Production of Hydroxyapatite (HAp) nanoparticles by Sol-Gel method

Abstract

Hydroxyapatite (HAp) with chemical formula of Ca₁₀(PO₄)₆(OH)₂ is one of well -known bioceramic from calcium phosphate (CaP) family because of the similarities between natural bone minerals and posseses the biological properties of biocompatibility and bioactivity make it important for artificial bone substitute. Sol-gel method is much more preferred with the advantage of possibility of a strict control of process parameters. The synthesis routes using precursor of calcium nitrate tetrahydrate (Ca(NO₃)₂∙H₂O) and phosphoric pentoxide (P₂O₅) with different stirring speed from 100 rpm to 500 rpm, aging time from 1 hour to 5 hours and sintering temperature from 600°C to 800°C. Characterisation of HAp is carried out using FTIR for functional groups identification which were hydroxyl (3570 cm-1) and phosphate (1087 cm-1), XRD for phase composition showed the sharp peaks at angle 31.8o and 26o proved the formation of HAp and calculate crystallite size using Scherrer’s formula had calculated the range of size from 28.621nm to 34.726 nm and SEM for particle morphology observed that highly agglomerated of particle HAp. In order to optimize the process conditions, Response Surface Methodology (RSM) was employed by choosing Central Composite Design (CCD) has optimized the conditions of stirring rate of 300 rpm, 3 hours aging time and 700°C of sintering temperature, the resultant size was 32.5126nm.