基于量子点的双发射二氧化硅纳米微球的制备及其分析应用研究

发布时间：2018-05-31 11:20

本文选题：离子印迹 + 镉离子　；参考：《浙江工业大学》2016年硕士论文

【摘要】：半导体量子点,又称半导体纳米晶,因其具有优秀的光学性质,在分析检测方面受到越来越多的关注。相比于有机染料,量子点具有亮度高、耐光性强、发射光谱窄、尺寸可调等优点。近年来,量子点作为荧光探针被广泛应用于金属离子、有机小分子、气体、蛋白质和DNA等的检测。相比于单发射波长的荧光量子点,比率荧光探针因其具有更高的灵敏度,能够进行自我矫正以及可视化检测受到了更大的关注。为了提高量子点荧光比率探针在金属离子检测方面的选择性以及在生物样品方面的可视化检测能力,本论文设计合成了两种双发射纳米粒子作为荧光比率探针。主要工作如下:(1)结合“turn-on”模型和“离子印迹”技术,我们设计合成了双发射的量子点杂化纳米粒子,并将它用于水中Cd~(2+)的荧光比率检测。我们通过将绿色荧光的CdSe量子点共价偶联到包埋红光CdTe量子点的硅球表面,合成了比率探针。接着,我们利用EDTA对CdSe量子点表面进行化学刻蚀,CdSe的绿色荧光随之猝灭,同时在CdSe表面产生Cd~(2+)的特异性识别位点。当加入Cd~(2+)后,Cd~(2+)对CdSe表面进行修复,绿色荧光逐渐恢复,而红色荧光保持不变,随着Cd~(2+)离子浓度的增加,我们就可以明显观察到探针溶液发生了从红色到绿色的颜色变化。在最优实验条件下,该比率探针检测Cd~(2+)的检测限达25 nM(S/N=3),线性范围为0.1到9μM。因此,该比率荧光探针提供了一种灵敏度和选择性很高的Cd~(2+)离子检测方法。(2)构建强大的荧光强度比例和颜色可调的双/多发射荧光纳米粒子作为高选择性的荧光比率探针具有重要意义。我们通过将绿色量子点原位生长到包埋红色量子点二氧化硅纳米颗粒的表面,将两种不同尺寸的CdTe量子点在空间上分开,组装合成了一种新型的二氧化硅包覆的双发射杂化纳米粒子CdTe@SiO_2@CdTe@SiO_2。只要简单地控制反应时的回流时间或者改变量子点的前驱体的浓度,我们就可以控制改变该纳米粒子的荧光强度的比值和荧光颜色。相比于之前报道的CdTe@SiO_2@CdTe纳米颗粒,我们合成的CdTe@SiO_2@CdTe@SiO_2纳米粒子表现出更强的光稳定性、化学稳定性以及生物相容性。最后,我们证明了该双发射荧光二氧化硅杂化粒子可以通过荧光能量转移机制,来精确地检测金纳米颗粒浓度。
[Abstract]:Semiconductor quantum dots (QDs), also known as semiconductor nanocrystals, have attracted more and more attention in analysis and detection because of their excellent optical properties. Compared with organic dyes, quantum dots have the advantages of high brightness, strong light resistance, narrow emission spectrum and adjustable size. In recent years, quantum dots (QDs) have been widely used as fluorescent probes for the detection of metal ions, organic small molecules, gases, proteins and DNA. Compared with single emission wavelength fluorescence quantum dots, ratio fluorescence probes have attracted more attention because of their high sensitivity, self-correction and visual detection. In order to improve the selectivity of quantum dot fluorescence ratio probe in metal ion detection and visual detection ability in biological samples, two kinds of double emission nanoparticles were designed and synthesized as fluorescence ratio probes in this paper. The main work is as follows: (1) combined with "turn-on" model and "ion imprinting" technique, we have designed and synthesized double emission quantum dot hybrid nanoparticles, and used it to measure the fluorescence ratio of Cd~(2 in water. A ratio probe was synthesized by covalently coupling green fluorescent CdSe quantum dots to the surface of silicon spheres embedded with red CdTe quantum dots. Then we use EDTA to chemically etch the green fluorescence of CdSe on the surface of CdSe quantum dots and produce the specific recognition sites of Cd~(2 on the surface of CdSe. After the addition of Cd~(2), the surface of CdSe was repaired, and the green fluorescence was gradually restored, but the red fluorescence remained unchanged. With the increase of the concentration of Cd~(2), we observed that the probe solution changed from red to green. Under the optimal experimental conditions, the detection limit of the ratio probe for Cd~(2 is up to 25 nm / s / N ~ (3 +) and the linear range is from 0.1 渭 m to 9 渭 M. Therefore, This ratio fluorescence probe provides a highly sensitive and selective Cd~(2) ion detection method. 2) to construct a strong fluorescence intensity ratio and color adjustable double / multiple emission fluorescent nanoparticles as a high selective fluorescence ratio. The probe is of great significance. By in situ growing green quantum dots onto the surface of silica nanoparticles embedded in red quantum dots, we separate two CdTe quantum dots of different sizes from each other in space. A new type of silica coated double emission hybrid nano-particle CdTeSiO2 was assembled and synthesized. By simply controlling the reflux time during the reaction or changing the concentration of the precursor of the quantum dot, we can control the ratio of fluorescence intensity and the fluorescence color of the nanoparticles. Compared with the previously reported CdTe@SiO_2@CdTe nanoparticles, the synthesized CdTe@SiO_2@CdTe@SiO_2 nanoparticles exhibit stronger photostability, chemical stability and biocompatibility. Finally, we prove that the dual-emission fluorescent silica hybrid particles can accurately detect the concentration of gold nanoparticles by fluorescence energy transfer mechanism.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.3;O613.72

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