PSMA@Ag微球的制备、组装及其增强拉曼散射效应的研究

发布时间：2018-07-12 21:17

本文选题：银 + 原位化学还原　；参考：《大连理工大学》2016年硕士论文

【摘要】：表面增强拉曼散射(SERS)光谱由于具有灵敏度高、抗干扰能力强、无损检测等优点,成为了一种重要的分析手段,被广泛应用在生物、化学和环境检测等方面。合适的基底是实现表面增强拉曼的重要前提。因此,对SERS基底的研究一直是一个重要的研究领域。目前,研究比较多的金银电极和胶体分散液由于增强拉曼“热点”分布无规律,重复性不好。因此,人们制备出贵金属纳米阵列作为拉曼活性基底,能够得到稳定的拉曼信号。但纳米阵列的制备存在制备过程复杂以及成本高的缺点,限制了它们的广泛应用。针对上述问题,本文利用原位化学还原法制备出银包苯乙烯-顺丁烯二酸酐共聚微球(PSMA@Ag)核壳结构纳米微球,并进行自组装得到PSMA@Ag核壳结构蛋白石光子晶体膜,以此作为SERS活性基底,表现出较强的SERS活性。本文通过原位化学还原法制备出了PSMA@Ag核壳结构微球。首先,利用乳液聚合法合成出了单分散PSMA微球,以PSMA微球为核,用聚乙烯亚胺(PEI)对其进行表面修饰；然后加入AgNO3溶液,通过在PSMA微球表面原位还原生成银核；进一步加入乙二胺四乙酸四钠(Na4EDTA)还原,促进银核生长,增加壳层的厚度。分别考察了反应温度、AgNO3溶液浓度以及Na4EDTA溶液浓度等实验条件对产物包覆层的影响,得到了最佳反应条件,制备出了三种不同粒径的分散性好、包覆均匀的核壳纳米微球。制备出的PSMA@Ag微球表面电位值较高。利用垂直沉积法对其进行组装,得到三维有序PSMA@Ag微球蛋白石光子晶体膜。PSMA@Ag光子晶体膜在可见光区具有光子禁带,能够产生结构色。PSMA@Ag光子晶体膜具有强的SERS效应,可以用作SERS基底。研究了基底的Ag纳米颗粒负载量和禁带位置对其SERS效应的影响。随基底Ag纳米颗粒负载量增加,“热点”的数量增加,SERS效应增强。当激发光波长位于禁带边缘处时,由于禁带边缘光子能态密度大,光与分子作用强,起到增强拉曼散射光的作用。本文还研究了PSMA@Ag光子晶体膜对对氨基苯硫酚(PATP)的拉曼增强效果,发现其对对氨基苯硫酚(PATP)的检测限可达到10-8M。测量5个随机点的拉曼光谱,信号峰强度的最大相对偏差为15%。放置30天之后,拉曼光谱特征峰峰强度衰减幅度不大。说明基底灵敏度高、均匀性好、稳定性好。综上所述,本文以简便的操作和低廉的成本制备出了性能优越的SERS基底,在生物、化学和环境分析检测上有重要的潜在应用。
[Abstract]:Surface enhanced Raman scattering (SERS) spectroscopy has been widely used in biological, chemical and environmental detection because of its high sensitivity, strong anti-jamming and nondestructive testing. An appropriate substrate is an important prerequisite for surface enhanced Raman. Therefore, the study of SERS substrate has been an important research field. At present, more gold and silver electrodes and colloidal dispersions have been studied because of irregular distribution of Raman hot spots and poor reproducibility. Therefore, noble metal nanoarrays were prepared as Raman active substrates, and stable Raman signals were obtained. However, the preparation of nanoscale arrays has the disadvantages of complex preparation process and high cost, which limits their wide application. In order to solve the above problems, the Silver-encapsulated styrene-maleic anhydride copolymer nanospheres were prepared by in-situ chemical reduction, and the PSMAAg core-shell opal photonic crystal films were obtained by self-assembly. As a substrate for SERS activity, it shows strong SERS activity. In this paper, PSMA-R Ag core-shell microspheres were prepared by in situ chemical reduction method. Firstly, monodisperse PSMA microspheres were synthesized by emulsion polymerization, and then modified by polyethylene imine (PEI) with PSMA microspheres as core, then silver nuclei were formed by in-situ reduction of silver nuclei on PSMA microspheres by adding AgNO3 solution. Further addition of tetra-sodium ethylenediamine tetraacetate (Na _ 4EDTA) can promote the growth of silver nuclei and increase the thickness of shell. The effects of reaction temperature and concentration of AgNo3 solution and Na4EDTA solution on the coating layer were investigated respectively. The optimum reaction conditions were obtained and three core-shell nanoparticles with good dispersion and uniform coating were prepared. The surface potential of the prepared PSMA-O-Ag microspheres is high. By using vertical deposition method, we found that the photonic crystal film with ordered PSMA-AG opal has photonic band gap in the visible region, which can produce a strong SERS effect on PSMAAg photonic crystal film. Can be used as SERS substrate. The effects of the loading amount of Ag nanoparticles and the position of band gap on the SERS effect of Ag nanoparticles on the substrate were studied. With the increase of Ag nanoparticles loading, the number of "hot spots" increases and the SERS effect increases. When the excited wavelength is located at the edge of the band gap, because of the high energy density of photons at the edge of the band gap and the strong interaction between the light and the molecule, it plays the role of enhancing the Raman scattering light. The Raman enhancement effect of p-aminophenylthiophenol (PATP) on PSMA-@ Ag photonic crystal film is also studied. It is found that the detection limit of p-aminophenol (PATP) can reach 10-8M. The Raman spectra of five random points were measured and the maximum relative deviation of the peak intensity was 15. After 30 days of storage, the intensity attenuation of the characteristic peak of Raman spectrum is not large. It shows that the substrate has high sensitivity, good uniformity and good stability. In conclusion, SERS substrates with superior performance have been prepared with simple operation and low cost, and have important potential applications in biological, chemical and environmental analysis.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.37

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