【摘要】：雙鏈DNA分子是一種具有一定鏈柔性的生物大分子，在生物醫(yī)學(xué)及DNA納米技術(shù)等諸多領(lǐng)域均有廣泛的應(yīng)用。原子力顯微鏡具有原子級(jí)的成像分辨率，操作簡(jiǎn)單，使用范圍廣等優(yōu)點(diǎn)常被用來(lái)研究DNA與其它一些分子的相互作用及結(jié)合模式，給出單分子水平上的信息。但是由于長(zhǎng)鏈DNA傾向于以卷曲的構(gòu)象存在，阻礙了利用AFM掃描來(lái)直接進(jìn)行觀測(cè)，掩蓋了一些重要的信息。因此利用外場(chǎng)操縱DNA分子使其伸展取向，不僅有利于研究DNA與其它分子的結(jié)合機(jī)理，而且可以為DNA納米技術(shù)奠定基礎(chǔ)。 本論文中首先采用高溫?zé)岱纸夥ㄒ砸阴１F為鐵源制備了油胺油酸修飾的啞鈴狀的5.5-10nm Au-Fe3O4納米粒子，，并以mPEG-COOH為配體轉(zhuǎn)移劑將油相納米粒子成功地轉(zhuǎn)移到水相。通過(guò)透射電子顯微鏡(TEM)、紫外分光光度計(jì)(UV-vis)、傅里葉紅外光譜儀(FTIR)、X-射線粉末衍射儀(XRD)、動(dòng)態(tài)光散射儀(DLS)、振動(dòng)樣品磁強(qiáng)計(jì)(VSM)對(duì)納米粒子轉(zhuǎn)移前后的性質(zhì)進(jìn)行了表征。結(jié)果顯示，水相轉(zhuǎn)移后的納米粒子在形貌大小上無(wú)明顯變化，Au-Fe3O4納米粒子在水溶液中具有良好的分散性，表面帶正電荷，室溫下具有超順磁性。經(jīng)表面改性后的Au-Fe3O4能夠用于與雙鏈DNA分子的偶聯(lián)反應(yīng)。隨后，利用PCR擴(kuò)增技術(shù)合成了5‘端分別修飾有氨基和巰基的雙鏈DNA分子(2000bp)，通過(guò)Au-S化學(xué)鍵作用將DNA固定到納米粒子Au表面，另一端通過(guò)氨基固定到NHS活化的氨基化的硅片表面。并利用AFM成像技術(shù)對(duì)磁場(chǎng)作用下DNA分子的誘導(dǎo)取向伸展進(jìn)行了研究，結(jié)果表明，通過(guò)外加磁場(chǎng)控制磁性納米粒子的運(yùn)動(dòng)能夠使DNA伸展取向，且在撤去磁場(chǎng)的情況下經(jīng)過(guò)潤(rùn)洗DNA可以恢復(fù)到無(wú)規(guī)狀態(tài)，從而可通過(guò)控制外加磁場(chǎng)實(shí)現(xiàn)對(duì)DNA分子的可控誘導(dǎo)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.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TB383.1

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相關(guān)期刊論文 前2條

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