Intelligent and Bioactive Osseointegration of the Implanted Piezoelectric Bone Cement with the Host Bone Is Realized by Biomechanical Energy

Poly methyl methacrylate (PMMA) bone cement is widely used in orthopedic surgeries, including total hip/knee arthroplasty and vertebral compression fracture treatment. However, loosening due to bone resorption is a common mid-to-late complication. Therefore, developing bioactive bone cement that promotes bone growth and integration is key to reducing aseptic loosening. In this study, we developed a piezoelectric bone cement comprising PMMA and BaTiO3 with excellent electrobioactivity and further analyzed its ability to promote bone integration. Experiments demonstrate that the PMMA and 15 wt % BaTiO3 cement generated an open-circuit voltage of 37.109 V under biomimetic mechanical stress, which effectively promoted bone regeneration and interfacial bone integration. In vitro experiments showed that the protein expression levels of ALP and RUNX-2 in the 0.65 Hz and 20 min group increased by 1.74 times and 2.31 times. In vivo experiments confirmed the osteogenic ability of PMMA and 15 wt % BaTiO3, with the increment of bone growth in the non-movement and movement groups being 4.67 and 4.64 times, respectively, at the second month after surgery. Additionally, Fluo-4 AM fluorescence staining and protein blotting experiments verified that PMMA and 15 wt % BaTiO3 electrical stimulation promoted osteogenic differentiation of BMSCs by activating calcium-sensitive receptors and increasing calcium ion inflow by 1.41 times when the stimulation reached 30 min. Therefore, piezoelectric bioactive PMMA and 15 wt % BaTiO3 cement has excellent application value in orthopedic surgery systems where stress transmission is prevalent.