【作者】 封宾；

【导师】 王永生；

【作者基本信息】 北京交通大学 ， 光学工程， 2010， 博士

【摘要】 核壳结构纳米复合材料是一种涉及材料学、光学和生物工程学等多门学科的新型材料体系,是通过化学或物理作用,将一种纳米材料包覆于另一种纳米材料表面所形成纳米量级的核壳有序结构。与单一材料相比,核壳问的协同效应使纳米复合材料可集众多特性于一身,在光学器件,生物传感以及荧光探针方面都具有重要的研究价值和广泛的应用前景,吸引了越来越多的科研工作者的关注。本文分别以二氧化硅、聚苯乙烯荧光纳米球、半导体量子点为核,采用不同工艺制备金包覆的核壳结构纳米复合材料,在双重态检测、荧光标记和生物传感等领域的应用进行了比较系统的研究。主要研究内容如下：1、分别以聚苯乙烯荧光微球和CdSe半导体纳米晶为核,引入聚合物组氨酸(PLH)为中间沉积层,直接沉积金离子还原成壳,并在核壳间设计隔离层结构,制备新型的金包覆核壳结构多功能材料。实验结果显示,新材料具有超薄金壳结构,在CdSe@Au样品中金壳最低可达2-3nm左右,隔离层结构能有效克服荧光猝灭现象,最高可抑制荧光衰减达40%以上。通过控制壳层厚度的变化,材料的吸收峰最远可红移至近红外波段约822nm处。2、利用半胱氨酸盐酸盐为稳定剂,采用溶胶-凝胶法在水相中制备出表面具有多种官能团的CdSe纳米晶,对溶菌酶进行了荧光标记的研究。实验结果显示不同粒径的半导体纳米晶材料具备连续变化的吸收和发射光谱,其发射光谱半峰宽窄(<50nm),区分度高,发射峰在475-580nm之间连续可控变化。另外半胱氨酸盐酸盐稳定剂使纳米晶表面同时具有-NH2和-COOH多种官能团,增加生物应用的选择性,操作简单,实现一步标记。3、利用实验制备的金包覆核壳结构纳米复合材料,针对荧光免疫标记,生物素检测,双重态表征等方面进行了深入的研究。实验显示在生物素检测的应用中,CdSe@Au与传统工艺制备的Si02@Au材料相比,灵敏度可提高在6.4倍以上；新材料在前列腺癌LNCaP细胞的荧光免疫检测和双重态表征方面的表现也从应用角度验证了材料的多功能性。更多还原

【Abstract】 Core/shell composite nanomaterial is a new material relating to multiple subjects, such as Materials, Optics and Bio-engineering, etc. Through the chemical and physical effects, core/shell structure is formed by coating shell nanomaterials on the surface of corer nanomaterials. Compared with single materials, core/shell nanomaterials have much more characteristics and its significant research value and broad application prospects in optical devices, biological sensing as well as fluorescent probes are given more and more attention in scientific research. Taking SiO2 microsphere、fluorescence doped polystyrene microsphere and CdSe semiconductor nanocrystal respectively as the core, in this thesis, the synthesis of core/shell composite nanomaterials coated by gold are synthesized using different technology, and a systematic study is done on its application in fluorescent probes, biological sensing, etc. The main contents of the research are as follow:1. Croe/shell composite nanomaterials are produced by taking fluorescence doped polystyrene microsphere and CdSe semiconductor nanocrystal as the core, poly-L-histidihe(PLH) as the Au deposition template, and coating ultra slim gold shell on the surface of the core. As shown in the experimental results, ultra slim gold shell can be produced due to the introduction of PLH, it almost is 2-3nm in CdSe@Au sample. The space structure solves the problem of fluorescent quench. It can enhance more than 40%. In addition, according to the principle of Plasmon resonance, by controlling the thickness of shell, the Au surface Plasmon resonance peak can shift to near infrared band (about 822nm)2. With L-Cysteine(L-Cys) as the stabilizer, CdSe nanocrystal with different diameter and multi-function on the surface is produced using sol-gel method in water, and the study of the fluorescence probe of lysozyme is conducted. Experimental results show that the absorbance and fluorescence spectrum of semiconductor nanocrystals with different grain diameter can shift from 475nm to 580nm continuously, they have narrow Full Wave at Half Maximum(<50nm) and high differentiable, the optical performance is stable. Moreover, the introduction of L-Cys as the stabilizer allows the co-existence of-COOH and-NH2, which provide more choice for the preparation of core/shell materials and their biological application.3. The application of core/shell composite nanomaterials produced in the experiment, in fluorescent probes, biological sensing and the detecting of cellular immunity, are studied by surface functionalization. The Experiments show that the CdSe@Au sample is more sensitive than SiO2@Au made using traditionary method (about 6.4 times). In addition, the application of fluorescence detection for LNCaP cell and dual-modality imaging also prove the multifunctional of our new core/shell composite materials.更多还原