基于多功能量子点生物传感器的基础与实用初步研究-应用化学专业论文.docxVIP

摘要本文研究了一种新型的分子灯塔探针，即以磁性荧光量子点N比dTe作为能 摘要 本文研究了一种新型的分子灯塔探针，即以磁性荧光量子点N比dTe作为能 量给体，BHQ2作为能量受体，通过弓形虫特征序列的单链DNA合成发卡式灯 塔探针，并对其实用性能进行了初步研究。 在水相中合成了稳定的具有窄而对称荧光发射带的量子点CdTe，以巯基丙 酸作为表面修饰剂，对其进行了红外表征，得到了荧光量子产率为27．3％，浓度 为1．29X 1旷M，粒径为2．6nm的CdTe半导体纳米粒子。 研究了水合肼还原法制备磁性纳米粒子Ni的反应机理，并以此为基础，选 用不同的修饰剂对磁性纳米粒子表面进行修饰，获得了分散性及稳定性良好的磁 性纳米粒子，更易于外层包裹。利用层层自主装方法，将CdTe量子点包裹到磁 性纳米粒子表面，得到N粥dTe磁性荧光复合纳米粒子。 选取磁性．荧光复合纳米粒子Ni／CdTe与3’端连有淬灭剂BHQ．2的单链弓形 虫DNA合成灯塔探针，考察了该灯塔探针的稳定性、特异性和灵敏度(即探针 的最低浓度检测限)，并用于完全匹配目标DNA以及单碱基变异的目标DNA的 检测。 通过层层自组装的方法将各元件组装到金电极上，以裸金电极为基底电极， 依次组装量子点CdTe层和探针ssDNA层，构成DNA电化学传感器，对其性能 进行了考察与研究。 关键词：Ni／CdTe，磁性荧光复合纳米粒子，荧光共振能量转移，弓形虫DNA， 灯塔探针，电化学传感器 AbstractA Abstract A novel molecular beacon(MB)sensing probe with the hairpin structure was synthesized by linking magnetic-fluorescence composite nanopa舭s Ni／CdTe，used as energy donor,and commercial dyes BHQ2 as energy accepter through a single-stranded Toxoplasma gondii DNA,and its practical performance Was preliminarily studied． With high quantum dots yields of 27．3％，the qualified CdTe quantum dots showing narrow and symmetric emission spectrum were successfully prepared in aqueous phase,and its average size and concentration Were calculated to be 2．6rim and 1．29x 1 0。6 M respectively． The synthesis mechanism of magnetic nanoparticles nickel，prepared bY chemical reduction with hydrazine hydrate in ethylene glycol has been suggested．On this basis， different modifiers were used to improve the surface condition of magnetic nanoparticals，resulting to the good dispersion and stability of magnetic nanoparticles and with being more easily outer coated．Then the shell material Cdl’e was fabricated to the surface of magnetic cores，by layer-by-layer method． According to the principle of fluorescence resonance energy transfer(FRET)，the typical single-stranded Toxoplasma gondii DNA Was successfully labeled with the multifunctional QDs attached to the 5’end of DNA and the commercial dyes BHQ2 attached to the 3’end of DNA．The sensitivity,specificity and stability o