Functionalized BaTiO3 enhances piezoelectric effect towards cell response of bone scaffold

Piezoelectric effect of polyvinylidene fluoride (PVDF) plays a crucial role in restoring the endogenous electrical microenvironment of bone tissue, whereas more beta phase in PVDF leads to higher piezoelectric performance. Nanoparticles can induce the nucleation of the beta phase. However, they are prone to aggregate in PVDF matrix, resulting in weakened nucleation ability of beta phase. In this work, the hydroxylated BaTiO3 nanoparticles were functionalized with polydopamine to promote their dispersion in PVDF scaffolds fabricated via selective laser sintering. On one hand, the catechol groups of polydopamine could form hydrogen bonding with the hydroxyl groups of the BaTiO3. On the other hand, the amino groups of polydopamine were able to bond with C-F group of PVDF. As a result, the functionalized BaTiO3 nanoparticles homogeneously distributed in PVDF matrix, which significantly increased the beta phase fraction from 46% to 59% with an enhanced output voltage by 356%. Cell testing confirmed the enhanced surface electric cues significantly promoted cell adhesion, proliferation and differentiation. Furthermore, the scaffolds exhibited enhanced tensile strength and modulus, which was ascribed to the rigid particle strengthening effect and the improved interfacial adhesion. This study suggested that the piezoelectric scaffolds shown a potential application in bone repair.