ln vitro assessment of immunomodulatory and osteogenic properties in 3D-printed hydroxyapatite/barium titanate piezoelectric ceramic scaffolds

Research has demonstrated a significant correlation between the skeletal and immune systems. Moreover, piezoelectric materials can affect macrophage polarization, thereby enhancing osteogenic differentiation in stem cells. This study involved the preparation of a piezoelectric ceramic scaffold, comprising hydroxyapatite (HA) and barium titanate (BT), using digital light processing (DLP) 3D printing technology. The scaffold's mechanical (compressive strength: 145.5 MPa) and piezoelectric (d33: 2.15 pC N−1) properties closely resemble those of cortical bone. In vitro analyses revealed that the polarized HA/BT ceramic samples are biologically safe and can induce macrophage polarization towards the M2 phenotype (anti-inflammatory), as well as enhance osteogenic differentiation in dental pulp stem cells (DPSCs) when stimulated with low-intensity pulsed ultrasound (LIPUS). In summary, our findings suggest that 3D printed HA/BT piezoelectric ceramic scaffolds, when stimulated by LIPUS, hold significant potential for application in bone tissue engineering, and further research is needed to investigate the performance in bone defect animal models.