Formation and properties of magnesium–ammonium–phosphate hexahydrate biocements in the Ca–Mg–PO4 system
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Calcium substituted trimagnesium phosphate with the general formula CaxMg(3−x)(PO4)2 (0 < x < 1.5) was synthesized by calcination of powder mixtures with the appropriate stoichiometry and reacted with 3.5 M diammonium hydrogenphosphate solution to form a cementitious matrix of magnesium ammonium phosphate hexahydrate (struvite). The degree of ionic substitution was shown to influence physical cement properties; clinically suitable cement formulations with setting times in the range 5–15 min and compressive strengths of >50 MPa were obtained for x ≤ 0.75 together with a grinding time ≥1 h and a powder to liquid ratio ≥2.5 g/ml. The cement cytocompatibility was investigated by culturing human osteoblast cell line MG63 on cement surfaces demonstrating pronounced cell growth during 13 days cultivation.
KeywordsCalcium Phosphate Cement Ionic Substitution Magnesium Phosphate Monetite Initial Setting Time
The authors would like to acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG Gb1/11-1 and DFG Mu1803/7-1).
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