【摘要】 磁场一直以来都被认为对骨生长具有促进作用.磁性纳米颗粒可以被看作是一个磁偶极子,因此宏观的磁性纳米颗粒组装膜也可能对附近的物体具有磁效应.本文通过层层自组装方法在聚乳酸支架表面制备了宏观γ-Fe₂O₃纳米颗粒组装膜,研究了γ-Fe₂O₃纳米颗粒组装膜对原代小鼠骨髓细胞的磁作用.原代小鼠骨髓细胞从小鼠体内新鲜提取,并在前述生物材料表面培养.定量PCR用来定量表征细胞效应,磁场的影响通过检测一种刚刚发现的磁感应蛋白来指示.结果表明,表面纳米颗粒组装可以显著增强聚合物支架的力学性质,促进细胞生长和分化.磁感应蛋白检测结果表明这是由于磁性纳米颗粒组装导致的磁效应引起的.本文用磁感应蛋白证明了磁性纳米颗粒层层自组装膜可以通过对细胞的磁效应促进干细胞的生长和分化,该磁性纳米颗粒组装膜将会促进新一代组织工程支架的研发,有可能将物理刺激效应引入到体内局部组织修复中.更多还原

【Abstract】 Magnetic field has been considered to have positive effect on growth of bone.Because a magnetic nanopartide can be regarded as one magnetic dipole,the macroscopic assemblies of magnetic nanoparticles may exhibit magnetic effect on local objects.This paper fabricated macroscopic film of γ-Fe₂O₃ nanoparticles by layer-by-layer（LBL） assembly on poly-D,L-lactic acid（PLA） scaffold,and studied the magnetic effect of the assembled γ-Fe₂O₃ nanoparticles film on primary bone marrow cells.The primary bone marrow cells were extracted from a mouse and cultured on the PLA substrate decorated by the film of γ-Fe₂O₃ nanoparticles after purification.Quantitative PCR（q-PCR） was used to show the cellular effect quantitatively.A just-found magnetosensing protein was employed to verify the magnetic effect of assembled film of nanoparticles on primary cells.It was exhibited that the decoration of nanoparticles enhanced the mechanical property of the interface.By acting as the adhesion sites,the LBL-assembled film of nanoparticles seemed beneficial to the cellular growth and differentiation.The expression of magnetosensing protein indicated that there was magnetic effect on the cells which resulted from the assembly of magnetic nanoparticles,implying its potential as a promising interface on scaffold which can integrate the physical effect with good biocompatibility to enhance the growth and differentiation of stem cells.The LBL-assembled film of magnetic nanoparticles may boost the development of novel scaffold which can introduce the physical stimulus into local tissue in vivo.更多还原