Synthesis and characterization of nanocrystalline hydroxyapatite gel and its application as scaffold aggregation

The sol-gel process is used to synthesise materials from colloidal suspensions and, therefore, is suitable for preparing nanomaterials. Hydroxyapatite Ca10(PO4)6(OH)2 is a bioactive ceramic which is found in the mineral phase of bone tissue and is known for its great potential in tissue engineering applications. It can be applied as particle aggregates on ceramic slurry, coating or film on materials with a poorer biological response than hydroxyapatite. Hydroxyapatite gel was obtained by the sol-gel process and applied as nanoparticle aggregation in the mixture of hydroxyapatite and tricalcium phosphate to form a ceramic slurry. This process is the polymer foam replication technique, used to produce tissue engineering scaffolds. Environmental SEM, TEM, EELS, SEM, XRD and XRF were used for HA gel characterisation. The crystallite size was calculated from XRD data using the Scherrer equation. The nanoparticle size before firing was approximately 5 nm. The crystallite size calculated after calcination was approximately 63 nm. EELS results showed that calcium phosphate was obtained before firing. After HA gel calcination at 500 C, XRD showed hydroxyapatite with a small content of beta-TCP. The scaffolds obtained by the polymer foam replication technique had a morphology with adequate porosity for tissue engineering.