Development of Porous Nano-Hydroxyapatite from Austromegabalanus psittacus Marine Species Using Camphor and Wheat Flour as Pore Formers

Nano-hydroxyapatite (Ca-10 (PO4)(6)(OH)(2) exhibiting potential biocompatibility and compositional similarity to natural bone leads to the clinical solution/substitute to diseased/damaged parts of bone due to trauma. Porous bio active nano-hydroxyapatite can bond with host cell/tissue as implant. Abundant marine sources can be used to develop biocompatible material though novel chemical method. Marine resources, like skeletons of shells, corals, oysters, fish bones etc., are composed of calcium compound in the form of aragonite/calcite/veterite (calcium carbonate). Austromegabalanus psittacus has been opted for extraction of hydroxyapatite. Calcined aragonite mixed with distilled water and ortho phosphoric acid accordingly while maintaining the stoichiometric ratio of Ca/P equal to 1.67. Crystallite size of 62 nm was obtained using X-ray diffraction. Fourier transform infrared spectroscopy confirms the presence of all characteristic bonds of hydroxyapatite, namely PO43- distinguishable peak in the spectra. Porous hydroxyapatite based biomaterials having interconnected pores, are suitable for biological implants, such as bone tissue growth and vascularization: was developed with the help of pore former, camphor and wheat flour, with a weight percentage of 10, 20, 30, 40 and 50 to hydroxyapatite. Hydraulic pressed porous hydroxyapatite pellets were sintered at 1100 degrees C with a controlled heating (5 degrees C/min). Porous hydroxyapatite surface morphology shows interconnected pores of size 0.89 +/- 0 .24 mu m and near hexagonal shaped grins of size 1.85 +/- 0.69 mu m. Sintered hydroxyapatite is composed of irregular polygonal shaped grains with interconnected pores. In comparison with camphor, wheat flour emerges as a good pore former in terms of porosity of 45% obtained with the addition of 10 weight% without losing strength like, compressive strength 13.5 N/mm(2) and Modulus of elasticity, 1.3 GPa. Without addition of pore former, sintered hydroxyapatite exhibits compressive strength 55 N/mm(2) and modulus of elasticity 4 GPa. Porous nano-hydroxyapatite could have suitable applications as implants for the repair/replacement of defective bone