SCENCNNEWS www.advancedsciencenews.com 10wt% RGD d The range of v o Immersion with DC magnetic field o Immersion without DC magnetic field steoinductive surface 士壬 MD simulation and characterization of the CFO/P(VDF-TrFE) magnetoelectric nanocomposite membrane a) Snapshots of the simulations, showing that the RGD site was oriented towards the solution phas he 10 wt% CFO/P(VDF-TrF )SEM images of 10 wt% CFO/P(VDF-TrFE)membranes. c)The magnetic-field-induced surface potential of CFO/P(VDF- TrFE)me ferent CFO content. Vr ctrical communication-endogenous voltage gradients across the plasma membrane. ( Typical nv). 4al d) Zeta potential of 10 wt% CFO/P(VDF- TrFE)membranes without immersion and membranes immersed in culture mediu exposure to a remote DC magnetic field after 1, 7, 14 days increased FN adsorption which lead to increased RGD expo. CFO nanoparticles content(Figure S2e, Supporting Informa- ure can facilitate integrin binding to enhance focal adhesion tion). In hysteresis loop tests, the maximum magnetization (FA) formation and effect MSC and macrophage responses to value of the different composite membranes was approximately biomaterials. 16. 4 These MD simulations predict that the mag. proportional to the amount of CFO nanoparticles within the matrix( Figure S2f, Supporting Information).The netoelectric microenvironment provided by 10 wt% CFO con- P(VDF-TrE y 594 9 tent composite membranes could induce optimal biological magnetoelectric effect of the nanocomposite membranes is fte due to an elastic coupling interaction between electrical polari- zation and particle concentration within the co-polymer 2.2. Characterizing the Magnetoelectric Microenvironment matrix might favor arrangement of polar conformations and Provided by the CFO/P(VDF-TrFE)Nanocomposite Membranes therefore lead to enhanced ferroelectric and piezoelectric responses. 2 Based on the MD simulation, the CFO/P(VDF-TrFE)magneto. We next evaluated the magnetoelectric effects of membranes. electric nanocomposite membranes with different CFO nano- The magnetoelectric effect, defined as the variation of the elec- article contents(5, 10, 15, 20 wt%)( Figure S2a, Supporting trical polarization of a material in the presence of an applied Information) were fabricated. Scanning electron microscope magnetic field, or as the induced magnetization in the presence (SEM) imaging revealed extensive agglomeration of CFo of an applied electric field, can be seen as a bridge between anoparticles at contents >15 wt%( Figure 2b; Figure S2b, the electric and magnetic properties of matter. I The results upporting Information). Homogenous dispersion of CFo demonstrated that 10 wt% CFO content membranes exhib- anoparticles within the piezoelectric matrix is a key prereg. ited the largest range of magnetic-field-induced surface poten- isite for achieving a significant magnetoelectric effect 25) tial(Figure 2c) among all groups after corona poling at room With increasing content of CFO nanoparticles, the content of temperature. The magnetic-field-induced surface potential of the B-phase within the P(VDF-TrFE) matrix decreases, as evi- 10 wt% CFO content membranes could be tuned from0 to denced by Fourier transform infrared spectroscopy imaging 91.15 mv by increasing the remote DC magnetic field from (Figure S2c, Supporting Information) and X-ray diffraction 0 to 3000 Oe. Our preliminary results showed that the surface patterns(Figure S2d, Supporting Information). The B-phase potential of around 54 mV is most favorable for osteogenesis 126 is closely correlated with piezoelectric properties, as it is an However, the retention period of the surface potential induced electrically active phase. 26 Consistent with the B-phase data, by piezoelectric materials is not sufficient for optimal osteo- the piezoelectric coefficients (d33) decreased with increasing genesis. For the magnetoelectric composites, the surface Adw. Funct Mater. 2020. 