【作者】 胡泊；

【导师】 黄承志；

【作者基本信息】 西南大学 ， 分析化学， 2008， 硕士

【摘要】 碳纳米管自从1991年被发现以来,由于其具有独特的结构、电子、机械及化学特性在复合材料、修饰电极、传感器和生物等方面得到了广泛的应用。本文利用多壁碳纳米管具有很强的光散射信号和对氧化还原反应有催化作用,提出了以碳纳米管为基础的DNA和有机小分子药物分析方法,并利用多壁碳纳米管的催化作用合成金纳米花。内容包括以下三个方面:(1)将DNA探针分别修饰在磁小珠(MPs)和多壁碳纳米管(MWNTs)表面上,修饰后的多壁碳纳米管能够分散在水溶液中,当用紫外可见光激发时具有很强的光散射信号。如果此时靶物DNA存在,通过形成三明治结构可以将探针修饰的多壁碳纳米管和磁小珠连接起来,在一外磁场作用下就可以很容易将MP-MWNTs从溶液中分离出来,导致上清液光散射强度降低。因此,通过检测以DNA修饰的MWNTs作为识别单元的光散射信号,实现了DNA杂交分析和PCR产物分析。实验表明此传感器至少能重复使用17次,稳定6个月。(2)在pH 2.36的酸性条件下,多壁碳纳米管能催化氯金酸氧化还原性药物盐酸四环素生成金纳米微粒。金纳米微粒具有强烈的表面等离子共振吸收和光散射,且光散射信号变化比吸收信号变化灵敏。通过检测反应生成的金纳米微粒的等离子体共振光散射信号,本文建立了一种快速、简便的检测盐酸四环素含量的方法。生成的金纳米微粒的等离子共振光散射信号与盐酸四环素的浓度呈良好的线性关系,线性范围为4～26μmol/L,相关系数(r)为0.9955,检出限(3σ)为6.0 nmol/L。将该方法用于盐酸四环素片剂分析,平均加标回收率为101.9%;用于尿液分析,加标回收率为98.3-102.0%。(3)多壁碳纳米管可以催化氯金酸氧化多巴胺。通过调节多巴胺的浓度可以得到大粒径的金纳米微粒或者金纳米花。虽然生成的金纳米颗粒和金纳米花有相同的散射光谱,但是它们的特征吸收峰位置不同。多巴胺浓度较低时生成粒径不均匀的金纳米微粒,吸收峰在560nm;多巴胺浓度较高时便会生成金纳米花,吸收峰在470nm。更多还原

【Abstract】 Owing to the unique structure, electronics, machanical and chemical properties, carbon nanotubes （CNTs） have been wildly used in the fields of composite materials, modification of electrodes, sensors and biology since their discovery in 1991. This article puts forward new analytical methods for DNA hybridization and organic small molecules based on the multi-wall carbon nanotubes （MWNTs） which have very strong light scattering signals and have the catalysis to the redox reaction. The main content is as follows:（1） A visual sensor for DNA hybridization with DNA probe-modified MPs and MWNTs respectively. DNA probe-modified MWNTs could be dispersed in aqueous medium and have strong light scattering signals under the excitation of a light beam in the UV-Vis region. DNA probe-modified MWNTs could connect with DNA probe-modified MPs together in the presence of perfectly complementary target DNA and form a sandwich structure. In a magnetic field, the formed MP-MWNT species can easily be removed from the solution, resulting in a decrease of light scattering signals. Thus, by measuring the light scattering signals with DNA-modified MWNTs as recognition elements, this sensor could be used in DNA hybridization and PCR products analysis. And this sensor could be reused at least 17 times and was stable for more than 6 months.（2） It was found that MWNTs could catalyze the redox reaction between hydrochlorauric acid （HAuCl₄） and reductive drugs such as tetracycline hydrochloride （TC）, producing gold nanoparticles （Au NPs）. Au NPs have the intense plasmon absorption and light scattering signals, and the light scattering signals are more sensitive than the absorption signals. By measuring the plasmon resonance light scattering （PRLS） signals of the resulted Au NPs, tetracycline hydrochloride can be detected simply and rapidly with a linear range of 4²6μmol/L, a correlated coefficient （r） of 0.9955, and a limit of detection （3a） of 6.0 nmol/L. This method has been successfully applied to the detection of tetracycline hydrochloride tablets in clinic with the recovery of 101.9% and that of fresh urine samples with the recovery of 98.3—102.0%.（3） MWNTs could catalyze the redox reaction between hydrochlorauric acid and dopamine. By controlling the concentration of dopamine, we can synthesize gold nanoparticles or gold nanoflowers of large size. The gold nanoflowers have the same light scattering spectrum as gold nanoparticles, but their characteristic absorbtion peak is different. Gold nanoparticles could be synthesized when dopamine concentration is lower with a new absorption peak nearby 560 nm, on the other hand, gold nanoflowers could be synthexized when dopamine concentration increased to 5.0×10^-4 mol/L, and a new absorption peak could be presented nearby 470 nm.更多还原