L-半胱氨酸修饰的CdTe量子点作为荧光探针的应用研究

发布时间：2018-05-07 07:56

本文选题：量子点 + 半胱氨酸　；参考：《东北大学》2008年硕士论文

【摘要】：量子点以其优越的光学性能,迅速成为人们关注的热点。与传统的有机荧光染料相比,量子点的激发光谱宽而连续、发射光谱窄且对称、发射波长可以通过控制粒径大小和组成来调谐。量子点的荧光强度及稳定性是普通荧光染料的1-2个数量级,并且生物兼容性好,有望成为荧光探针的首选。本论文采用L-半胱氨酸修饰的CdTe量子点作为荧光探针,研究了水溶性量子点与蛋白质的链接,与重金属离子的选择性响应,以及生物应用和化学分析等。具体内容如下：以半胱氨酸修饰的CdTe量子点作为生物探针,建立了一种定量测定人血清白蛋白的新方法。量子点表面的羧基经活化后与蛋白质上的氨基进行共价偶联,可以使量子点的荧光强度得到有效地增强。通过对反应条件的优化,得出在最佳实验条件下,人血清白蛋白在4.0×10-4-8.5 mg/L的浓度范围内与荧光强度呈现良好的线性关系,线性相关系数为0.9994,方法的检出限可达0.13μg/L(3σ),相对标准偏差为0.5%(4.0mg/L,n=11)。将该方法用于人血清中总蛋白含量的测定,结果与考马斯亮蓝G-250测定蛋白质含量的经典方法得到的结果一致。F检验和t检验的结果表明两种分析方法无显著性差异。根据半胱氨酸修饰的CdTe量子点对汞离子的选择性响应,建立了一种量子点作为离子探针定量检测痕量Hg2+的新方法。在最佳实验条件下,量子点荧光强度的变化与Hg2+浓度呈良好的线性关系,线性范围是0.24-15.0μg/L,方法的检出限为0.07μg/L(3σ),对浓度为7.38μg/L的汞标准溶液平行测定11次,得到的相对标准偏差为0.84%。此外,对反应机理进行了探讨,认为汞的加入使CdTe的表面包覆了一层带隙更小的Hg(OH)2,导致体系的荧光淬灭。该方法已成功应用于自来水中汞离子的测定。
[Abstract]:Quantum dots (QDs) have become the focus of attention for their superior optical properties. Compared with traditional organic fluorescent dyes, the excitation spectrum of quantum dots is wide and continuous, the emission spectrum is narrow and symmetrical, and the emission wavelength can be tuned by controlling the particle size and composition. The fluorescence intensity and stability of quantum dots are 1-2 orders of magnitude of ordinary fluorescent dyes, and their biological compatibility is good, which is expected to be the first choice of fluorescent probes. In this paper, CdTe quantum dots modified with L-cysteine were used as fluorescence probes to study the links between water-soluble QDs and proteins, their selective responses to heavy metal ions, biological applications and chemical analysis. The details are as follows: A new method for quantitative determination of human serum albumin (HSA) was established using cysteine modified CdTe quantum dots as biological probe. The fluorescence intensity of quantum dots can be effectively enhanced by covalent coupling of carboxyl groups on the surface of quantum dots with amino groups on protein. By optimizing the reaction conditions, a good linear relationship between the fluorescence intensity and the concentration of human serum albumin in the concentration range of 4.0 脳 10-4-8.5 mg/L was obtained. The linear correlation coefficient was 0.9994, the detection limit of the method was 0.13 渭 g/L(3 蟽 ~ (-1) and the relative standard deviation was 0.50 mg 路L ~ (-1) 路L ~ (11). The method was applied to the determination of total protein content in human serum. The results were in agreement with those obtained by Coomassie brilliant blue G-250 and t-test. There was no significant difference between the two methods. Based on the selective response of cysteine modified CdTe quantum dots to mercury ions, a new method for quantitative determination of trace Hg2 using quantum dots as ion probes has been developed. Under the optimum experimental conditions, the fluorescence intensity of quantum dots has a good linear relationship with the concentration of Hg2. The linear range is 0.24-15.0 渭 g / L, the detection limit of the method is 0.07 渭 g/L(3 蟽 ~ (-1), and the relative standard deviation is 0.84 for the mercury standard solution of 7.38 渭 g 路L ~ (-1) 路L ~ (-1). In addition, the reaction mechanism is discussed. It is considered that the addition of mercury makes the surface of CdTe coated with a layer with smaller band gap, which leads to fluorescence quenching of the system. The method has been successfully applied to the determination of mercury ions in tap water.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R341

【引证文献】