Lead-Free Piezoelectric (Ba,Ca)(Zr,Ti)O₃ Thin Films for Biocompatible and Flexible Devices

In this work, we report the synthesis of functional biocompatible piezoelectric (1 - x)Ba(Ti_0.8Zr_0.2)TiO₃-x(Ba_0.7Ca_0.3)TiO₃, x = 0.45 (BCZT45), thin films with high piezoelectric properties. Pulsed-laser-based techniques, classical pulsed-laser deposition and matrix-assisted pulsed-laser evaporation, were used to synthesize the BCZT45 thin films. The second technique was employed in order to ensure growth on polymer flexible Kapton substrates. The BCZT45 thin films grown by both techniques show similar structural properties and high piezoelectric coefficient coupling between the mechanical loading and electrical potential. While it has long been shown that the electrical potential favors biological processes like osteogenesis, the assessment of cell adhesion and osteogenic differentiation onto BCZT materials has not yet been demonstrated. We prove here for the first time that BCZT 45 coatings on Kapton polymer substrates provide optimal support for osteogenic differentiation of mesenchymal stem cells in the bone marrow.