碳点的制备及其在生物传感的应用研究

发布时间：2019-05-27 20:50

【摘要】：作为新型碳纳米材料,碳点具备各项优异性能,被广泛地应用于各个研究领域。碳点的粒径一般在3~5 nm之间,表面含有各类功能化基团,且可通过改变功能化基团来改变碳点的溶解性。相对于传统的半导体量子点来说,碳点具有更好的光学性能、生物相容性和环境友好性,可以应用于生物成像、纳米传感、光催化、光电子器件等领域。本文基于文献报道的碳点制备方法,利用微波辅助法制备出性能优良的荧光碳点;结合碳点和金簇的合成方法成功地制备出了复合纳米碳点材料,并应用于细胞内离子检测、双色细胞成像、有机染料的光催化降解等方面:(1)本实验以葡萄糖为前驱物,用微波辅助法制备出大尺寸荧光碳点,碳点表面复杂的功能化基团使其可以和各种金属离子相互作用。基于钾离子对碳点荧光的猝灭作用,实验构建了高效、特异性检测钾离子含量的生物传感器,检测限为1.0×10-1 2 M。实验成功检测了人血清中钾离子的含量,检测结果和医院提供的参考值基本一致。相比于其它传感器复杂的表面功能化修饰、繁琐的仪器操作,本实验构建的生物传方法,无需进行任何表面修饰,消耗低,操作简单、快捷,具有非常大的应用潜力。(2)本实验以微波辅助法制备了具有独特性质的复合碳纳米材料-含金碳点(GCDs)。并对其进行了高分辨透射电镜(HRTEM)、XRD、高角环形暗视场扫描透射电子显微镜(HAADF-STEM)、EDS等表征,表征结果表明含金碳点是由碳和金复合组成的。微小的金纳米簇分散在2 nm左右的碳点骨架上,含金碳点同时具有碳点和金簇的部分性质,如类过氧化物酶性质及单激发/双发射性质等。含金碳点双发射峰对目标物不同的响应使得其可以应用于纳米传感及细胞成像中。基于含金碳点的耐光性、生物相容性及良好的荧光性能,实验在乳腺癌细胞及老鼠成骨细胞中对其进行了双荧光细胞成像。最后,利用其比率型荧光细胞成像定性地检测了老鼠成骨细胞中三价铁的含量。(3)本实验基于含金碳点模拟酶性质建立了超灵敏、可视化检测前列腺癌抗原的传感方法。通过对氯金酸、双氧水以及稳定剂的条件优化,建立灵敏的显色反应;实现了可视化及定量检测前列腺癌抗原的目的,检测限达到了10-1 9 g/m L,并进一步检测了前列腺癌患者血清中前列腺癌抗原的含量。此方法与传统的酶联免疫吸附方法相比,操作简单、灵敏度高,具有更低的检测限。(4)本实验将末端含有巯基的DNA单链适配体通过金硫键修饰到含金碳点的表面。利用和DNA适配体的特异性结合作用进一步将前列腺抗原(PSA)修饰到含金碳点的表面。前列腺抗原属大分子,因此将前列腺抗原修饰到含金碳点表面时,含金碳点的共振光散射强度会发生明显的变化。前列腺癌抗原浓度在0.01 ng/m L~0.05 ng/m L范围内时,碳点的共振光散射强度变化值和前列腺癌抗原浓度成线性关系。以修饰了DNA适配体的含金碳点为探针,实验定量检测了前列腺抗原的量且检测了生物样品中前列腺癌抗原的含量,为临床疾病诊断提供一种可能的方法。(5)本实验基于碳点的光催化活性和金纳米颗粒的等离子体性质,成功实现了在各种光(紫外、可见、近红外光)照射下,催化降解罗丹明B。碳点具有较弱的光催化活性,金纳米颗粒的等离子体性质,可以大大提高碳点的光催化活性,基于此实现了罗丹明B在各种光照下的光催化降解,且成功实现了紫外/可见光的协同催化,大大提高了实验的光催化效率。
[Abstract]:As a new carbon nano-material, carbon dots have excellent properties and are widely used in various fields of research. The particle size of the carbon dot is generally between 3 and 5 nm, the surface contains various functional groups, and the solubility of the carbon point can be changed by changing the functional group. Compared with the traditional semiconductor quantum dots, the carbon dots have better optical performance, biocompatibility and environmental friendliness, and can be applied to the fields of biological imaging, nano-sensing, photocatalysis, optoelectronic devices and the like. The method for preparing the carbon point based on the literature report has the advantages that the fluorescent carbon point with excellent performance is prepared by the microwave-assisted method, the composite nano-carbon-point material is successfully prepared by combining the synthesis method of the carbon point and the gold cluster, and the composite nano-carbon-point material is applied to the intracellular ion detection and the two-color cell imaging, The photocatalytic degradation of organic dyes and other aspects are as follows: (1) The experiment uses glucose as a precursor, and a large-size fluorescent carbon point is prepared by a microwave-assisted method, and a complex functional group on the surface of the carbon dot can be used for interacting with various metal ions. Based on the quenching effect of potassium ion on the fluorescence of carbon spot, a biosensor with high efficiency and specific detection of potassium ion content was constructed. The detection limit was 1.0-10-1 2M. The content of potassium ion in human serum was successfully detected, and the results of the test and the reference value provided by the hospital were basically the same. Compared with the complex surface functionalization modification and complex instrument operation of other sensors, the biological transmission method constructed by the experiment does not need to carry out any surface modification, has low consumption, simple and rapid operation, and has very large application potential. (2) The composite carbon nano-material-gold-bearing carbon-point (GCDs) with unique