利用银纳米簇研究糖与凝集素的相互作用及汞离子的检测研究

发布时间：2018-03-03 00:19

本文选题：银纳米簇　切入点：D-甘露糖　出处：《青岛科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：目前,具备荧光性质的纳米材料发展十分迅速,尤其是以DNA为模板合成的银纳米簇(Ag NCs),其最大的特点是可以通过变换不同的DNA序列和长度能够实现从可见光到近红外的荧光可调控发射。此外,它还具有制备方法简单、光稳定性好、低毒性、生物相容性良好的优点,因此受到很多研究学者的青睐。本论文对DNA稳定的银纳米簇展开研究和应用,包括利用糖修饰银纳米簇检测伴刀豆蛋白A、肿瘤细胞成像检测、利用银纳米簇与T-Hg~(2+)-T的复合结构对汞离子进行灵敏检测,主要开展以下研究。一是,基于DNA稳定的银纳米簇和D-甘露糖与伴刀豆蛋白A(Con A)的特异性结合作用,我们实现Con A的荧光检测。设计方案是:N-DNA富含胞嘧啶,作为银纳米簇的成核序列,此时制备的银纳米簇荧光微弱,G-DNA链富含鸟嘌呤,当富含鸟嘌呤的G-DNA序列靠近银纳米簇时,其荧光强度会明显增强。D-甘露糖修饰在两条DNA链的不同末端。当有Con A存在时,就会诱导两条DNA链靠近,从而使荧光增强,达到检测Con A的目的。Con A在1.0×10-12到1.0×10-7M之间时,其浓度与体系的荧光强度成良好的线性关系。二是,基于DNA稳定的银纳米簇和D-甘露糖与MDA-MB-231细胞表面特异性受体识别的作用,通过成像手段检测肿瘤细胞。实验首先用巯基乙酸糖化制备羧基-α-D-甘露糖,通过羧基与氨基的共价作用,使得甘露糖修饰在DNA序列的末端,该DNA带有银纳米簇的成核序列。当DNA与硝酸银和硼氢化钠作用之后就会形成银纳米簇。当与细胞一起培育时,该荧光探针就会与细胞表面受体特异性结合,从而实现癌细胞识别成像研究。三是,由于DNA与Hg~(2+)有特殊的相互作用,能够形成T-Hg~(2+)-T的复合结构,我们开发出一种免标记检测汞离子的简便方法。实验中我们设计一个汞离子存在时能通过T-Hg~(2+)-T结构形成茎环结构的DNA序列。加入Exo III对茎环结构进行剪切,释放出目标物Hg~(2+)和银纳米簇的模板链,释放出的目标物Hg~(2+)能够再次进入到循环中,形成新的茎环结构。利用这种方法,我们实现了Hg~(2+)的定量检测,Hg~(2+)的浓度在3.0×10-11到3.0×10-8 M时,浓度与荧光强度呈良好的线性关系。
[Abstract]:At present, with the development of the fluorescence properties of nano materials is very rapid, especially with DNA as the template for the synthesis of silver nanoclusters (Ag NCs), its biggest feature is through the DNA sequence and length transform can realize different from visible to near infrared fluorescence emission can be controlled. In addition, it also has the preparation the method is simple, good light stability, low toxicity, good biocompatibility and good, so by many scholars of all ages. This thesis research and application of silver nanoclusters DNA stable, including the detection of the use of sugar modified silver nanoclusters with egg white concanavalin A, tumor cell imaging detection, the use of silver nanoclusters and T-Hg~ (2+) -T composite structure for sensitive detection of mercury ions, mainly in the following research. First, the DNA stability of silver nanoclusters and D- mannose with concanavalin A (Con A) based on the specific binding, we implement Con A fluorescence detection Test. The design scheme is: N-DNA is rich in cytosine, as nuclear sequence into silver nanoclusters, fluorescent silver nanoclusters prepared at the weak, G-DNA chain guanine rich guanine rich sequences of G-DNA, when close to the silver nanoclusters, the fluorescence intensity will be significantly enhanced.D- mannose modified in different end of two strands of DNA. When Con A, will be induced by two DNA strands near, so that the fluorescence enhancement, to detect Con A to.Con A in the 1 * 10-12 to 1 * 10-7M, the fluorescence intensity of the concentration and the system of a good linear relationship. The two is that the DNA stability of silver nanoclusters and D- mannose with the specific MDA-MB-231 cell surface receptor recognition based on the effect of tumor cell detection by imaging means. The first experiment with mercaptoacetic acid saccharification and preparation of carboxylated alpha -D- mannose, through covalent interactions of carboxyl and amino groups, the mannose modification in DNA sequence In the end, the DNA sequence of nucleation with silver nanoclusters. After DNA with silver nitrate and sodium borohydride will form silver nanoclusters. When cultivated together with cells, combined with the fluorescent probe will with a cell surface receptor specificity, so as to realize the imaging of cancer cell recognition. The three is due to DNA and Hg~ (2+) has special interaction, can form T-Hg~ (2+) -T composite structure, we developed a simple method for label free detection of mercury ions. In our experiment design through the T-Hg~ there is a mercury ion (2+) -T formation sequence of DNA stem loop structure. Adding Exo III cut the stem loop structure, release the object Hg~ (2+) and silver nanoclusters template chain, the release of the target Hg~ (2+) to enter into circulation again, form a stem loop structure. Using this new method, we implement the Hg~ (2+) quantitative detection, Hg~ (2+ concentrated) When the degree is 3 * 10-11 to 3 x 10-8 M, the concentration has a good linear relationship with the fluorescence intensity.

【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3

【参考文献】