Enhancing osteogenic differentiation of BMSCs on high magnetoelectric response films

High performance of biomaterial surfaces provides a sound basis to mediate cellular growth behavior. In this work, we attempted to incorporate both positive and negative magnetostriction particles of CoFe₂O₄ (CFO) and Tb_xDy_1-xFe₂ alloy (TD) into piezoelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) for forming high magnetoelectric effect films, on which osteogenic differentiation could be dynamically mediated by a magnetic-field-induced surface potential (φ_ME).The negatively poled film with TD/CFO volume ratio of 1:4 (1T4C) showed a highest magnetoelectric effect with φ_ME of -171 mV at 2800 Oe. Compared with CFO/P(VDF-TrFE) and TD/P(VDF-TrFE) films, the φ_ME increased about 213% and 173%, respectively. This could result from that P(VDF-TrFE) dipole domains receive a larger off-axial stress caused by the distribution characteristic of CFO and TD in P(VDF-TrFE), consequently to facilitate P(VDF-TrFE) dipole domain rearrangement. When MSCs were cultured on 1T4C film for 7 or 14 days, the magnetic actuation was setup to begin at the 4th or 8th day after the culture. The 7-day osteogenic differentiation was hardly affected for magnetic actuation at 4th day, moreover, the 14-day differentiation was significantly enhanced for magnetic actuation at 8th day. The enhancement appears just at a relatively late period of the cell growth, probably because the cells need a steady change in cell membrane potential to disassociate pairs of β-catenin and E-cadherin and activate osteogenic-related signaling pathway. This work could provide an alternative way to promote performance for magnetoelectric materials, and get insight into understanding of interactions of surface potential with cells.