【作者】 刘仁勇；

【导师】 张忠平；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2009， 硕士

【摘要】 分子印记技术(Molecular Imprinting Technology,MIT)是一种制备对特定分子具有专一识别性能的聚合物的技术,基于分子印记技术制备的分子印记聚合物材料具有高亲和性和选择性、抗恶劣环境能力强、稳定性好、制备成本低、使用寿命长,应用范围广等优点而在分离提纯、免疫测定、生物模拟、仿生传感、催化、环境的痕量分析、药物释放等以及相关领域显示出广阔的应用前景。本文首先对分子印记技术的基本原理、分子印记聚合物的制备、分子印记技术应用状况以及分子印记技术新发展进行了较为全面的综述和评价,探讨了当前分子印记技术所面临的机遇和挑战。传统方法制得的印记聚合物有效印记点的密度很低,因此对目标分子的结合容量小,结合动力学慢,难以满足在传感器上应用的实际需要。纳米结构的分子印记材料具有较高的比表面积,印记材料上大多结合位点位于或接近材料表面,对目标分子具有高亲和力,快速结合动力学等特点,有望真正解决传统分子印记遇到的困难,进一步推动分子印记技术的发展。通过对粒子表面进行修饰制备分子印记聚合物材料是一个较好的方法。本论文重点针对农药分子的识别与检测,以二氧化硅为中心粒子,利用层层自组装技术,发展制备具有高选择性、高亲和力和快速结合动力学的芯-壳型纳米结构印记材料。同时,结合荧光分析技术,发展基于金属卟啉荧光淬灭的表面分子印记聚合物的制备。二氧化硅粒子表面layer-by-layer分子印记。首先,在氮气气氛中和惰性溶剂里APTS通过共价耦联到二氧化硅纳米粒子的表面,用戊二醛进行交联,得到表面改性的二氧化硅纳米粒子。然后,利用聚烯丙基胺(PAA)与2,4-D之间的相互作用制备前驱组装体复合物(PAA-2,4-D),以此复合物为构筑基元与戊二醛交替组装在改性的二氧化硅纳米粒子表面上。通过组装的循环次数,可在纳米级别上控制壳层的厚度。结果表明所得的芯-壳型分子印记聚合物对2,4-D具有强的识别能力,对所有的2,4-D结构类似物的吸附能力均低于对2,4-D的吸附能力。本研究拓展了分子印记聚合物的制备,有可能成为纳米传感器中用于分子识别的理想材料。基于锌原卟啉(ZnPP)的表面分子印记聚合物的制备和荧光检测。首先,用γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷(MPS)对二氧化硅纳米粒子进行表面改性,制得表面键合有双键的改性二氧化硅纳米粒子,然后诱导功能单体甲基丙烯酸(MAA)和ZnPP在二氧化硅粒子表面印记聚合。锌原卟啉直接作为功能单体参与形成空腔,其即为识别元件又为探测元件。实验结果证实了这种发光性分子印记聚合物可以实现对痕量农药残留分子的高灵敏度和高选择性的检测,为农药的残留检测提供了新的途径。更多还原

【Abstract】 Molecular imprinting technique (MIT) is becoming increasingly recognized as a powerful technique of preparing synthetic polymers that contain tail-made recognition sides for certain molecules. The most significant advantages of molecularly imprinted materials are high affinity and high selectivity to analyte, mechanical/chemical stability, low cost and ease of preparation, usage of long lifetime, and hence have attracted extensive research interests due to the potential application in purification, separation, immunoassay, biomimics, chemical and biological sensors, catalysis, environment detection, drug release and other relevant fields for its predetermination, specificity and practicability of molecule recognition.The research described in this thesis gives a brief overview of the development of novel strategies facilitating advanced understanding of the fundamental principles governing selective recognition of molecularly imprinted polymers, and discusses the problems and challenges that molecular imprinting technique meets with at present. Traditional molecular imprinting techniques often produce the polymer materials exhibiting low binding capacity and slow binding kinetics due to low density of effective recognition sites, limiting their use in sensors. As an alternative to these approaches, nano-sized imprinting materials may provide a potential solution to these difficulties due to their extremely high surface-to-volume ratio which lead to the recognition sites to locate at the surface and in the proximity of materials surface, so they have a high affinity and fast binding kinetics. It’s a wise strategy to prepare molecular imprinting materials at the surface of support cores through a simple modification. This thesis aims at pesticides recognition and detection. Taking advantage of the LBL technique, silica core-shell imprinted nanomaterials with high selectivity, high affinity and rapid binding kinetics had been prepared. Moreover, combining with fluorescence analysis technique, a surface molecularly imprinted polymer was prepared based on fluorescence quenching of metalloporphyrin.Layer-by-layer molecular imprinting at the surface of silica particles. Firstly, Aminopropyl modification of silica nanoparticles was carried out through the covalently attached to silica surface using 3-aminopropyltriethoxylsilane at inert solvent under nitrogen atmosphere. Followed by cross-linked with glutaraldehyde (GA), then the modified silica was obtained. The imprinting complex (PAA-2,4-D) was prepared by the intermolecular interaction between 2,4-D and PAA. Then, PAA-2,4-D and GA were sequentially assembled onto the surface of modified silica. The shell thickness can be tuned at the nanometer scale by controlling the number of layers. The results showed that imprinted materials had high recognition ability to 2,4-D, and the binding capacity of all of 2,4-D related compounds are lower than that of 2,4-D. The research reported here extends the preparation of MIPs, and can be used as ideal materials for molecular recognition in the field of nanosensors.Preparation of surface molecularly imprinted polymers and fluorescence detection based on zinc (II) protoporphyrin (ZnPP). Firstly, surface-modified silica particles which contain double bonds were obtained by modified with 3-(trimethoxysilyl) propylmethacrylate (MPS), and it can direct the selective occurrence of imprinting polymerization at the surface of silica. Using ZnPP as functional monomer to form cavities directly,it can be served not only as recognition element but also as signal-generating element. It has been demonstrated that this molecularly imprinted polymer which may emit fluorescence can be used to detect pesticide residue sensitively and selectively. These results reported herein may provide a new design for the detection of pesticide residues.更多还原