Synthesis of hydroxyapatite from cuttlebone under various pH conditions: An approach for medical materials

Abstract

To support the bio-based economy, development on hydroxyapatite from cuttlebone was investigated. Cuttlebone is naturally occurring source of calcium. We calcined it at 700°C for 2 h to form a calcium oxide powder. Hydroxyapatite was coprecipitated with calcium oxide powder and phosphoric acid. The effect of the pH ranging from 6–10 was controlled by adding ammonium hydroxide. Fourier transform infrared and X-ray diffraction were employed to characterize the structural properties of the hydroxyapatite. Changes in pH did not affect the structural properties of the hydroxyapatite. Thermogravimetric analysis revealed that the hydroxyapatite was thermally stable up to 700°C. At a neutral pH, scanning electron microscopy revealed the presence of rod-like structures. However, at a basic pH, it had a spherical shape due to the high mobility of Ca²⁺ and PO₄^3-. The specific surface area, pore volume and pore size were estimated to be 5-15 m²Â·g^-1, 0.05-0.1 cc·g and 15-25°A, respectively. It was tested for cytotoxicity, and cells were able to grow under all conditions used to produce the hydroxyapatite. Hydroxyapatite prepared from cuttlebone can be used as a medical material. The objective of this research work is to encourage the use of bio-based material in medical application.