2006226 20062264of) g 2020 Wiley-VCH GmbHwww.advancedsciencenews.com www.afm-journal.de 2006226 (4 of 11) © 2020 Wiley-VCH GmbH increased FN adsorption which lead to increased RGD expo￾sure can facilitate integrin binding to enhance focal adhesion (FA) formation and effect MSC and macrophage responses to biomaterials.[16,24] These MD simulations predict that the mag￾netoelectric microenvironment provided by 10 wt% CFO con￾tent composite membranes could induce optimal biological effects. 2.2. Characterizing the Magnetoelectric Microenvironment Provided by the CFO/P(VDF-TrFE) Nanocomposite Membranes Based on the MD simulation, the CFO/P(VDF-TrFE) magneto￾electric nanocomposite membranes with different CFO nano￾particle contents (5, 10, 15, 20 wt%) (Figure S2a, Supporting Information) were fabricated. Scanning electron microscope (SEM) imaging revealed extensive agglomeration of CFO nanoparticles at contents >15  wt% (Figure  2b; Figure S2b, Supporting Information). Homogenous dispersion of CFO nanoparticles within the piezoelectric matrix is a key prereq￾uisite for achieving a significant magnetoelectric effect.[25] With increasing content of CFO nanoparticles, the content of the β-phase within the P(VDF-TrFE) matrix decreases, as evi￾denced by Fourier transform infrared spectroscopy imaging (Figure S2c, Supporting Information) and X-ray diffraction patterns (Figure S2d, Supporting Information). The β-phase is closely correlated with piezoelectric properties, as it is an electrically active phase.[26] Consistent with the β-phase data, the piezoelectric coefficients (d33) decreased with increasing CFO nanoparticles content (Figure S2e, Supporting Informa￾tion). In hysteresis loop tests, the maximum magnetization value of the different composite membranes was approximately proportional to the amount of CFO nanoparticles within the P(VDF-TrFE) matrix (Figure S2f, Supporting Information). The magnetoelectric effect of the nanocomposite membranes is due to an elastic coupling interaction between electrical polari￾zation and magnetostrictive components.[27] Hence, appro￾priate CFO nanoparticle concentration within the co-polymer matrix might favor arrangement of polar conformations and therefore lead to enhanced ferroelectric and piezoelectric responses.[28] We next evaluated the magnetoelectric effects of membranes. The magnetoelectric effect, defined as the variation of the elec￾trical polarization of a material in the presence of an applied magnetic field, or as the induced magnetization in the presence of an applied electric field, can be seen as a bridge between the electric and magnetic properties of matter.[11] The results demonstrated that 10 wt% CFO content membranes exhib￾ited the largest range of magnetic-field-induced surface poten￾tial (Figure  2c) among all groups after corona poling at room temperature. The magnetic-field-induced surface potential of 10 wt% CFO content membranes could be tuned from 0 to 91.15  mV by increasing the remote DC magnetic field from 0 to 3000 Oe. Our preliminary results showed that the surface potential of around 54 mV is most favorable for osteogenesis.[26] However, the retention period of the surface potential induced by piezoelectric materials is not sufficient for optimal osteo￾genesis.[13] For the magnetoelectric composites, the surface Figure 2. MD simulation and characterization of the CFO/P(VDF-TrFE) magnetoelectric nanocomposite membrane a) Snapshots of the molecular dynamic simulations, showing that the RGD site was oriented towards the solution phase on the 10 wt% CFO/P(VDF-TrFE) magnetoelectric mem￾brane. b) SEM images of 10 wt% CFO/P(VDF-TrFE) membranes. c) The magnetic-field-induced surface potential of CFO/P(VDF-TrFE) membranes with different CFO content. Vmem: Bioelectrical communication-endogenous voltage gradients across the plasma membrane. (Typical value: −60 to −100 mV).[48] d) Zeta potential of 10 wt% CFO/P(VDF-TrFE) membranes without immersion and membranes immersed in culture medium with or without exposure to a remote DC magnetic field after 1, 7, 14 days. Adv. Funct. Mater. 2020, 2006226