Improving bone regeneration with composites consisting of piezoelectric poly(l-lactide) and piezoelectric calcium/manganese co-doped barium titanate nanofibers

The reconstruction of the local electrical microenvironment at the defect site has been considered as an effective strategy in stimulating bone regeneration. To mimic the electrophysiological nature of native bone tissue, piezoelectric ceramics and polymers are widely used as scaffolding materials. Herein, novel piezoelectric Ca/Mn co-doped BaTiO3 (CMBT) nanofibers were composited with poly(l-lactide) (PLLA), to obtain a kind of substrates with strengthened piezoelectricity after polarization. Compared to pure BaTiO3 nanofibers, the CMBT nanofibers exhibited extra osteogenic activity with the incorporation of bioactive Ca/Mn elements in addition to their piezoelectric property. Compared to non-degradable piezoelectric polymers like poly(vinylidene fluoride) (PVDF), polarized PLLA is not only biodegradable, but also piezoelectric. Therefore, as the CMBT nanofibers forming a network within the PLLA matrix, the PLLA/CMBT composites could significantly improve osteogenic activity both in vitro and in vivo. Using non-piezoelectric polycaprolactone (PCL) and polarized PLLA as controls, the strong antibacterial and anti-inflammatory activities of piezoelectric PLLA/CMBT composites were also identified, providing additional benefits for bone repairing. In summary, the polarized PLLA/CMBT composites are promising candidates for bone regeneration and function reconstruction, due to their multi-functionality in terms of electroactivity, biodegradability, antibacterial and anti-inflammatory activities, to meet the challenged requirements in inducing osteogenesis.