Polydopamine/Montmorillonite-Based Brushite Calcium Phosphate Cements: Synergize Mechanical and Osteogenic Capacity for Bone Regeneration

Although brushite calcium phosphate cements (Bru-CPCs) possess good bioactivity and biocompatibility, their low compressive strength hinders their effective application in osteoporotic bone defect treatment. Therefore, the aim of this study was to improve the compressive strength without sacrificing the osteogenesis properties of Bru-CPCs. Montmorillonite (MMT) was added into Bru-CPCs to get Bru-CPCs/1.5% MMT. The compressive strength of Bru-CPCs/1.5% MMT increased to 13.31 MPa, but the interfacial interactions between MMT and Bru-CPCs (inorganic-inorganic phase) limited further improvement in compressive strength. Inspired by the adhesive proteins in mussels, MMT was coated with a polydopamine (PDA) layer to get MMT@PDA. The compressive strength of Bru-CPCs/1.5% MMT@PDA further increased to 16.58 MPa. Then, the surface morphology, adhesiveness, biocompatibility, and bioactivity of CPCs/1.5% MMT@PDA were evaluated. All data indicated that by adding MMT@PDA, the compressive strength was improved without sacrificing the osteogenesis properties of Bru-CPCs.