微纳流道中液态生物大分子太赫兹光谱研究

发布时间：2018-02-09 13:51

本文关键词： 蛋白质太赫兹光学参数生理环境牛血清蛋白胃蛋白酶　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：蛋白质是组成人体一切细胞、组织的重要有机大分子,参与几乎所有重要的生命活动。在不同生理环境下蛋白质的定性定量分析是蛋白功能检查、临床诊断、康复检查以及生物药品质量检查的重要指标。目前生化检测方法主要利用蛋白质对应抗体的特异性表达信息获得相应靶分子的种类、含量等信息,过程繁琐,需要花费较多资源。作为一种物理探测方法,太赫兹(THz)技术不需要传统生化检测方法中复杂的标记过程,非常适合对蛋白质直接进行无标记的检测。由于太赫兹波覆盖了生物大分子之间/内的弱相互作用、骨架振动以及偶极子旋转的能级范围,通过生物大分子在太赫兹波段所特有的THz指纹谱可对生物大分子定性分析。另外蛋白含量及构象改变会对THz波段光学参数产生影响,所以光学参数是判定蛋白质种类、含量以及蛋白质变性的主要依据。本文首先概述了太赫兹波以及太赫兹时域光谱技术(THz-TDS)的特性和目前用于生物大分子检测的研究进展。然后介绍了几种经典透射THz-TDS光学参数提取方法。由于超薄微流道的使用法布里-珀罗震荡变得更加显著,对光学参数准确度造成一定的影响。在对前人算法去粗取精的基础上,本文开发了更加简单且更适用于微纳流道的参数提取算法。最后利用开发算法研究了微纳流道中处于不同液态生理环境下蛋白质的太赫兹光谱特性。主要包括两方面:不同浓度牛血清蛋白(BSA)的水化作用研究和不同酸碱环境下胃蛋白酶(Pepsin)构象变化研究。实验结果表明,光学参数(如折射率和吸收系数)与BSA溶液浓度不符合朗博-比尔定律,因为随着BSA溶液浓度的增加BSA蛋白分子含量增高导致其周围的水化层相互重叠。Pepsin溶液的吸收系数在pH=3和pH=5,pH=7以及pH=8.5,pH=11分别处于三种状态,因为Pepsin在pH=2~4的生理环境下才能保证正常的空间构象,在pH=5~7环境中结构发生了一些变化,当pH8.5则发生不可逆的变性。上述研究成果为THz光谱技术定性定量检测蛋白质分子提供了可靠的依据。
[Abstract]:Proteins are important organic molecules that make up all the cells and tissues of the human body, and participate in almost all important life activities. In different physiological environments, the qualitative and quantitative analysis of proteins is the examination of protein function and clinical diagnosis. At present, biochemical methods mainly use the specific expression information of protein corresponding antibody to obtain the information of the target molecule, such as the type and content of the corresponding target molecule, and the process is tedious. It takes a lot of resources. As a physical method of detection, terahertz (THz) technology does not require a complex labeling process in traditional biochemical methods. The THz wave covers the energy levels of the weak / internal interactions between / within biomolecules, the skeleton vibration, and the dipole rotation. Biological macromolecules can be qualitatively analyzed by THz fingerprinting of biological macromolecules in the terahertz band. In addition, protein content and conformation change will affect the optical parameters of THz band, so the optical parameters are to determine the type of proteins. In this paper, the properties of terahertz wave and THz TDSs, and the research progress of THz TDSs used in the detection of biomolecules are reviewed. Then several classical transmissions are introduced. THz-TDS optical parameters extraction method. Because of the use of ultra-thin microchannel Fabry-Perot oscillations become more prominent, The accuracy of optical parameters is affected to some extent. In this paper, a more simple and suitable parameter extraction algorithm is developed. Finally, the terahertz spectral characteristics of proteins in micronanorods under different liquid physiological conditions are studied by using the developed algorithm. Aspects: the hydration of bovine serum protein (BSA) with different concentrations and the conformation changes of pepsin in different acid-base environments. The optical parameters (such as refractive index and absorption coefficient) do not conform to Lambert-Beer 's law with the concentration of BSA solution. With the increase of the concentration of BSA solution, the content of BSA protein molecule increased, and the absorption coefficient of the surrounding hydration layer overlapped. The absorption coefficient of BSA solution was in three states: pH=3, pH ~ (5 +) ~ (5), pH ~ (7) and pH ~ (8.5) ~ (+) ~ (-1) ~ (-1), respectively. Because Pepsin can guarantee normal spatial conformation under the physiological environment of pH=2~4, some changes have taken place in the structure of pH=5~7. When pH8.5 is irreversibly denatured, the above results provide a reliable basis for the qualitative and quantitative detection of protein molecules by THz spectroscopy.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q6-33;O657.3

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