Synthesis and Hydrolysis of Brushite (DCPD): The Role of Ionic Substitution

Brushite (dicalcium phosphate dihydrate, DCPD) is considered one of the possible precursors of the apatitic phase that constitutes the mineral component of bones, and it is often utilized in the preparation of biomaterials for hard tissue repair. In this work, we investigated the influence of ionic substitution on the synthesis, structure, and morphology of this calcium phosphate, as well as on its hydrolysis process. The results of structural refinements indicate that the range of possible substitution can reach values up to about 38 atom % for the big Sr ion, whereas it is quite limited for Zn, Co, and Mn. In particular, DCPD cannot be obtained as a single phase in the presence of zinc ions in solution. The kind and amount of substituent ions significantly influence the morphology of DCPD, promoting aggregation and crystal shape modifications, as well as its hydrolysis in solution. The results provide useful information for the understanding of the mineralization processes and for the design of new biomaterials.