【作者】 李静；

【导师】 张云怀； 肖鹏；

【作者基本信息】 重庆大学 ， 无机化学， 2008， 硕士

【摘要】 基于碳纳米管（CNTs）的DNA生物传感器兼具碳纳米管良好的导电性和DNA分子自识别性等优异的性能,在生物检测、诊断、电化学检测等方面均表现出较高的效率。本论文通过自组装技术制备多壁碳纳米管（MWNTs）-DNA生物传感器,并对其电化学性能进行检测,初步探讨了该生物传感器对对苯二酚的检测。本文首先对多壁碳纳米管进行混酸处理,用傅立叶红外光谱检测处理前后多壁碳纳米管结构的变化,证明经过混酸处理后的多壁碳纳米管的表面接上了羧基基团,成为羧基修饰的碳纳米管。之后在偶联活化剂1-乙基-（3二甲基氨基丙基）碳酰二亚胺盐酸盐（EDC）和N-羟基硫化琥珀酰亚胺（NHS）作用下,将COOH-MWNTs和NH2-DNA依次通过酰胺键组装在氨基修饰的Pt电极表面,傅立叶红外光谱表明多壁碳纳米管和DNA通过酰胺键连接起来,证明DNA共价修饰在碳纳米管上;利用原子力显微镜和场发射扫描电镜分别对多壁碳纳米管电极和DNA修饰的多壁碳纳米管电极进行表面形貌的检测,结果表明多壁碳纳米管和DNA都成功的组装在Pt电极表面,并且形成的膜排列有序,结构均匀。以铁氰化钾为指示剂,用循环伏安法研究制备的MWNTs-DNA生物传感器的电化学行为。多次循环扫描结果显示电极具有良好的重复性,表明MWNTs-DNA生物传感器具有良好的稳定性;并且随着扫描速度的加快,氧化峰电位正移,还原峰负移,峰电流与扫速的平方根(V^1/2)成正比,说明传感器表面发生扩散控制的准可逆反应。最后,在pH为7.30的生理盐水磷酸盐缓冲溶液中,利用MWNTs-DNA生物传感器,通过循环伏安法和紫外光谱法检测对苯二酚。结果显示:在DNA杂交过程中,对苯二酚与其相互作用后,紫外光谱的吸收峰峰形以及强度改变较大,循环伏安法氧化峰正向移动,峰电流降低,从而推断出,在DNA杂交过程中对苯二酚与DNA以Π-Π化学键和静电结合为主。更多还原

【Abstract】 The DNA biosensor based on carbon nanotubes（CNTs） possess both the excellent electricity of CNTs and the self- identification of DNA, and it exhibits preferable efficiency in the fields of biological detecting, diagnosis, electrochemistry detecting and many others. In the paper, The multi-walled carbon nanotube（MWNTs）-DNA biosensor was built by self-assembly. The electrochemistry of MWNTs-DNA biosensor was detected and the detect to hydroquinone was discussed primarily.First, the MWNTs were functionalized by the mixture of H₂SO₄ and HNO₃, FTIR spectra suggests that carboxylic acid groups were introduced on the surfaces of the nanotubes. Then in the presence of 1-Ethyl-3- （3-dimethylaminopropyl） carbodiimide hydrochloride （EDC） and N-hydroxy- succinimide （NHS）, the carboxylic MWNTs were assembled on amine-modified platinum electrode surface and followed by the assembly of NH₂-DNA with the carboxyl–amine coupling , respectively. Fourier transform infrared（FTIR） demonstrated that NH₂-DNA formed covalent amino bonds with the COOH- MWNTs. Atomic force microscopy （AFM） and Field emission electron microscopy （FEG-SEM） indicating that the MWNTS had been organized on amine-modified Pt electrode surface and DNA are assembled on the MWNTs, forming self-assembled momolayers with orderly orientation and uniform structure.Cyclic voltammetry was used to detect the electrochemistry of MWNTs-DNA biosensor and Fe（CN）₆^4-/ Fe（CN）₆^3- was selected as indicator for their cyclic voltammetric responses. The result indicateing the MWNTs-DNA biosensor has good stability. When the scan rate was increased, the oxidation peak shifted to positive electrode and reduction peak currents shifted to negative electrode, the peak currents are proportional to the square root of the scan rate, indicating a surface-controlled redox process and a diffusion controlled mechanism.Finally, we used the MWNTs-DNA biosensor to detect hydroquinones in PH 7.30 normal saline phosphate buffer solution, cylic voltammetry and ultraviolet-visble spectrophotometry were chosed. The result shows that the peaks and the intension of absorption of ultraviolet-visible spectra in hybridization changed obviously, the oxidated peak of cyclic voltammetry shifted to positive and the peak currents decreased. This fact signified that the electrostatic attraction andΠ-Πbanding between hydroquinones and DNA are the major modes for the interaction in hybridization.更多还原