新型高性能氮掺杂碳点的设计、制备与应用研究

发布时间：2018-02-23 18:42

  本文关键词： 氮掺杂碳点 水热法 蜂蜜 聚丙烯酰胺 水性聚氨酯 5-氧代-3 5-二氢-2H-噻唑[3 2-a]吡啶-7-羧酸 荧光检测Au(Ⅲ) 谷胱甘肽 生物成像 荧光复合薄膜　出处：《南京大学》2015年博士论文　论文类型：学位论文

【摘要】：碳量子点,简称碳点,是一类小尺寸并且具有荧光特性的新型碳基纳米材料。由于其低生物毒性及环境友好性、良好的荧光性能、优异的分散性和化学稳定性、优异的抗光漂白性、易修饰性和低成本等特点在生物成像与生命标记、分析检测、催化和光电子器件等领域有着广泛的应用前景。虽然关于碳点合成和应用的报道络绎不绝,但目前碳点仍存在着诸如荧光效率偏低、主要荧光发射波长多在蓝光、缺乏调控手段和应用研究不深入等亟待解决的问题。本论文针对这些问题以蜂蜜和氨水、聚丙烯酰胺、水性聚氨酯等为碳源,利用水热法设计制备了一系列新型高性能的氮掺杂碳点,通过改变反应条件或碳源组成来调节所制备碳点的性质(包括尺寸、溶解性和发光波长等),并将碳点应用于生命分析、生物成像和荧光薄膜等领域,主要包含以下四个方面的工作：(1)以天然蜂蜜为原料,在外加氨水的条件下,采用水热法一步制备出粒径在5nm左右,在365nm紫外灯照射下发射蓝光的氮掺杂碳点,并发现氮元素的掺杂能够提高碳点的荧光效率。该碳点可以构建荧光淬灭/恢复("off-on")探针用以检测Au(Ⅲ)和谷胱甘肽。研究发现Au(Ⅲ)对制得的碳点具有选择性淬灭并形成Au(Ⅲ)修饰的碳点团簇,而Au(Ⅲ)修饰的碳点团簇的荧光可以被谷胱甘肽等巯基生物分子特异性恢复。这一新型方法可用于检测不同氧环境下细胞内谷胱甘肽的含量。(2)进一步以本体含氮的聚丙烯酰胺为碳源,采用水热法一步制得了荧光效率大于10%的氮掺杂碳点,通过控制水热反应的时间(24、72和96小时)可以获得不同粒径(5、20和50nm)的荧光碳纳米粒子。通过透射电镜、动态光散射、红外、紫外、荧光光谱等手段对得到的荧光碳纳米粒子的形貌、结构和荧光性质进行了表征。获得的碳纳米粒子可以应用于快速细胞成像,1小时即可观察到荧光信号。另外,研究发现荧光碳纳米粒子的尺寸与其进入细胞的能力相关,20 nm的粒子胞吞效果最好。(3)以水性聚氨酯乳液为原料,通过水热法一步制得可分别在水相和有机相溶解的碳点,两种碳点表面所含的官能团不同导致其溶解性的差异。水相碳点具有良好的荧光性能(荧光效率大于20%)和低生物毒性并可以应用于多色细胞成像；有机相碳点可均匀分散于多种有机溶剂,由此可进一步应用于荧光薄膜材料的制备。研究还发现,通过选择不同的水性聚氨酯软段,可以调控水相和有机相碳点的产率；同时通过选择不同种类的二异氰酸酯可以将获得碳点的发光由蓝光调控至蓝绿光。(4)为了进一步提高材料的荧光效率,以柠檬酸和巯基乙胺为原料进行水热反应,结果得到了荧光效率大于90%的小分子5-氧代-3,5-二氢-2H-噻唑[3,2-a]吡啶-7-羧酸(TPCA)。通过质谱、核磁、荧光光谱等手段表征了其结构并研究了其荧光性质。
[Abstract]:Carbon quantum dots, or carbon dots, are a new type of carbon based nanomaterials with small size and fluorescence properties. Due to their low biotoxicity and environmental friendliness, good fluorescence properties, excellent dispersion and chemical stability, Excellent photobleaching resistance, easy modification and low cost are widely used in the fields of biological imaging and life marking, analytical detection, catalysis and optoelectronic devices. However, there are still some problems in carbon spots, such as low fluorescence efficiency, the main emission wavelengths of fluorescence are blue light, lack of regulation and application research, etc. In this paper, honey and ammonia, polyacrylamide, and so on, are needed to solve these problems. A series of high performance nitrogen-doped carbon spots were prepared by hydrothermal method. The properties of the prepared carbon points (including size) were adjusted by changing the reaction conditions or the composition of carbon sources. Solubility and luminescence wavelength, and the application of carbon spots in the fields of life analysis, biological imaging and fluorescent film, mainly includes the following four aspects of work: 1) using natural honey as raw material, under the condition of added ammonia water, The nitrogen-doped carbon spots with the diameter of about 5 nm and the emission of blue light under the irradiation of 365nm ultraviolet lamp were prepared by one step hydrothermal method. It was also found that nitrogen doping can improve the fluorescence efficiency of carbon points, which can be used to construct fluorescence quenching / recovery ("off-on") probes for the detection of Au( 鈪，

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