石墨烯基复合纳米材料的制备及其在生物传感器方面的应用研究

发布时间：2018-03-30 02:24

本文选题：石墨烯/银纳米复合材料　切入点：丝网印刷电极　出处：《北京印刷学院》2015年硕士论文

【摘要】：电化学免疫传感器，作为分析生物技术的一个重要领域，能够针对性地实现对目标物质快速的分析和追踪。但传统的电化学免疫传感器结构复杂，需要引入标记物用以增强传感响应，不仅耗时耗力、价格高昂，且易因生物分子变性而出现误差，无标记型电化学免疫传感器则无需标记，操作简单、分析时间快速、测量精确；同时，玻碳电极作为目前常用的基础电极，在使用时需要反复打磨，操作繁琐也造成了检测误差，而丝网印刷电极不仅保证了低成本、批量化生产，还实现了电极的微型化、便携性；此外，传统电极材料的导电性能较低，需要进行修饰，用以提高其电化学响应性能。本课题针对上述存在的问题，从电极材料的制备入手，以柠檬酸钠为银纳米颗粒的保护剂，水合肼、柠檬酸钠为双还原剂，在温和条件下“一锅”法制备得到石墨烯/银纳米复合材料。通过调整投料比，实现对负载银纳米颗粒粒径(16.6 35.8nm)和分布量(0.16 59.63%)的可控调节，结果显示该复合材料具有较高的导电性(rGO固含量为40%时电导率值为35.48S/cm)和电化学响应性(100mV/s扫面速率下峰电流可达45uA)。采用石墨烯/银纳米复合材料修饰丝网印刷三电极体系的工作电极，在提高电极表面电子传输能力、放大检测信号的同时，银纳米粒子也为前列腺癌特异性抗体提供了吸附位点，制作了一种无标记型电化学免疫传感器。结果显示，该传感器具有快速响应性，对前列腺癌特异性抗原的最低检测限可达0.01ng/mL，线性检测范围为1 1000ng/mL，具有良好的特异性、重复性和稳定性。此外，本论文还制备了一种具有磁响应性和生物可降解特性的新型基因载体，通过溶剂热法制备超小粒径油相四氧化三铁纳米颗粒，，其粒径约为4-8nm，饱和磁化强度可达27.27emu/g；再者，采用内消旋-2,3-二巯基丁二酸二次交换该纳米颗粒表面的油酸分子，获得水相分散性好的磁性纳米颗粒，其饱和磁化强度增至35.67emu/g；最后，由酰胺化反应将支链型聚乙烯亚胺接枝到水相四氧化三铁纳米颗粒表面，得到具有基因递送能力的磁响应性基因载体，其表面zeta电位可高达52.5±1.94mV，仍具有一定的超顺磁性(14.48emu/g)。此外，细胞水平结果显示，该基因载体对EGFP质粒具有一定的递送效率。
[Abstract]:Electrochemical immunosensor, as an important field of bioanalysis technology, can be used to analyze and track the target material quickly, but the structure of traditional electrochemical immunosensor is complex. It is necessary to introduce markers to enhance the sensing response, which is not only time-consuming and expensive, but also prone to errors due to biomolecular denaturation, while the unlabeled electrochemical immunosensors need no labeling, so they are easy to operate and analysis time is fast. At the same time, the glassy carbon electrode, as the basic electrode commonly used at present, needs to be polished repeatedly in use, and the complicated operation also causes the detection error, and the screen printing electrode not only guarantees the low cost, but also the mass production. The electrode is miniaturized and portable. In addition, the traditional electrode material has low conductivity and needs to be modified to improve its electrochemical response performance. In order to solve the above problems, starting with the preparation of electrode materials, sodium citrate was used as the protective agent of silver nanoparticles, hydrazine hydrate and sodium citrate were used as double reductants. The graphene / silver nanocomposites were prepared by "one pot" method under mild conditions. By adjusting the feeding ratio, the particle size of loaded silver nanoparticles was 16.6 ~ 35.8 nm) and the distribution of silver nanoparticles was 0.16 ~ 59.63). The results show that the conductivity of the composite is 35.48s / cm when the solid content of rGO is 40) and the peak current of the composite is up to 45uAn at the sweep rate of 100mV / s. The working electrode of the three-electrode system was modified by graphene / silver nanocomposites, which can improve the electronic transmission ability on the electrode surface and amplify the detection signal. Silver nanoparticles also provided an adsorption site for prostate cancer specific antibodies, and an unlabeled electrochemical immunosensor was developed. The results showed that the sensor had rapid response. The minimum detection limit for prostate cancer specific antigen was 0.01ng / mL, and the linear detection range was 1 / 1000ng / mL, which had good specificity, reproducibility and stability. In addition, a novel gene carrier with magnetic response and biodegradability was prepared. The ultrasmall oil phase iron trioxide nanoparticles were prepared by solvothermal method. The particle size was about 4-8 nm, and the saturation magnetization reached 27.27 emu / g. The oleic acid molecules on the surface of the nanoparticles were exchanged twice by using racemic -2o 3-dimercaptosuccinic acid to obtain magnetic nanoparticles with good water dispersion. The saturation magnetization of the nanoparticles increased to 35.67 emu / g, and the saturation magnetization of the nanoparticles was increased to 35.67 emu / g. The branched polyethyleneimine was grafted onto the surface of Fe _ 2O _ 3 nanoparticles in aqueous phase by amidation reaction, and the magnetic responsive gene vector with gene delivery ability was obtained. The surface zeta potential of the vector was as high as 52.5 卤1.94 MV, and it still had a certain superparamagnetic potential of 14.48 emu / g. Cell level results showed that the gene vector had a certain delivery efficiency to EGFP plasmid.
【学位授予单位】：北京印刷学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP212;TB333

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