Preparation and characterization of hydroxyapatite powder for biomedical applications from giant African land snail shell using a hydrothermal technique

摘要

The need for hydroxyapatite synthesized from an inexpensive raw material is on the increase due to the expense of high purity calcium and demand of hydroxyapatite powder in dentistry, orthopaedics and trauma surgery. Additionally, efforts towards recycling and reuse of waste into value added products such as hydroxyapatite, have been one of the targeted goals of the SDG by the year 2030 to improve healthcare and for environmental friendliness. Giant African land snail shells (Archachatina marginata) are a waste material that is now being considered for use as a calcium precursor for hydroxyapatite production. Additionally, the effect of various low temperature hydrothermal treatments on the properties of hydroxyapatite derived in this manner are presented. Snail shell powder calcined at 900?°C for 3 hours in a bench top electric furnace was used in the current study as calcium precursor. Hydroxyapatite (HA) powder was prepared via a hydrothermal technique at 100, 150 and 200 °C for 4 hr of soaking time. Characterization of calcined and un-calcined snail shell as well as hydroxyapatite powders was done using XRF, XRD, FTIR, SEM/EDS to determine the phase content, functional groups, morphology and elemental composition, respectively. Results of calcination indicated a 81.80% CaO yield compared to 66.4% for un-calcined snail shell powder. The outcome of XRD and FTIR analyses of hydroxyapatite powders produced under various hydrothermal treatments compare favourably with HA currently available on the market. The hydrothermal temperature influenced the crystallite size and microstructure of hydroxyapatite powder. A minimum crystallite size of 23.1 nm with Ca/P stoichiometric ratio of 1.6, suitable for biomedical applications, was obtained at 100 °C. This is compared to a crystallite size of 50.58 nm for commercial hydroxyapatite examined under the same conditions. Hence, African giant snail shells can serve as inexpensive calcium source for nano-hydroxyapatite powder production that is useful in biomedical applications.