基于环糊精聚合物信号增强机制的可视化分析试纸研究

Visual test paper has drawn increasing attention in the past years, owning to its low cost, portability and on-site test capability. However, many fluorescence-quenching based visual test papers are not applicable due to low specificity, poor selectivity and complex preparation. We have found the excellent fluorescence enhancement during cyclodextrin polymer-fluorophore host-guest interaction. In this proposal, we intend to design and prepare a fluorescence paper printed conveniently by printer, in which cyclodextrin polymer and nucleic acid will be employed as the sensitive signal transformation and high specific target recognition component respectively, and further develop on-site detection for high toxicity biotoxin. First, we will synthesize a series of cyclodextrin polymers with different charge and shapes, and investigate fluorescence change during cyclodextrin polymer-fluorophore interaction for selection and the enhancement mechanism. Secord, aptamer probes and labeled fluorophores will be designed and selected, and we will develop an fluorescence assay method based on cyclodextrin polymer, aptamer and exonuclease, and then research the relationship between fluorescence signal and the concentration of target. At last, we will design and print fluorescence paper precisely by printer, in which cyclodextrin polymer and nucleic acid will be employed, and sensitive on-site detection of ochratoxin A will be projected by combined visual test paper with mobile terminal imaging system. The expected results of this project will provide scientific basis and technical guidance for the development of novel fluorescence enhancement methods and low-cost/portable fluorescence sensors.

荧光淬灭型试纸因存在检测灵敏度低、选择性差和难以制备等问题而抑制了试纸分析技术的进一步发展。本项目拟在前期发现的环糊精聚合物主体结构对染料客体分子的显著荧光增强作用基础上，以优选的核酸适体作为高选择性识别单元，打印制备相应的试纸用于食品安全领域高毒性生物毒素的高灵敏现场检测，以期为发展新型荧光信号增强方法以及低成本、便携式的荧光传感器提供理论基础和技术支撑。具体研究内容如下：(1)制备多种不同电荷属性的环糊精聚合物，筛选主-客体作用过程中荧光信号增强效果良好的环糊精聚合物-荧光染料体系；(2)利用赭曲霉毒素A与其核酸适体之间极强的亲和力，设计核酸适体探针，结合环糊精聚合物的荧光增强能力和核酸外切酶作用，构建荧光增强的传感方法用于赭曲霉毒素A的高灵敏检测；(3)打印制备环糊精聚合物和核酸适体功能化的便携式、低成本荧光分析试纸，结合移动终端实现赭曲霉毒素A的高灵敏现场检测。

发展高灵敏度、高选择性、低成本的现场分析方法用于食品安全的检测已成为当今科学研究的热点和难点。目前常用的荧光淬灭型试纸因存在检测灵敏度低、选择性差和难以制备等问题而抑制了试纸分析技术的进一步发展。本项目制备了多种不同性质的环糊精聚合物，筛选到了主-客体作用过程中荧光信号增强效果良好的中性环糊精聚合物-芘体系；设计核酸适体探针，构建新的高灵敏荧光和电化学分析方法；制备便携式、低成本荧光分析试纸，结合移动终端实现环境中重金属铜离子的可视化现场检测。本项目的成果为发展新型荧光信号增强方法以及低成本、便携式的荧光传感器提供理论基础和技术支撑。 具体的研究内容与成果主要有以下几个方面：.1.制备了多种不同性质的环糊精聚合物，筛选主-客体作用过程中荧光信号增强效果良好的中性环糊精聚合物-芘体系，并结合酶的循环放大能力，实现了血清中小分子三磷酸腺苷的高灵敏检测。.2.以核酸适体作为高特异目标识别单元，以荧光铜纳米颗粒作为高效荧光输出单元，结合外切酶循环放大技术，实现了农产品玉米中高毒性生物毒素赭曲霉毒素的免标记高灵敏检测。.3. 同时，以核酸适体作为高特异目标识别单元，并在茎部插入光敏分子偶氮苯，构建了一种基于紫外-可见光照一步操作实现再生的电化学传感器，并利用该传感器实现了小分子三磷酸腺苷和蛋白凝血酶的高检测。.4. 基于C3N4纳米片的荧光性质和小分子胆固醇对其高效淬灭作用，构建了一种荧光纳米探针用于血清中胆固醇的免标记，高灵敏检测。.5.构建了一种基于CdTe量子点的荧光分析试纸，并结合手机为移动终端，可满足生活饮用水中Cu2+的可视化现场快速检测的要求；为水体中Cu2+的检测提供了一种新的工具，并可望用于水中其它离子或小分子的检测。.6.结合本项目成果和在纳米材料和荧光传感领域所做其它工作，作一综述，总结了此领域的研究现状，并未来发展趋势。