Titration route affects biomimetic mineralization of carbonated hydroxyapatite bone material

Abstract

Carbonated hydroxyapatite (CHAp) was prepared from snail shells calcined at 850 °C (calcined powder) and a diammonium hydrogen phosphate (DHP) solution for bone material. The titration route of the preparation was varied (route A and route B) to have two products (CHApA and CHApB). In route A, DHP solution was titrated against calcined powder (CP) solution to produce CHApA, whereas in route B, CP solution was titrated against DHP solution to produce CHApB. Thermogravimetric analysis-differential scanning calorimetry (TGA–DSC) showed different thermal profiles for the CHAps, which resulted in different morphologies that influenced mineralization. The mineralization studies of the CHAps were performed in simulated body fluid (SBF) for 7, 14, and 21 days. The X-ray fluorescence (XRF) data of the SBF solution before and after CHAp immersion showed that CHApB has higher dissolution of Ca and P minerals on day 14 than CHApA. Similarly, on day 21, the mineral uptake by the CHAp was higher in CHApB than in CHApA. Scanning electron microscopy (SEM) images showed spheroids and apatite-like bundles in CHApB but were absent in CHApA. In addition, X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy confirmed the growth of carbonated apatite that started from day 14 to day 21. The findings indicate that the titration routes have a great influence on the formation of a highly resorbable material for bone implant coatings and augmentation applications.