Synthesis and characterization of pure and Mg, Cu, Ag, and Sr doped calcium-deficient hydroxyapatite from brushite as precursor using the dissolution-precipitation method

Calcium-deficient hydroxyapatite (CDHA) is an attractive biomaterial for medical applications due to its similarity with the mineral part of bones. This study presents, for the first time, the preparation of CDHA form brushite as a starting precursor through dissolution-precipitation process. To further enhance its potential in vivo performance, CDHA was doped with some biologically relevant ions such as Mg2+, Sr2+, Cu2+, and Ag+. X-ray diffraction and ATR-FTIR analyses indicated that the samples were poorly crystalline, nonstoichiometric, and nanometric. BET analysis confirmed that the CDHA powders have a high specific surface area (SSA). Furthermore, crystallinity, lattice parameters, chemical composition, and SSA were significantly influenced by the substituted ion nature. Later, prepared samples were sintered at 1000 degrees C, and the structural characterization revealed that all CDHA were unstable and transformed, into p-TCP. Overall, using brushite as a starting material and dissolution-precipitation process appears an effective approach for synthesizing CDHA for bone treatment applications.