Enhanced compressive strengths and induced cell growth of 1-3-type BaTiO₃/PMMA bio-piezoelectric composites

Barium titanate (BaTiO₃) has been used as a bone implant material because of its piezoelectric properties and the ability to promote cell growth when combined with hydroxyapatite. However, the brittleness of BaTiO₃ inhibits its use as a bone replacement material at load-bearing sites, and the reduction of BaTiO₃ content in the composite reduces its piezoelectric effect on bone growth. In this study, we explored a preparation method, which included directional freeze casting and self-solidification of bone cement, to obtain 1-3-type BaTiO₃/PMMA bio-piezoelectric composites with a lamellar structure. The lamellar BaTiO₃ layer through the composite from the bottom to the top significantly improved the piezoelectric properties of the composite. In addition, the dendritic ceramic bridges on the BaTiO₃ pore walls can improve the compressive strength and elastic modulus of BaTiO₃/PMMA bio-piezoelectric composites with a lamellar structure. More importantly, it was found that polarized lamellar BaTiO₃ could induce osteoblasts to grow in the direction of the BaTiO₃ layers. When the width of the BaTiO₃ layer was in the range of 8-21 μm, osteoblasts along the BaTiO₃ layer showed well growth, which can be of great value for the production of biomimetic bone units.