磁性纳米粒子诱导DNA取向的AFM成像研究
发布时间：2019-04-04 13:36
【摘要】：双链DNA分子是一种具有一定链柔性的生物大分子，在生物医学及DNA纳米技术等诸多领域均有广泛的应用。原子力显微镜具有原子级的成像分辨率，操作简单，使用范围广等优点常被用来研究DNA与其它一些分子的相互作用及结合模式，给出单分子水平上的信息。但是由于长链DNA倾向于以卷曲的构象存在，阻碍了利用AFM扫描来直接进行观测，掩盖了一些重要的信息。因此利用外场操纵DNA分子使其伸展取向，不仅有利于研究DNA与其它分子的结合机理，而且可以为DNA纳米技术奠定基础。 本论文中首先采用高温热分解法以乙酰丙酮铁为铁源制备了油胺油酸修饰的哑铃状的5.5-10nm Au-Fe3O4纳米粒子，，并以mPEG-COOH为配体转移剂将油相纳米粒子成功地转移到水相。通过透射电子显微镜(TEM)、紫外分光光度计(UV-vis)、傅里叶红外光谱仪(FTIR)、X-射线粉末衍射仪(XRD)、动态光散射仪(DLS)、振动样品磁强计(VSM)对纳米粒子转移前后的性质进行了表征。结果显示，水相转移后的纳米粒子在形貌大小上无明显变化，Au-Fe3O4纳米粒子在水溶液中具有良好的分散性，表面带正电荷，室温下具有超顺磁性。经表面改性后的Au-Fe3O4能够用于与双链DNA分子的偶联反应。随后，利用PCR扩增技术合成了5‘端分别修饰有氨基和巯基的双链DNA分子(2000bp)，通过Au-S化学键作用将DNA固定到纳米粒子Au表面，另一端通过氨基固定到NHS活化的氨基化的硅片表面。并利用AFM成像技术对磁场作用下DNA分子的诱导取向伸展进行了研究，结果表明，通过外加磁场控制磁性纳米粒子的运动能够使DNA伸展取向，且在撤去磁场的情况下经过润洗DNA可以恢复到无规状态，从而可通过控制外加磁场实现对DNA分子的可控诱导取向。
[Abstract]:Double-stranded DNA is a kind of biomacromolecule with certain chain flexibility. It has been widely used in many fields such as biomedicine and DNA nanotechnology. Atomic force microscopy (AFM) has the advantages of atomic-level imaging resolution, simple operation and wide application range. It is often used to study the interaction and binding modes of DNA with other molecules, and to give the information at the level of single molecule. However, due to the tendency of long-chain DNA to exist in conformational curl, it hinders the use of AFM scanning to directly observe and mask some important information. Therefore, it is not only beneficial to study the binding mechanism of DNA with other molecules, but also to lay a foundation for DNA nanotechnology by using external field to manipulate the stretching orientation of DNA molecules. In this thesis, the dumbbell-like 5.5-10nm Au-Fe3O4 nanoparticles modified by oleate oleic acid were prepared by high temperature thermal decomposition using iron acetylpyruvate as Tie Yuan. The mPEG-COOH was used as ligand transfer agent to transfer the oil nanoparticles to aqueous phase successfully. Transmission electron microscope (TEM), ultraviolet spectrophotometer (UV-vis), Fourier infrared spectrometer (FTIR), X-ray powder diffractometer (XRD), dynamic light scattering instrument (DLS), The properties of nano-particles before and after transfer were characterized by vibrating sample magnetometer (VSM). The results show that there is no obvious change in the morphology of the nano-particles after water phase transfer. The Au-Fe3O4 nanoparticles have good dispersion in aqueous solution with positive charge on the surface and superparamagnetism at room temperature. The surface modified Au-Fe3O4 can be used for coupling reaction with double-stranded DNA molecules. Subsequently, double-stranded DNA (2000bp) with amino and sulfhydryl groups modified by 5'- terminal was synthesized by PCR amplification technique, and DNA was immobilized on the surface of Au nanoparticles by Au-S chemical bonding. The other end is immobilized on the surface of the NHS-activated amino-activated silicon wafer by amino-immobilization. The AFM imaging technique was used to study the induced orientation extension of DNA molecules under magnetic field. The results show that the orientation of DNA can be controlled by external magnetic field control of the magnetic nanoparticles. When the magnetic field is removed, the wetted DNA can be restored to the random state, thus the controllable orientation of DNA molecules can be achieved by controlling the external magnetic field.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
本文编号：2453867
[Abstract]:Double-stranded DNA is a kind of biomacromolecule with certain chain flexibility. It has been widely used in many fields such as biomedicine and DNA nanotechnology. Atomic force microscopy (AFM) has the advantages of atomic-level imaging resolution, simple operation and wide application range. It is often used to study the interaction and binding modes of DNA with other molecules, and to give the information at the level of single molecule. However, due to the tendency of long-chain DNA to exist in conformational curl, it hinders the use of AFM scanning to directly observe and mask some important information. Therefore, it is not only beneficial to study the binding mechanism of DNA with other molecules, but also to lay a foundation for DNA nanotechnology by using external field to manipulate the stretching orientation of DNA molecules. In this thesis, the dumbbell-like 5.5-10nm Au-Fe3O4 nanoparticles modified by oleate oleic acid were prepared by high temperature thermal decomposition using iron acetylpyruvate as Tie Yuan. The mPEG-COOH was used as ligand transfer agent to transfer the oil nanoparticles to aqueous phase successfully. Transmission electron microscope (TEM), ultraviolet spectrophotometer (UV-vis), Fourier infrared spectrometer (FTIR), X-ray powder diffractometer (XRD), dynamic light scattering instrument (DLS), The properties of nano-particles before and after transfer were characterized by vibrating sample magnetometer (VSM). The results show that there is no obvious change in the morphology of the nano-particles after water phase transfer. The Au-Fe3O4 nanoparticles have good dispersion in aqueous solution with positive charge on the surface and superparamagnetism at room temperature. The surface modified Au-Fe3O4 can be used for coupling reaction with double-stranded DNA molecules. Subsequently, double-stranded DNA (2000bp) with amino and sulfhydryl groups modified by 5'- terminal was synthesized by PCR amplification technique, and DNA was immobilized on the surface of Au nanoparticles by Au-S chemical bonding. The other end is immobilized on the surface of the NHS-activated amino-activated silicon wafer by amino-immobilization. The AFM imaging technique was used to study the induced orientation extension of DNA molecules under magnetic field. The results show that the orientation of DNA can be controlled by external magnetic field control of the magnetic nanoparticles. When the magnetic field is removed, the wetted DNA can be restored to the random state, thus the controllable orientation of DNA molecules can be achieved by controlling the external magnetic field.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
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相关期刊论文 前2条
1 张鑫;李鑫钢;姜斌;;四氧化三铁纳米粒子合成及表征[J];化学工业与工程;2006年01期
2 刘飞;朱静菡;侯仰龙;高松;;Chemical synthesis of magnetic nanocrystals:Recent progress[J];Chinese Physics B;2013年10期
本文编号：2453867
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