Preparation and characterization of novel lithium magnesium phosphate bioceramic scaffolds facilitating bone generation

Both magnesium and lithium are able to stimulate osteogenic and angiogenic activities. In this study, lithium magnesium phosphate (Li0.5Mg2.75(PO4)2, Li1Mg2.5(PO4)2 and Li2Mg2(PO4)2) biomaterials were synthesized by a solid-state reaction method, and their bioceramic blocks and scaffolds were fabricated by compression molding and 3D printing, respectively. The results indicated that the lithium magnesium phosphates consisted of the Mg3(PO4)2 phase and/or LiMgPO4 phase. Compared with the lithium-free Mg3(PO4)2 bioceramics, the lithium magnesium phosphate bioceramics showed a lower porosity and consequently a higher compressive strength, and stimulated in vitro cellular proliferation, osteogenic differentiation and proangiogenic activity. In vivo results manifested that the Li2Mg2(PO4)2 bioceramic scaffolds efficiently promoted bone regeneration of critical-size calvarial defects in rats. Benefiting from the high compressive strength and capacity of stimulating osteogenesis and angiogenesis, the Li2Mg2(PO4)2 bioceramic scaffolds are considered promising for efficiently repairing the bone defects.