Multifunctional Sr- and Ce-substituted BaTiO3 piezoelectric pellets as orthopaedic scaffolds

Piezoelectric biomaterials that imitate human bone’s intrinsic electromechanical capabilities represent a viable approach for tissue engineering scaffolds. Comprehensive structural and functional investigations show that the addition of strontium (Sr) and cerium (Ce) dopants to barium titanate (BaTiO₃) lattice greatly improves its biocompatibility for orthopaedic applications. X-ray diffraction (XRD) and Raman spectroscopy confirmed the retention of the tetragonal phase ( P4mm ) in doped samples, with reduced tetragonality (c/a ratio) and stable vibrational modes at ∼250–720 cm⁻¹. Field-emission scanning electron microscopy (FESEM) revealed changes in the average grain size with Sr and Ce doping, while energy-dispersive spectroscopy (EDS) verified homogeneous Sr/Ce distribution. The doped samples exhibit commendable piezoelectric coefficients (d 33 ) ranging from 8-25 pC/N and 18-23 pC/N for Sr- and Ce-doped samples, respectively, which is higher than the d 33 value of human bone. The density, open porosity, and water absorption properties of the pellet scaffolds were examined, and the 3 mol% Sr- and Ce- doped BT pellets exhibited values in the optimal range. The antibacterial studies against E. coli and S. aureus suggested that all the pellet scaffolds have antibacterial properties against both gram-negative and gram-positive bacteria, with the Ce-doped sample exhibiting the best performance. In-vitro MTT assay and AO-EB staining showed >90% MG-63 viability at 7 days for doped samples (vs. 85% for BaTiO₃), with 3 mol% doping showing the best biocompatibility.