近红外发光上转换纳米材料的制备及其在生物分析、生物成像中的应用研究

In the project, near-infrared（NIR） luminescence upconversion nanomaterials will be synthesized through some methods including hydrothermal method and solvothermal method by doping different rare-earth ions, regulating the phase transformations of the matrix; gold nanorods with near-infrared absorption properties will be prepared by seed-growth method. In order to apply these nanomaterials as nano-sized biolabeling materials, the surface of these nanomaterials will be modified by transferring from organic solvent to aqueous solution or surface adsorption to keep them water-soluble and biocompatible. With cheap and efficient semiconductor laser(980nm) used as light source, a test and image platform based on the laser confocal technique will be constructed, to develop near-infrared cell imaging and in-vivo analysis. Several efficient fluorescence energy transfer (FET) systems between NIR luminescence upconversion nanomaterials as donor and gold nanorods as acceptor will be built. Based on these FET system, several models including immunoassay, DNA hybridization, aptamer and others similar to sandwich immunoassay will be developed for the detection of antigens, antibodies, DNA sequences, tumor markers, and pernicious microbes(such as E. coli, Staphyloccocus aureus Rosenbach, Salmonella) with high sensitivity and selectivity. The purpose of this plan is to provide new materials, new technology and new methods for immunoassay, early diagnosis, pernicious microbe detection and biomedical imaging in near-infrared region.

本项目拟采用水热法及水热溶剂热法等合成方法，通过掺杂不同的稀土离子以及调控基质材料的相变，来制备近红外发光上转换纳米材料（980nm激光激发，发射波长大于750nm）；利用种子生长法制备具有近红外吸收性质的金纳米棒。通过有机转相或表面吸附等方法对其表面进行功能化修饰，使其适宜用作生物标记材料。利用近红外（980nm）半导体激光器作为激发光源，自组装一套基于激光共聚焦技术的检测、成像装置作为平台，实现近红外区细胞成像及活体分析。以近红外发光纳米材料作为供体，金纳米棒作为受体，构建荧光能量转移（FET）体系，建立基于近红外区检测的免疫分析模型、DNA杂交模型或其他类似夹心反应模型等，实现抗原、抗体、DNA序列、肿瘤标志物、有害微生物（如大肠杆菌、金黄色葡萄菌、沙门菌等）等物质的高灵敏、高选择性检测，以期为疾病的早期诊断、食品中有害微生物检测、生物医学成像等领域提供新材料、新技术、新方法。

课题组采用溶剂热法，通过掺杂不同的稀土离子和控制反应条件等成功地合成了近红外发光稀土掺杂上转换纳米粒子和红区发光稀土掺杂上转换的纳米粒子以及复合结构的稀土掺杂上转换纳米粒子，通过配体交换进行了功能化修饰，并通过透射电镜、吸收光谱、上转换发光光谱、电位分析等手段进行了表征。课题组采用种子生长法成功制备了具有红区和近红外吸收性质的金纳米棒，并通过透射电镜、吸收光谱、电位分析等手段进行了表征。以功能化的稀土掺杂红区和近红外发光上转换纳米粒子为供体，金纳米棒为受体，结合核酸适配体（aptamer）和免疫分析的特异性反应，构建了几种基于核酸适配体和基于人甲胎蛋白（AFP）的免疫分析发光能量转移模型，建立了金属离子、凝血酶、肿瘤标志物（AFP）等物质在红区-近红外区高灵敏、高选择性的测定方法，并应用于血清样品的检测。