properties was prepared by microwave-assisted method. The high-resolution transmission electron microscopy (HRTEM), XRD, high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), EDS and the like were characterized. The results showed that the gold-bearing carbon point was composed of carbon and gold. The small gold nanoclusters are dispersed on the carbon point skeleton of about 2 nm, and the gold-bearing carbon point has the partial properties of carbon and gold clusters, such as the properties of the peroxidase and the properties of single excitation/ double emission. The two emission peaks of the gold-bearing carbon point have different responses to the target, so that it can be used in the nano-sensing and cell imaging. Based on the light resistance, biocompatibility and good fluorescence properties of the gold-bearing carbon spot, the double-fluorescent cell imaging was performed in the breast cancer cells and mouse osteoblasts. And finally, the content of the trivalent iron in the rat osteoblast is qualitatively detected by using the ratio-type fluorescent cell imaging. (3) The method for sensing prostate cancer antigen was established based on the properties of the gold-bearing carbon-point analog enzyme. By optimizing the conditions of the chloroauric acid, the hydrogen peroxide and the stabilizer, a sensitive color development reaction is established, the purpose of visualization and quantitative detection of the prostate cancer antigen is realized, the detection limit reaches 10-1 9 g/ m L, and the content of the prostate cancer antigen in the serum of the prostate cancer patient is further detected. Compared with the traditional enzyme-linked immunosorbent assay, the method has the advantages of simple operation, high sensitivity and lower detection limit. And (4) the experiment is to modify the DNA single-chain aptamer containing the polar base through the gold-sulfur bond to the surface of the gold-containing carbon point. The prostate antigen (PSA) is further modified to the surface of the gold-containing carbon point by the specific binding action of the DNA aptamer. The prostate antigen is a macromolecule, so the resonance light scattering intensity of the gold-bearing carbon point can change obviously when the prostate antigen is modified to the surface of the gold-containing carbon point. When the antigen concentration of the prostate cancer is within the range of 0.01 ng/ m L to 0.05 ng/ m L, the resonance light scattering intensity change value of the carbon point and the concentration of the prostate cancer antigen are linear. The gold-bearing carbon point of the DNA aptamer is modified as a probe, and the amount of the prostate antigen is quantitatively detected by the experiment, and the content of the prostate cancer antigen in the biological sample is detected, and a possible method is provided for clinical diagnosis. (5) The catalytic degradation of rhodamine B under the irradiation of various kinds of light (ultraviolet, visible and near-infrared light) under the irradiation of various kinds of light (ultraviolet, visible and near-infrared light) was successfully achieved on the basis of the photocatalytic activity of the carbon spot and the plasma properties of the gold nanoparticles. The photocatalytic degradation of the rhodamine B under various illumination can be greatly improved, and the synergistic catalysis of the ultraviolet/ visible light is successfully realized, and the photocatalytic efficiency of the experiment is greatly improved.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.3

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