Deposition of Hydroxyapatite on Silica Made from Rice Husk Ash to Produce the Powder Component of Calcium Phosphate Cement

Abstract

Hydroxyapatite (HA) has been deposited on silica (SiO2) particles to produce HA-SiO2 composite that will be used as the powder component of calcium phosphate cement. HA was expected to be on the composite surface to maintain its bioactivity. SiO2 was made by the sol-gel method, in which silicate solution was extracted from rice husk ash with NaOH solution. Deposition of HA on SiO2 was carried out by wet chemical deposition method at various Ca/Si molar ratio (in a range of 5–25) followed by calcination at 600 °C for 2 h. Results showed that HA was successfully deposited on SiO2 particles. The cell parameters of the HA crystals were slightly distorted by the presence of SiO2 and HA in the composite had a bigger cell volume than pure HA. The crystallite size of HA in the composites increased with the increase of the Ca/Si ratio but the values were smaller than pure HA. SiO2 acted as a morphology directing agent. At low Ca/Si ratio, the HA-SiO2 particles were in a form of short rod-like particles with sizes of < 50 nm, while at high Ca/Si ratio, a mixture of short and long rod-like particles with the size of < 100 nm was obtained. The zeta potential of composites was almost similar to pure HA. These properties indicated that HA-SiO2 composites support the bioactivity of injectable calcium phosphate cement.

Calcium Phosphate Cement Composed of Hydroxyapatite Modified Silica and Polyeugenol as a Bone Filler Material

“…Some of PO 4 3in the HA structure were substituted by CO 3 2− groups due to the presence of a peak at 1489 cm −1 . The Si-O-Si asymmetric stretching vibration coincides with the PO 4 3− asymmetric stretching vibration peak at 1088 cm −1 [11]. The HASiO 2 and PE spectral patterns were found in the HASiO 2 _PE spectra, but the peak intensity of PE in HASiO 2 _PE is lower than HASiO 2 due to its low concentration (10%).…”

“…The synthesis of hydroxyapatite-modified silica was conducted according to the previous work [11]. A 50 mL of a solution that contained Ca(NO 3 ) 2 •4H 2 O 1.2 M, SiO 2 0.048 M, and CTAB (0.045 mmol) was slowly added by 50 mL of a solution that contained KH 2 PO 4 1 M and CTAB (0.045 mmol).…”

“…HA, which is composited with SiO 2 from rice husk, shows that HA covers the surface of the composite. Therefore, the biocompatibility and bioactivity properties of HA can be preserved [11].…”

“…In this study, the HASiO 2 was synthesized in situ by the sol-gel method using cetyltrimethylammonium bromide (CTAB) surfactant as a morphology-directing agent [21][22]. PE was synthesized by polymerization of eugenol using BF 3 catalyst [10][11][12]. Both were used to make CPC by mixing with 2.5% Na 2 HPO 4 solution in a ratio of 1:1 (w/v).…”

Effect of Sensitive pH on Hydroxyapatite Properties Synthesized from Chicken Eggshell

“…The addition of CaO reduces the surface area of the composite. The reduced surface area is undesirable for the powder component of Calcium phosphate cement (CPC) since the presence of silica on the composite surface, and the composite's decreased surface area diminishes the bioactivity of HA [6]. Biocompatibility is a critical feature of 3D scaffolds designed for biomedical purposes.…”