化学腐蚀法可控制备SiC量子点成型机制及其性能研究

发布时间：2018-04-05 07:37

本文选题：碳化硅量子点　切入点：化学腐蚀法　出处：《山东农业大学》2017年硕士论文

【摘要】：活体细胞长时程荧光成像示踪及其细胞精细结构显示为生命科学研究提供了重要的技术支撑,可以用于细胞生长规律、转基因寻踪及动物疾病防治等领域,但传统的荧光材料(如荧光蛋白、荧光染料、CdX量子点等)均不适合于活体细胞的长时程荧光成像与示踪。近年来新型碳化硅量子点(SiC-QDs)由于具有优良的生物相容性及光学性能,可以作为一种活体细胞长时程荧光成像示踪材料,被材料界与生物学界学者所瞩目。但到目前为止,化学腐蚀法可控制备SiC-QDs工艺与性能优化、成型机制、活体细胞标记机制等问题还没有得到系统研究。本文针对这些问题进行了一系列研究,结论如下:(1)以自蔓延燃烧合成的均质纳米SiC颗粒为原料,通过化学多重腐蚀,机械研磨结合超声破碎,超重力场层析剪裁等工艺参数优化,系统研究了SiC量子点成型过程中微观形貌的演变规律及制备工艺参数对SiC量子点光学特性的影响规律,揭示了量子点制备工艺-微观结构-光学特性间的相互关联机制,形成了一种SiC量子点标记材料可控制备工艺,其步骤为:纳米均质SiC自蔓延燃烧合成→配制混合腐蚀液→进行SiC颗粒腐蚀→降酸→烘干→机械研磨→SiC颗粒二次腐蚀→降酸→烘干→机械研磨→超声空化破碎→高速离心层析剪裁→SiC量子点收集。(2)研究了新型工艺可控制备SiC量子点的荧光特性及其致病镰刀菌活体细胞标记强度与机制。结果表明:当激发光为340 nm时,SiC量子点光致发光强度最大,随激发光波长增加,发射波长发生红移,具有较高的斯托克斯位移。由于荧光发射可以全色调谐,可实现近紫外或近红外荧光检测,实现了自发荧光细胞的有效检测与定量分析。对致病镰刀菌活体细胞SiC量子点荧光标记机制的研究结果表明,量子点通过网格蛋白依赖的内吞方式进入活体细胞内部,并均匀分布,从而实现了稳定荧光标记。另外基于实验结果与理论分析,提出了致病镰刀菌活体细胞SiC量子点荧光标记模型。(3)研究了量子点荧光标记对致病镰刀菌自身生理生长的影响,得出标记后菌株在生长速度、产孢与产色素能力均未表现出抑制现象,与对照组几乎同步生长,证明了碳化硅量子点具有优良的生物相容性与荧光强度稳定性;最后借助量子点的荧光标记动态示踪技术,对尖孢镰刀菌致病机制进行了研究,并提出了致病性尖孢镰刀菌引起的植物枯萎病致病机理。
[Abstract]:In vivo, long term fluorescence imaging and fine cell structure display provide important technical support for life science research, and can be used in cell growth law, transgenic tracing, animal disease prevention and treatment, and so on.However, traditional fluorescent materials (such as fluorescent proteins, fluorescent dye CdX quantum dots, etc.) are not suitable for long term fluorescence imaging and tracer of living cells.In recent years, new silicon carbide quantum dots (SiC-QDss) have been widely used as a long time fluorescence imaging tracer material for their excellent biocompatibility and optical properties.However, so far, the process and performance optimization, molding mechanism, in vivo cell labeling mechanism of controlled preparation of SiC-QDs by chemical corrosion method have not been systematically studied.In this paper, a series of studies have been carried out to solve these problems. The conclusions are as follows: (1) using homogenous SiC particles synthesized by self-propagating combustion as raw materials, mechanical grinding combined with ultrasonic crushing is carried out by chemical multi-corrosion.Optimization of processing parameters such as super gravity field chromatography trimming and so on. The evolution law of microstructure and the influence of preparation parameters on the optical properties of SiC quantum dots were studied systematically in the process of forming SiC quantum dots.The correlation mechanism between the preparation process, microstructure and optical properties of quantum dots was revealed, and a controllable preparation process of SiC quantum dots was formed.The steps are as follows: Nano-homogenous SiC self-propagating combustion synthesizer is used to prepare mixed corrosion solution for SiC particle corrosion reduction and acid-reducing drying and mechanical grinding of SiC particles secondary corrosion / drying machine grinding and ultrasonic cavitation crushingThe fluorescence characteristics of SiC quantum dots prepared by a new technique and the labeling intensity and mechanism of SiC quantum dots in vivo were studied.The results show that when the excitation light is 340 nm, the photoluminescence intensity of sic QDs is the highest. With the increase of excitation wavelength, the emission wavelength is red-shifted and has a high Stokes shift.Because the fluorescence emission can be tuned in full color, the near ultraviolet or near infrared fluorescence detection can be realized, and the effective detection and quantitative analysis of autofluorescence cells can be realized.The fluorescence labeling mechanism of SiC quantum dots in vivistic cells of Fusarium sp. was studied. The results showed that quantum dots entered the living cells through the endocytosis mode dependent on grid proteins and distributed evenly, thus realizing stable fluorescence labeling.In addition, based on the experimental results and theoretical analysis, a fluorescence labeling model of SiC quantum dots in vivistic cells of Fusarium disease was proposed. The effects of quantum dot fluorescence labeling on the physiological growth of pathogenic Fusarium were studied, and the growth rate of the labeled strain was obtained.The ability of spore production and pigment production showed no inhibition, and almost synchronized growth with the control group, which proved that silicon carbide quantum dots had excellent biocompatibility and fluorescence stability.The pathogenetic mechanism of Fusarium oxysporum was studied and the pathogenetic mechanism of Fusarium oxysporum was put forward.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.72;TB383.1

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