巯基稳定的CdTe量子点与蛋白质相互作用及其细胞毒性的研究
发布时间：2018-08-20 14:53
【摘要】：1.概述了量子点的基本物理特性、有机相和水相合成方法、表面修饰方法,及其在分析科学和生物医学领域的应用及毒理效应的研究现状与进展。在此基础上,提出了本文的研究构想。 2.采用水热合成法,分别以N-乙酰基-L-半胱氨酸(NAC)和巯基丙酸(MPA)为稳定剂,制备出不同粒径的高质量碲化镉(CdTe)量子点。利用紫外可见吸收光谱、荧光光谱、傅立叶变换红外光谱和透射电镜等手段对所制备的NAC/MPA-CdTe QDs进行了表征。结果表明,所制备的量子点粒径分布均一,紫外吸收谱宽而连续,荧光发射峰窄且对称,发射范围几乎覆盖了整个可见区(480-760nm)。通过改变反应时间实现了对量子点荧光发射波长的调制。 3.主要利用荧光光谱法,分别研究了生理条件下CdTe量子点,CdTe/CdS核-壳量子点与细胞色素c(cytochrome c, Cyt c),以及CdTe量子点与牛血清白蛋白(bovine serum albumin, BSA)之间的相互作用。研究发现Cytc对不同粒径的量子点均有显著的荧光猝灭作用；BSA的引入则使量子点的荧光明显增强,而量子点对BSA的荧光表现出明显猝灭效应。探讨了量子点对牛血清白蛋白的荧光猝灭效应、牛血清白蛋白对量子点的荧光增敏效应,以及细胞色素c对量子点荧光猝灭效应的作用机制,为进一步研究量子点与活细胞内蛋白质之间的相互作用提供了实验依据。 4.利用激光共聚焦显微镜分别研究了水溶性MPA-CdTe QD和NAC-CdTe QD与小鼠表皮黑色素细胞B16-F10、人神经胶质瘤细胞SH-SY5Y的相互作用。初步结果显示,相同条件下,MPA-CdTe QD进入细胞的能力强于NAC-CdTe QD; QD进入细胞的能力存在细胞种别依赖性；外源性物种对QD在细胞内的分布存在一定的协同效应。为了进一步提高量子点的生物相容性,利用化学还原的BSA对水溶性CdTeQDs进行了表而修饰。由紫外光谱,荧光光谱和细胞存活率检测实验结果表明,变性BSA被连接到CdTe QDs表面,提高了量子点的化学稳定性和生物相容性。此外,对不同稳定剂(MPA, NAC和dBSA)修饰的量子点与细胞之间的相互作用进行了初步比较研究,结果表明,在相同浓度下MPA-CdTe QDs对细胞存活率影响最大,NAC-CdTe QDs对细胞存活率的影响次之,dBSA-CdTe QDs对细胞存活率的影响最小。实验还表明紫外光照射等外部因素会增强量子点的细胞毒性。上述研究为合成高生物相容性的量子点,最大限度地抑制其细胞毒性以满足生物医学方面应用的要求提供了一定的理论依据。
[Abstract]:1. The basic physical properties of quantum dots, organic and aqueous phase synthesis methods, surface modification methods, their applications in analytical science and biomedicine, and the research status and progress of toxicological effects are reviewed in this paper. On the basis of this, the research conception of this paper is put forward. 2. Using N-acetyl-L-cysteine (NAC) and mercaptopropionic acid (MPA) as stabilizers, high-quality cadmium telluride (CdTe) quantum dots with different particle sizes were prepared by hydrothermal synthesis. The NAC/MPA-CdTe QDs was characterized by UV-Vis absorption spectrum, fluorescence spectrum, Fourier transform infrared spectroscopy and transmission electron microscope. The results show that the size distribution of the QDs is uniform, the UV absorption spectrum is wide and continuous, the fluorescence emission peak is narrow and symmetrical, and the emission range almost covers the whole visible region (480-760nm). The fluorescence emission wavelength of quantum dots was modulated by changing the reaction time. 3. 3. The interaction of CdTe quantum dots with cytochrome c (cytochrome c, Cyt c), and CdTe quantum dots with bovine serum albumin (BSA) under physiological conditions was studied by fluorescence spectroscopy. It is found that Cytc has a significant fluorescence quenching effect on quantum dots with different particle sizes. The introduction of Cytc enhances the fluorescence of quantum dots, while the fluorescence of BSA is obviously quenched by quantum dots. The fluorescence quenching effect of quantum dot on bovine serum albumin, the fluorescence enhancement effect of bovine serum albumin on quantum dot and the mechanism of fluorescence quenching effect of cytochrome c on quantum dot were studied. It provides an experimental basis for the further study of the interaction between quantum dots and proteins in living cells. 4. The interaction of water-soluble MPA-CdTe QD and NAC-CdTe QD with mouse epidermal melanocyte B16-F10 and human glioma cell SH-SY5Y was studied by laser confocal microscopy. The preliminary results showed that the ability of MPA-CdTe QD to enter the cells was stronger than that of NAC-CdTe QD under the same conditions, and the ability of QD to enter the cells was species dependent, and there was a synergistic effect of exogenous species on the distribution of QD in the cells. In order to further improve the biocompatibility of quantum dots, chemically reduced BSA was used to modify water-soluble CdTeQDs. The results of UV spectra, fluorescence spectra and cell survival test show that denatured BSA is connected to the surface of CdTe QDs, which improves the chemical stability and biocompatibility of QDs. In addition, the interaction between QDs modified by different stabilizers, (MPA, NAC and dBSA, was studied. At the same concentration, MPA-CdTe QDs had the greatest effect on cell survival. NAC-CdTe QDs had the second best effect on cell survival, and dBSA-CdTe QDs had the least effect on cell survival. The experiments also show that external factors such as ultraviolet irradiation can enhance the cytotoxicity of quantum dots. These studies provide a theoretical basis for the synthesis of highly biocompatible quantum dots and the maximum inhibition of their cytotoxicity to meet the requirements of biomedical applications.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R114
