基于荧光金纳米簇及新型发光金复合物的生物传感应用研究

发布时间：2017-12-28 08:02

本文关键词：基于荧光金纳米簇及新型发光金复合物的生物传感应用研究　出处：《北京科技大学》2015年博士论文　论文类型：学位论文

【摘要】：金纳米簇是一类由几个到几百个金原子组成的新型的发光纳米材料,其独特的结构和性质引起了人们极大的研究兴趣。金纳米簇尺寸介于单原子和金纳米颗粒之间,直径一般小于3 nm。尽管金纳米簇和金纳米颗粒之间并没有十分确切的界限,但是我们还是能从它们光学性质的差别将它们区分开来。金纳米簇的尺度接近电子的费米波长,因此连续的能态性质分裂为离散的能态,并出现类似分子的尺寸依赖效应,导致了其和金纳米颗粒截然不同的光学行为的性质。荧光金纳米簇除了表现出来很多的分子相似的光学性质外,大的比表面积,易表面修饰,和发射波长可调等也是其重要特点。和其他类型的发光材料相比,金纳米簇有许多自己的优势,比如合成相对简单,良好的水溶性,低毒,生物兼容等特点。因此,荧光金纳米簇具有广阔的应用前景。同时,我们也意识到荧光金簇和传统荧光剂一样会因聚集而引起其荧光强度的降低,限制其在成像中进一步应用。因而,我们需要立足于对金簇发光原理的认识,去继续探索更加优异的新型金发光材料。具体内容及结论如下：首先,我们用一种简单的方法开发了一种可重复使用的,荧光Cu2+传感器。它是通过将聚电解质和AuNCs@BSA形成的复合物固定到玻璃基底表面来制备的。接下来的荧光研究表明,薄膜传感器的荧光能有效的被Cu2+淬灭,同时又能被EDTA恢复,这个循环过程能重复至少15次。这表明我们制备的Cu2+传感器是可重复利用的。我们同时考察了它对实际自来水体系中的分析性能,Cu2+检测的回收率能达到96.3-99.6%。其次,我们通过去除金簇的办法首次揭示了AuNCs@蛋白质体系中diY的存在。我们的实验结果证实,在形成的金簇的过程,蛋白结构也相应的发生改变,比如,众所周知的破坏蛋白中的二硫键以及我们所揭示的形成diY交联。diY在410 nm处有很强的发射峰,而在AuNCs@BSA体系中diY荧光很弱。因此,我们探究了diY荧光淬灭机理,发现在AuNCs@BSA体系中由于FRET和IFE的作用从而导致diY荧光淬灭。同样的,在其他的体系中,如AuNCs@LYZ和AuNCs@OVA同样也存在类似的效应。接下来,半胱胺刻蚀引起的AuNCs@BSA荧光淬灭被首次用来开发出一种基于刻蚀方法的免标记免分离的半胱胺选择性传感器。我们发现半胱胺有很强的刻蚀能力,能刻蚀BSA保护的金簇核,从而引起其荧光淬灭。同时,其他的血清中存在的巯基类小分子,比如谷胱甘肽和半胱氨酸,以及其他不含巯基的19种天然氨基酸的存在,不会干扰半胱胺刻蚀金簇反应以及半胱胺的检测。在优化的pH条件下(pH 8.5),构建传感器的线性范围为500-10,000nM,最低检测限位150 nM(信噪比为3)。我们这种分析方法在去蛋白的血清样品中同样得到了满意的结果。最后我们成功制备了一种新型的金发光复合物。我们首次采用从上到下策略合成,利用金簇作为合成源来制备新材料。我们进行了一系列的表征和研究。这种方法得到的产物具有AIE性质。加入Cd2+后上清液质谱表征为[Au4(SR)3]+。同时这种产物具有良好的分散性,预期在传感,生物成像有很好前景。
[Abstract]:Au nanoclusters are a new type of luminescent nanomaterials composed of several hundred to hundreds of gold atoms. Their unique structure and properties have attracted great interest. The size of gold nanoclusters is between monatomic and gold nanoparticles, and the diameter is generally less than 3 nm. Although there is no exact boundary between gold nanoscale and gold nanoparticles, we can distinguish them from the differences in their optical properties. The size of gold nanoclusters is close to the Fermi wavelength of electrons, so the continuous state of energy can be divided into discrete energy states, and the size dependent effect of molecules appears, leading to the distinct optical behavior of gold nanoparticles. In addition to many similar molecular optical properties, fluorescent gold nanoclusters are also important for their large specific surface area, surface modification and tunable emission wavelength. Compared with other types of luminescent materials, gold nanoclusters have many advantages, such as relatively simple synthesis, good water solubility, low toxicity, and biocompatibility. Therefore, the fluorescent gold nanoclusters have a broad application prospect. At the same time, we also realize that the fluorescent gold cluster and the traditional fluorescein will cause the decrease of the fluorescence intensity due to the aggregation, which limits its further application in the imaging. Therefore, we need to be based on the understanding of the principle of gold cluster luminescence, to continue to explore a more excellent new type of blonde light material. The specific contents and conclusions are as follows: first, we developed a reusable, reusable, fluorescent Cu2+ sensor with a simple method. It is prepared by fixing the complex of polyelectrolyte and AuNCs@BSA to the surface of the glass substrate. The subsequent fluorescence studies show that the fluorescence of the thin film sensor can be effectively quenched by Cu2+ and can be recovered by EDTA, and this cycle can be repeated at least 15 times. This indicates that the Cu2+ sensor we have prepared is reusable. At the same time, we investigated its performance in the actual tap water system, and the recovery rate of Cu2+ detection can reach 96.3-99.6%. Secondly, we first revealed the presence of diY in the AuNCs@ protein system by removing the gold clusters. Our experimental results confirm that the protein structure is also changing during the formation of gold clusters, for example, the two sulfur bonds in the damaged protein, as well as the formation of diY crosslinking. DiY has a strong emission peak at 410 nm, and the diY fluorescence is very weak in the AuNCs@BSA system. Therefore, we explored the fluorescence quenching mechanism of diY and found that the fluorescence quenching of diY was caused by the effect of FRET and IFE in the AuNCs@BSA system. Similarly, in other systems, such as AuNCs@LYZ and AuNCs@OVA also have similar effects. Next, cysteamine etching induced AuNCs@BSA quenching is the first time to develop a label free separation cysteamine selective sensor based on etching method. We found that cysteamine has a strong etching ability, which can etch the gold cluster nucleus of BSA protection and cause its fluorescence quenching. Meanwhile, the existence of sulfhydryl small molecules in other sera, such as glutathione and cysteine, and other 19 natural amino acids without sulfhydryl group, will not interfere with cysteamine etching gold cluster reaction and cysteamine detection. Under the optimized pH condition (pH 8.5), the linear range of the sensor is 500-10000nM, the minimum detection limit is 150 nM (the signal to noise ratio is 3). Our analytical method also obtained satisfactory results in the serum samples of protein deproteinized. In the end, we have successfully prepared a new type of blonde complex. For the first time, we use the upper and lower strategy synthesis and the gold cluster as a synthetic source to prepare the new material. We have carried out a series of characterization and research. The product obtained by this method has the properties of AIE. After adding Cd2+, the mass spectrum of the supernatant was characterized by [Au4 (SR) 3]+. At the same time, the product has good dispersibility, and it is expected to have a good prospect in sensing and biological imaging.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O657.3;TP212.3

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