生物纳米材料的自组装及其相互作用的AFM研究

发布时间：2019-07-08 13:51

【摘要】：近年来,通过分子自组装的方式制造新的纳米材料引起了人们的广泛关注和研究。自组装是指分子在没有外界因素引导的条件下自发地由混乱无序的混沌状态组装成有序结构的过程,由于自组装技术生成的纳米材料具有“自发”的特性,在自组装的过程中不需人工干预,因而得到的自组装材料减少了人为因素的干扰,并且具有最佳的组合结构。自组装技术是少数几个可行的纳米结构构造途径之一,研究自组装对制造业、微电子学等学科有很大的的帮助。特别是,自然界中的许多生物分子的纳米结构来源于自组装,如DNA的双螺旋结构、蛋白质的三级四级结构等,都是由小的构筑单元通过自组装形成的。因而研究自组装还有助于人们对生命现象的理解,并且通过模仿这些生命体系中的自组装过程,或者从生命体系中的自组装过程得到启发,来设计新的自组装生物纳米材料,在生物医药领域如抗菌剂、基因和药物载体等领域有很大的潜在应用价值。AFM是一种应用广泛的表面形貌表征工具,它主要是利用探针和样品表面之间的分子间作用力来探测样品表面的起伏,即样品表面的形貌信息。由于AFM对样品的要求相对简单,并且可以在气相、液相环境下对样品进行表征,使得它成为生物纳米材料领域的一种重要表征手段。本文主要是通过AFM研究了几种在生物医药领域,特别是组织工程学、基因及药物载体等领域具有重要应用价值的生物纳米材料的自组装,探索不同条件对它们自组装纳米结构的影响。这些生物材料主要包括三种阳离子多肽,即聚赖氨酸、聚精氨酸、聚组氨酸等,以及三种多糖即壳聚糖、黄原胶、胶凝糖等多糖,除了这些材料的自组装之外,还研究了它们自组装纳米结构之间的相互作用。具体来说,工作主要包括以下几个方面:1、通过培养时间调节三种阳离子多肽,即聚赖氨酸、聚精氨酸、聚组氨酸的自组装纳米材料的结构。这三种阳离子多肽由于其分子链上的正电基团,被应用于抗菌剂、基因和药物载体、生物矿化等领域。在研究中发现,在不同的培养时间内,三种阳离子多肽的自组装纳米结构经历了不稳定聚集体→纳米纤维→纳米颗粒→稳定的纳米薄膜等形貌转变过程。因而通过控制培养时间,可以得到三种多肽的不同的纳米结构。这为更好地利用三种阳离子多肽的自组装纳米材料来做抗菌剂、药物载体提供依据。2、通过控制黄原胶和胶凝糖的浓度、盐度以及母液配制过程中的水浴等条件,得到了黄原胶在云母表面的自组装网状结构和棒状结构,以及胶凝糖的均匀的网状结构。在网状及棒状黄原胶上滴加酸性条件下的壳聚糖或者阳离子多肽,可以使黄原胶纳米结构周围产生很多小纤维,经统计分析发现壳聚糖或三种阳离子多肽在云母表面打开了黄原胶的二级结构,并且带正电的壳聚糖或者阳离子多肽和带负电的黄原胶之间的静电作用是解螺旋的主要驱动力。这一发现对一些淀粉样蛋白引起的疾病如阿兹海默症等的治疗具有潜在的意义。3、研究了黄原胶在义齿树脂表面不同条件下的自组装纳米形貌。这部分内容为黄原胶的纳米结构在牙齿保护中的作用的研究提供铺垫。
[Abstract]:In recent years, the manufacture of new nano-materials by means of self-assembly of molecules has caused extensive attention and research. self-assembly refers to the process of assembling the molecules into an ordered structure spontaneously under the condition that the molecules are not guided by external factors, the nano material generated by the self-assembly technology has the characteristics of "spontaneous", no manual intervention is needed during the self-assembly process, The resulting self-assembled material reduces the interference of human factors and has the best combined structure. The self-assembly technology is one of a few feasible methods to construct the nano-structure, and the self-assembly has great help in the fields of manufacturing and microelectronics. In particular, the nanostructure of many of the biological molecules in the natural world is derived from self-assembly, such as the double-helix structure of the DNA, the three-stage four-stage structure of the protein, and the like, and is formed by self-assembly by a small construction unit. therefore, the self-assembly process of the self-assembled biological nano-material is designed by imitating the self-assembly process in the life system, or from the self-assembly process in the life system, And has great potential application value in the fields of gene and drug carrier and the like. The AFM is a widely used surface morphology characterization tool, which mainly uses the intermolecular force between the probe and the surface of the sample to detect the fluctuation of the surface of the sample, that is, the shape information of the surface of the sample. The requirement of AFM to the sample is relatively simple, and the sample can be characterized in the gas-phase and liquid-phase environment, so that it becomes an important means of characterization in the field of biological nano-materials. In this paper, the self-assembly of several biological materials with important application value in the field of biological medicine, especially the tissue engineering, gene and drug carrier, is studied by AFM, and the effect of different conditions on the self-assembled nano-structure is explored. The biological materials mainly comprise three cationic polypeptides, namely polylysine, polyarginine, polyhistidine, and the like, as well as three polysaccharides, namely chitosan, xanthan gum, gellan gum and the like, besides the self-assembly of the materials, The interaction between their self-assembled nanostructures was also studied. Specifically, the work mainly includes the following aspects:1. The structure of the self-assembled nano-material of polylysine, polyarginine and polyhistidine is adjusted by the culture time. The three cationic polypeptides are used in the fields of antibacterial agent, gene and drug carrier, biological mineralization and the like due to the positive charge group on the molecular chain of the three cationic polypeptides. It was found in the study that the self-assembled nanostructures of the three cationic polypeptides were subjected to the morphology transformation process of unstable aggregates, nano-fiber and nano-particles, and the like in different culture times. Thus, by controlling the culture time, different nanostructures of the three polypeptides can be obtained. this provides the basis for the better utilization of the self-assembled nano-materials of the three cationic polypeptides as the antibacterial agent and the drug carrier, The self-assembled net structure and the rod-like structure of the xanthan gum on the mica surface and the uniform network structure of the gel sugar are obtained. the chitosan or the cationic polypeptide under the acidic condition is dripped on the mesh and the rod-shaped xanthan gum, so that a plurality of small fibers can be generated around the xanthan gum nano structure, and the secondary structure of the xanthan gum is opened on the surface of the mica through the statistical analysis, And the electrostatic interaction between the positively charged chitosan or the cationic polypeptide and the negatively charged xanthan gum is the primary driving force of the dehelix. This finding is of potential significance for the treatment of some amyloid-induced diseases, such as Alzheimer's disease, and studies the self-assembled nano-morphology of xanthan gum under different conditions of the surface of the denture resin. This part provides a foundation for the study of the role of the nano-structure of xanthan gum in the protection of teeth.
【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1

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