Tuning the properties of magnesium phosphate-based bone cements: Effect of powder to liquid ratio and aqueous solution concentration

The use of magnesium phosphate-based cements (MPCs) in the biomedical field has recently come under investigation in the scientific community, as these materials display many intriguing properties in the replacement and/or integration of calcium phosphate-based bone cements; however, the diverse preparation conditions reported in the literature make it difficult to evaluate how the modification of a specific parameter in the preparation of the paste affects the final properties of the material. In this paper, we prepared and characterized MPCs by mixing a tri-magnesium phosphate powder with a solution of di-ammonium hydrogen phosphate, so to form struvite as a final setting product. The powder to liquid ratio and the concentration of the aqueous solution were systematically varied, and their effect on the properties of the final product was studied. The handling properties of the pastes were investigated, as well as the crystallinity and the microstructure; the porosity and compressive strength of the final materials were also assessed. The multi-technique approach allowed us to relate the amount of formed struvite with the properties of the material, and to identify the preparation conditions to be used to obtain a cement with desired features.