Design of novel organic-inorganic composite bone cements with high compressive strength, in vitro bioactivity and...

In this work, novel bioactive organic-inorganic composite bone cements consisting of tricalcium silicate (C₃ S), sodium alginate (SA), and calcium sulfate hemihydrate (CS) were successfully fabricated for the first time via a special method designing material composition and internal structure simultaneously, which was intended to enhance mechanical performance by combining progressive hydration process of C₃ S with distinctive gelation capacity of SA and further improve degradability and self-setting properties with the addition of CS. Depending on the synergistic combination of hydration and gelation, the C₃ S/SA/CS composite cements (45/45/10 wt %) obtained extremely higher compressive strength up to 92.41 MPa as compared with each single component. The reinforcing mechanisms involving interfacial interaction and interior microstructure were proposed to explain this enhancement phenomenon. Additionally, the final setting time could be reduced from 68 min to 21 min with the increasing CS content. The composite cements possessed good apatite mineralization ability in simulated body fluid solution and moderate degradation rate in phosphate buffer solution. What's more, the composite cements exhibited excellent cytocompatibility and increased proliferation of rat bone-marrow stem cells. This study could provide guidelines for the preparation of bioactive composite cements with enhanced mechanical performance, which may be suitable for load-bearing bone repair. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2365-2377, 2019.