碳纳米材料放大荧光偏振/各向异性在小分子及金属离子高灵敏检测中的应用研究

Fluorescence polarization/anisotropy has been widely applied in analytical fields because it can provide the informations about the rotational motions of the exited fluorophores. However, most of the conventional methods are limited to the detection of biomacromolecules, and few methods have been reported for the detection of small molecules and metal ions because their molecular masses are too small to produce detectable fluorescence polarization/anisotropy value changes.To address above limitations, a mass amplifying strategy that employs proteins as signal amplifers has been proposed, but suffered the disadvanteges of that protein is unstable and can't be stored for a long time.Present program is to use carbon nanomaterials as fluorescence polarization/anisotropy enhancers, to synthesize various stable and uniform carbon nanomaterials, to investigate the influences of the properties of different carbon nanomaterials, including their shapes, sizes, dispersion states and the distances between fluorophores and carbon nanomaterials, on the enhancement effect,to propose the enhancement mechanism, and finally to apply it to the ultrasensitive detection of drugs, small biomolecules and metal ions, which play important roles in clinical therapies and life activities. This program constructs new fluorescence polarization/anisotropy enhancement strategies, overcomes the disadvantegy of the unstablitiy of the conventional signal amplifers and provides theoretical guidance for the selection of carbon nanomaterials to enhance fluorescence polarization/anisotropy. In addition, it expands the applications of carbon nanomaterials and provides a new idea for the highly sensitive detection of small molecules and metal ions based on the measurements of fluorescence polarization/anisotropy.

荧光偏振/各向异性能够提供荧光体在激发态寿命期间的旋转运动相关信息，已在分析领域得到广泛应用。然而传统方法大多局限于生物大分子检测，很少用于小分子及金属离子检测。尽管可以利用蛋白质放大信号，但蛋白质存在受热不稳定、容易变性以及不便于长期保存等缺点。本项目针对上述问题拟将碳纳米材料用于放大荧光偏振/各向异性信号，首先制备各种稳定均一的碳纳米材料，研究其形状、大小、分散性、荧光基团与碳纳米材料之间的距离等因素对荧光偏振/各向异性增强倍数的影响，提出增强机理，最终用于面向重大疾病的药物及与生命活动密切相关的生物小分子及金属离子的高灵敏检测。本项目在理论上构建了新的荧光偏振/各向异性放大策略，解决了传统信号放大剂不稳定的缺点，为选择碳纳米材料用于放大荧光偏振/各向异性提供了理论指导；在应用上拓展了碳纳米材料的应用范围，为利用荧光偏振/各向异性实现小分子及金属离子高灵敏检测提供了新思路。

传统荧光各向异性法大多局限于生物大分子检测，很少用于小分子及金属离子检测。本项目利用碳纳米材料放大荧光各向异性实现了对金属离子、小分子及生物大分子等多种靶物的灵敏检测。按照预期计划，项目取得了以下主要进展：.1) 利用碳纳米管增强荧光各向异性实现了对DNA的灵敏检测。.2) 利用氧化石墨烯（GO）增强荧光各向异性，通过将染料分子修饰的探针DNA间接连接在GO表面并结合多种信号放大方法，构建了一系列荧光各向异性增强新策略并实现了对钾离子、腺苷、DNA、microRNA、凝血酶及蓖麻毒素的准确、灵敏检测。这些方法一方面解决了引入纳米材料后荧光各向异性信号易受散射干扰从而导致检测信号不准确的缺点，另一方面也克服了传统荧光各向异性检测灵敏度较低的缺点。.3) 考察了不同材料对染料的荧光各向异性的增强能力并研究了染料到GO表面的距离对其增强荧光各向异性的影响，对GO参与的荧光各向异性增强机制进行了初步探讨。