In situ magnesium calcium phosphate cements formation: From one pot powders precursors synthesis to in vitro investigations

• Published in: Bioactive materials Vol. 5; no. 3; pp. 644 - 658
• Main Authors: Goldberg, M.A., Krohicheva, P.A., Fomin, A.S., Khairutdinova, D.R., Antonova, O.S., Baikin, A.S., Smirnov, V.V., Fomina, A.A., Leonov, A.V., Mikheev, I.V., Sergeeva, N.S., Akhmedova, S.A., Barinov, S.M., Komlev, V.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2020; KeAi Communications Co., Ltd
• Subjects: Brushite; In vitro investigations; Magnesium calcium phosphate cement; Newberyite; Stanfieldite; Whitlockite; Brushite; Stanfieldite; Whitlockite; Magnesium calcium phosphate cement; Newberyite; In vitro investigations
• ISSN: 2452-199X; 2452-199X
• DOI: 10.1016/j.bioactmat.2020.03.011

Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate. Struvite (MgNH4PO4) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH4+ ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9–10, leading to cytotoxicity.
Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na2HPO4-based cement liquid. For this purpose, cement powders precursors in the CaO–MgO–P2O5 system were synthesized by one-pot process in a wide composition range, and their properties were investigated.
The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.
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•Self-setting magnesium-calcium phosphate cements were synthesized by one-pot processes.•Cement liquid based on NaH2PO4 warrantee the absence of ammonia release in human body.•New regularity between (Ca + Mg)/P ratio and bone cements phase formation with NaH2PO4 were established.•The optimal ratio of (Ca + Mg)/P = 1.67 resulted in neutral pH and sufficient strength.