机械球磨法制备碳量子点及其应用

发布时间：2018-01-06 02:04

本文关键词：机械球磨法制备碳量子点及其应用　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：碳量子点是一种颗粒尺寸在1-10 nm之间的新型荧光碳纳米材料,具有独特的光学性质、良好的生物相容性、低细胞毒性、优异的化学稳定性、易于功能化和低成本等特点,在分析检测、生物成像、光催化、电子器件等领域应用广泛。但在实际应用和商业化进程中,其高产制备一直是个难题。机械球磨法是生产纳米材料的常用方法,球磨过程中产生的高能量促使材料发生非平衡态相变和显微组织结构变化,产生新界面和缺陷,使材料粒径更小、比表面积更大,性质更优异,操作过程简便、可批量生产。本文构建了一种新的机械球磨法来制备荧光碳量子点,对其荧光性能、形貌结构进行探索,并尝试将其应用于离子检测和生物成像领域,主要包含以下研究工作:一、首次以纤维素为碳源,镁粉为还原剂,在球磨环境中制得Mg掺杂的荧光碳量子点(Mg-CQDs),并探索了球磨时间和原料比例对Mg-CQDs荧光性能的影响。通过透射电子显微镜(TEM)对其形貌粒径进行表征,该Mg-CQDs粒径分布均匀,平均尺寸在4.7 nm左右,可见明显的晶格条纹。X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、拉曼光谱等表征结果均显示该Mg-CQDs是无定型晶体,含有C、H、O、Mg等元素,且表面富含羟基、羧基等官能团,使得该Mg-CQDs有极好的水溶性。通过紫外可见吸收光谱(UV-vis)、荧光光谱(PL)等表征手段发现,该Mg-CQDs具有很好的吸收和发射性能。此外,还具有优良的抗光漂白性和光稳定性,在强酸强碱、高浓度盐溶液中Mg-CQDs的荧光强度几乎都不改变。并且该Mg-CQDs对Fe~(3+)有较好的响应,可以作为检测Fe~(3+)的纳米探针,检出限为0.9μΜ/L。二、为得到性能更优越的碳量子点(CQDs),我们在本文第一部分研究的基础上,对所得碳量子点进行修饰。即:在球磨的过程中,引入氮源(尿素、对氨基苯甲酸、L-谷氨酰胺等含氮化合物)。所得碳量子点的荧光强度和量子产率均得到提升,其中,以加入L-谷氨酰胺后性能提升最佳。通过透射电子显微镜(TEM)对其形貌粒径进行表征,表明该CQDs粒径分布均匀,平均尺寸在4.8 nm左右,表面富含羟基、羧基等官能团,以及新引入的氨基官能团,有很好的水溶性,同时具备优良的抗光漂白性和光稳定性,在强酸强碱、高浓度盐溶液以及高温环境中,该氮掺杂的碳量子点(Mg,N-CQDs)荧光强度能保持基本稳定。细胞毒性实验表明该Mg,N-CQDs生物相容性良好,同时,以MCF-7细胞为对象,考察了其作为细胞成像试剂的成像效果,结果证明其能进入细胞质中,充分点亮细胞。
[Abstract]:Carbon quantum dots (QDs) are novel fluorescent carbon nanomaterials with particle sizes ranging from 1 nm to 10 nm, with unique optical properties, good biocompatibility, low cytotoxicity and excellent chemical stability. Easy to functionalize and low cost, it is widely used in analytical detection, biological imaging, photocatalysis, electronic devices and other fields, but in the practical application and commercialization process. Mechanical ball milling is a common method to produce nanomaterials. The high energy produced in the process of ball milling makes the materials undergo non-equilibrium phase transition and microstructure changes. New interfaces and defects are produced, which make the materials smaller in particle size, larger in specific surface area, better in properties, simpler in operation and can be produced in bulk. In this paper, a new mechanical ball milling method is proposed to prepare fluorescent carbon quantum dots. The fluorescence properties, morphology and structure were explored and applied in the field of ion detection and biological imaging, including the following research work: firstly, cellulose was used as carbon source and magnesium powder as reducing agent for the first time. Mg doped carbon quantum dots (Mg-CQDs) were prepared in ball milling environment. The effects of milling time and the ratio of raw materials on the fluorescence properties of Mg-CQDs were investigated. The particle size of Mg-CQDs was characterized by transmission electron microscopy (TEM). The size distribution of Mg-CQDs was uniform. The average size is about 4.7 nm, obvious lattice stripes. X ray diffraction and Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) can be seen. The results of Raman spectra showed that the Mg-CQDs was amorphous, containing elements such as CnH, O, mg, and the surface was rich in functional groups such as hydroxyl groups and carboxyl groups. The Mg-CQDs was characterized by UV-Vis and fluorescence spectra. The Mg-CQDs has good absorption and emission properties. In addition, it also has excellent photobleaching resistance and photostability in strong acid and alkali. The fluorescence intensity of Mg-CQDs in high concentration salt solution is almost unchanged, and the Mg-CQDs has a good response to Fe~(3, and can be used as a nano-probe for detecting Fe~(3). The detection limit is 0.9 渭渭 m 路L ~ (-2). In order to obtain better performance carbon quantum dots (CQDsN), we have done some research in the first part of this paper. The carbon quantum dots were modified, that is, nitrogen sources (urea, p-aminobenzoic acid) were introduced into the milling process. The fluorescence intensity and quantum yield of the carbon quantum dots obtained by L- glutamine and other nitrogen-containing compounds have been improved. The particle size of L- glutamine was characterized by transmission electron microscopy (TEM). It was found that the particle size of CQDs was uniform and the average size was about 4.8 nm. The surface is rich in hydroxyl, carboxyl and other functional groups, as well as the newly introduced amino functional groups, which have good water solubility, good photobleaching resistance and photostability, and strong alkali in strong acids. The fluorescence intensity of the nitrogen-doped carbon quantum dot MgN-CQDsremained stable in high concentration salt solution and in high temperature environment. N-CQDs had good biocompatibility. At the same time, the imaging effect of N-CQDs as a cell imaging reagent was investigated. The results showed that N-CQDs could enter the cytoplasm and fully light the cells.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O657.3

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