The Preparation Of Terfenol-D/P(DVF-TrFE)Magnetoelectric Film And Its Modulation Of Osteogenic Differentiation Behavior Of MSCs

The surface properties of materials play an important role in the interaction of biological materials with cells,while the surface potential exhibits the ability to effectively modulate cell growth behavior.However,there are often conflicting reports on the effects of positive and negative potentials on cell behavior.In this study,we constructed a positive or negative potential surface with the same composition and morphology that can produce a wide variation of the surface potential.The regulatory effect and mechanism of the surface potential on the osteoblastic differentiation of stem cells were investigated in depth,to provide theoretical guidance for the design of implant surface with high osteoblastic ability.This study has achieved important results in the following two aspects:1.The preparation of Terfenol-D/P(VDF-TrFE)magnetoelectric film and construction of the surface potentialTerfenol-D/P(VDF-TrFE)magnetoelectric films were prepared on a titanium substrate by Casting molding using magnetostrictive TbxDy1-xFe2 alloy(Terfenol-D)and piezoelectric polymer(P(VDF-TrFE)),and the polarization mode was used to produce a positive or negative surface potential.The magnetoelectric coupling properties of the films were optimized by changing the heat-treatment temperature,Terfenol-D addition content and particle size.Finally,under the driving of 0?3200 Oe magnetic field,the same film can produce a wide variation of the surface potential(?EM)in the range of 0?+120 or 0?-120 mV.2.The effect of surface potential on osteoblast differentiation and its mechanismBoth positive and negative potential surfaces can effectively promote the osteogenic differentiation of mesenchymal stem cells(MSCs).With the increase of/?EM/,the differentiation ability of MSCs was parabolic.The difference between the positive and negative potential surfaces is that:at low/?EM/(0?35 mV),the ability of the negative potential surface promotiing bone differentiation was better,while the high/?EM/(35?55 mV),the positive potential surface can promote bone differentiation better.The RGD and PHSRN functional site exposure of FN on the negative potential surface was always higher than that on the positive potential surface,and the exposure on the two surfaces showed the same change behavior with/?EM/;However,on the positive potential surface,the expression of integrin ?5?1 of MSCs was different from that in FN adsorption,and the expression was higher than the negative potential surface at high/?EM/;Either on the positive or negative potential surface,when the expression of cellular integrin ?5?1 was the largest,the osteogenic differentiation-related signaling pathway FAK/ERK and osteogenic differentiation ability also reached the maximum,indicating that the MSCs osteogenic differentiation was integrin-mediated in this study.Combined with the adsorption state of FN protein and the changing behavior of integrin expression,as well as the previous analysis of FN,we proposed the mechanism for the difference of osteogenic differentiation on the positive and negative potential surface:the spatial distribution and law of change with potential of the exposure sites RGD and PHSRN are different,resulting in different binding strength to the cell integrin ?5?1 which ultimately leads to differences in integrin-mediated cell differentiation.The results of our study also indicated that in the comparative study of the positive and negative surface potential effects,the absolute value of the surface potential will directly affect the comparison of the positive and negative surface potentials.