A new thermoshock-based method for rapid preparation of ultra-pure hydroxyapatite nanodebris from bovine bone

Abstract

Hydroxyapatite can be obtained in its ultra-pure form and ultra-small size under appropriate thermal treatments. To prepare hydroxyapatite nanostructures, commercial bovine bone was heated to 900 °C before the red-hot specimens were rapidly quenched by a water bath at 4 °C. TEM images reveal a debris-like morphology at nanoscale with average size observed under 10 nm. XRD patterns prove neither phase change nor crystalline impurity occurring given the correspondence of all registered peaks with ICDD-PDF No. 00.024.0033. Scherrer’s equation estimates the mean size of granular grains at ca. 5 nm, confirming a quasi-monocrystalline structure going by the consistency with TEM result. EDX data provides demonstration for a high degree of purity, borne out by exclusive five elements Ca, P, Mg, Na, and O trace-detected. The average Ca/P ratio of 1.87 is consistent with the acceptable range for biological hydroxyapatite. Thermal shock behaviour of brittle ceramic hydroxyapatite at nanoscale speculates a top-down approach for the mechanism. Chitosan- and glucosamine-based functionalisation proves potentiality in biological application of the prepared hydroxyapatite nanomaterials. The results introduce a contamination-free and time-effective procedure to prepare biocompatible hydroxyapatite nanostructures from biological sources.