【作者】 何晓燕；

【导师】 杨武；

【作者基本信息】 西北师范大学 ， 分析化学， 2005， 硕士

【摘要】 纳米科技以现代先进科学技术为基础,是现代科学(混沌物理、量子物理、介观物理、分子生物学)和现代技术(计算机技术、微电子技术、扫描隧道显微技术、核分析技术)相结合的产物。在广博的自然界、生物界充满了纳米科学的涵义,纳米科技及分子机器实际上早已存在。动、植物按最微基准来定义,就是这些“纳米机器”的组合体。这些纳米机器中最为人熟知的就是蛋白质、核糖核酸(RNA)以及辅助细胞再生修复和辅助制造蛋白质的酶。 DNA被称为生命体内的基因物质,是生命科学中的关键分子,它不仅作为基因信息的载体有重要的研究价值,并且可能用做纳米器件的基本构成单元而引起广泛的研究兴趣。DNA分子稳定的线形结构及其一定程度上的导电性,使人们设想可用DNA分子作为分子导线连接人造和天然的纳米器件。DNA分子的操作尤其是分子拉直的方法及其生物学应用研究已成为分子操纵和控制的研究热点。原子力显微镜(Atomic force microscopy, AFM)是1986年由Binning、Ouate、Gerber在STM的基础上发展起来的另一种表征样品表面性质的有利工具,它是通过检测探针与样品接触时的微小作用力的变化来获得样品表面信息,AFM成像DNA分子可以达到很高的分辨率(<5nm),并可以在各种环境下进行操作,本文利用原子力显微镜观察了DNA分子在几种基底表面的沉积与扩展,对DNA分子链的吸附行为进行了初步研究。 通过一种简便的方法快速实现了DNA分子的沉积与扩展,利用AFM清楚观察到了扩展的DNA分子,通过DNA分子分别在硅片、云母片和修饰过的云母片上所得的AFM图像对比得出DNA在修饰过的云母片上扩展更容易,图像稳定性好,可重复性高。还用超声振荡的方法处理了DNA溶液,说明这种方法可以有效打断DNA分子。 在三氨基丙基三乙氧基硅烷(APS)的基础上,通过麦克尔加成合成了DAPS,并利用AFM对吸附了DNA分子的硅烷化的云母片表面进行观察,发现APS/云母明显比DAPS/云母粗糙,说明DAPS更适合用于修饰基底。并进一步观察了不同DAPS浓度下DNA分子的吸附行为,发现当DAPS/甲醇体积比浓度为1:100时,DNA分子呈现出大而复杂的形态,发生了分子内和分子间的碱基相互配对;当体积比浓度为1:3000时,即没有分子内和分子间的碱基相互配对,也更多还原

【Abstract】 Nano-technology is based on the modem advanced technology. It is a product integrated the modern science, which includes the chaos physics, quanta physics, meso-physics, molecular biology, and the modern technology, which includes computer technology, microelectronic technology, scanning tunnel microscope technology, nucleo-analysis technology together. The meaning of nano-science exists in the all around nature and biosphere. Actually, the nano-science and technology and the molecule machine have existed long before. If the animal and plants are defined by the tiniest benchmark, they are the combinations integrated by these nano-machines. The most well-known in these nano-machines are the protein, ribonucleic acid (RNA), and enzyme, which can assist the cell with regenesis and restoring.DNA is an attractive candidate for the study in nanoscale positioning of biological molecules because of its exquisite specificity in base pairing, ~1 nm radius combined with large aspect ratio, and ready availability. It has attracted attention as a device material in the field of nanobioelectronics on the basis of its characteristics such as self-assembly, electric conductivity and the capacity to interact with various chemicals and biomaterials. Direct physical mapping of DNA and DNA-protein complexes with atomic force microscopy (AFM) has been an attractive topic in recent years for the nanometer spatial resolution and the variety of acceptable environmental conditions (vacuum, air, liquid) afforded by AFM. Since the invention of the AFM , imaging of DNA has been one of the most eagerly anticipated applications. AFM imaging of uncoated DNA molecules has great potential for contributing to a detailed knowledge of the substructure of individual DNA molecule and the understanding of processes involving DNA. In this thesis, the deposition and extending of double-strand DNA on several kinds of surfaces were observed by AFM.The deposition and extending of double-strand DNA on three kinds of surfaces using the flowing of liquid were successfully observed by AFM. And the molecule of DNA can be disconnected by supersonic machine.On the basis of APS, a new modification material was synthesized. By comparing AFM imagines on two kinds of substrates that respectively treated withAPS and newly synthesized modified material, it was found the latter have more clean background. Furthermore, the structures of DNA molecules varying with concentration of new modification agent were studied, and it was found that when the new modification agent concentration (volume ratio) was 1:1000, DNA molecules were successfully fixed and extended on the modified mica surface and well-distinguished DNA strands were imaged by AFM.更多还原