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Hydroxyapatite (HA) is a well-known material for biomedical applications and its performance depends greatly on its morphological features. Therefore, preparation of mesoporous HA with high surface area and adsorption capacity is highly deserved. In this research, a hydrothermal approach to synthesize mesoporous HA without post-processing calcination step is presented. The possibility using different polyphenols to generate mesoporous HA as well as using different phosphate sources to tailor the morphological features of HA is investigated. The as-prepared mesoporous HA particles are characterized by XRD, FTIR, SEM, TEM, BET, and zeta potential. Besides, the impacts of HA morphological features on model drug Dox are also studied. It is expected the strong interaction between –OH of polyphenols and Ca 2+ makes polyphenols molecules occupy the inner sites of growing HA particles. After the removal of polyphenols by hydrothermal treatment and ethanol extraction, the occupied sites are transformed into mesopores. The typical mesoporous HA generated in present work has a rod-like morphology with BET specific surface area of 106.6 m 2 /g and an average pore size of 14.4 nm. [ABSTRACT FROM AUTHOR]

Biphasic calcium phosphate (BCP) compositions consisting of β-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP) are potential biodegradable ceramics for bone regeneration. The present work demonstrates the formation of such dense ceramics by first preparing the precursors of nano-sized, amorphous, and equiaxed calcium pyrophosphate particles, and then sintering the precursors at 900 °C to transform them into desired BCP. However, if the complex of calcium tripolyphosphate was used, only CPP could be generated. It was also observed that the incorporation of Mg 2+ had several effects on the resulting products including: (1) promoting the generation of meso-porous precipitates; (2) favoring the formation of β-TCP instead of CPP; (3) reducing the grain size and increasing the density of the sintered ceramics, and (4) enhancing the negative electric charge of the BCP surface. Thus, the as-prepared BCP ceramics can serve as potential bone substitute materials in orthopedic applications. [ABSTRACT FROM AUTHOR]