerates. Optimization study of process parameters in synthesis smallest size of HAp nanoparticles is carried out by using Design of Experiment (DOE). Smallest crystallite size of HAp nanoparticles at 37.5606 nm is obtained at optimum condition of 40⁰C and 500 rpm.