本文编号：2194040
[Abstract]:1. The basic physical properties of quantum dots, organic and aqueous phase synthesis methods, surface modification methods, their applications in analytical science and biomedicine, and the research status and progress of toxicological effects are reviewed in this paper. On the basis of this, the research conception of this paper is put forward. 2. Using N-acetyl-L-cysteine (NAC) and mercaptopropionic acid (MPA) as stabilizers, high-quality cadmium telluride (CdTe) quantum dots with different particle sizes were prepared by hydrothermal synthesis. The NAC/MPA-CdTe QDs was characterized by UV-Vis absorption spectrum, fluorescence spectrum, Fourier transform infrared spectroscopy and transmission electron microscope. The results show that the size distribution of the QDs is uniform, the UV absorption spectrum is wide and continuous, the fluorescence emission peak is narrow and symmetrical, and the emission range almost covers the whole visible region (480-760nm). The fluorescence emission wavelength of quantum dots was modulated by changing the reaction time. 3. 3. The interaction of CdTe quantum dots with cytochrome c (cytochrome c, Cyt c), and CdTe quantum dots with bovine serum albumin (BSA) under physiological conditions was studied by fluorescence spectroscopy. It is found that Cytc has a significant fluorescence quenching effect on quantum dots with different particle sizes. The introduction of Cytc enhances the fluorescence of quantum dots, while the fluorescence of BSA is obviously quenched by quantum dots. The fluorescence quenching effect of quantum dot on bovine serum albumin, the fluorescence enhancement effect of bovine serum albumin on quantum dot and the mechanism of fluorescence quenching effect of cytochrome c on quantum dot were studied. It provides an experimental basis for the further study of the interaction between quantum dots and proteins in living cells. 4. The interaction of water-soluble MPA-CdTe QD and NAC-CdTe QD with mouse epidermal melanocyte B16-F10 and human glioma cell SH-SY5Y was studied by laser confocal microscopy. The preliminary results showed that the ability of MPA-CdTe QD to enter the cells was stronger than that of NAC-CdTe QD under the same conditions, and the ability of QD to enter the cells was species dependent, and there was a synergistic effect of exogenous species on the distribution of QD in the cells. In order to further improve the biocompatibility of quantum dots, chemically reduced BSA was used to modify water-soluble CdTeQDs. The results of UV spectra, fluorescence spectra and cell survival test show that denatured BSA is connected to the surface of CdTe QDs, which improves the chemical stability and biocompatibility of QDs. In addition, the interaction between QDs modified by different stabilizers, (MPA, NAC and dBSA, was studied. At the same concentration, MPA-CdTe QDs had the greatest effect on cell survival. NAC-CdTe QDs had the second best effect on cell survival, and dBSA-CdTe QDs had the least effect on cell survival. The experiments also show that external factors such as ultraviolet irradiation can enhance the cytotoxicity of quantum dots. These studies provide a theoretical basis for the synthesis of highly biocompatible quantum dots and the maximum inhibition of their cytotoxicity to meet the requirements of biomedical applications.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R114
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