血浆中β淀粉样多肽的存在形态及其在线检测方法的研究

Alzheimer’s disease (AD) is the most common cause of dementia in the elderly population. Due to swelling aging population, the people suffering from Alzheimer’s disease are expected to increase. So, there is a clear need for the development of widely available, inexpensive and reliable methods to diagnosis AD in the earliest stages, which will facilitate tracking disease progression and effective therapeutics for patients. The advantage of blood-based biomarkers is obvious－obtaining blood is easier than almost any other body fluid, and blood-based tests lend themselves to high-throughput and cheap measurements. Amyloid-β (Aβ) is the most widely studied plasma biomarker for AD. Because of the binding between Aβ and other proteins in plasma, the conventional methods for plasma Aβ detection led to conflicting results. This research is aimed to develop a reliable technique for the accurate detection and analysis of Aβ in plasma. First, we are going to study the interaction between Aβ and other proteins commonly existing in plasma by using capillary electrophoresis (CE), and get the Aβ separated from other proteins in plasma by CE technique. The separated Aβ can be enriched on the functionalized TiO2 nanowire-based assay which is coupled to the mass spectrum (MS) for the rapid mass and structural analysis of Aβ. After decorating the Ru-containg dye on the Aβ enriched TiO2 nanowire assay, the contents of Aβ can be determincated by using photoelectrochemistry (PEC) method. In summary, a detection system will be established for the accurate online detection of plasma Aβ by couplying CE to functionalized TiO2 nanowire assay and applying PEC methods, which will benefit to the diagnosis of AD in the earliest stages.

阿尔茨海默病（AD）是全球发病率最高的老年神经退行性疾病。随着老龄化程度的加剧，AD患病群体人数日益剧增。因此亟待开发一种能实现AD低成本、且能广泛执行的早期诊断技术，为AD的治疗和病情的监测提供帮助。血液标志物具有取样操作简单，适用于低成本、高通量检测的优点。β-淀粉样肽( Aβ)是研究最广泛的AD血浆标志物。本课题针对血浆中Aβ与蛋白结合导致目前检测结果存在争议的问题，拟用毛细管电泳技术（CE）研究Aβ与血浆中常见蛋白的相互作用，并在此基础上利用CE实现对血浆中Aβ与蛋白的分离；利用功能化的TiO2纳米线材料对CE分离的Aβ进行富集，并联用质谱对Aβ进行分析；在富集有Aβ的TiO2纳米材料基底上，修饰上含钌化合物染料利用光电化学（PEC）方法实现对Aβ的定量检测，由此开发出一套CE、功能化纳米基底捕获材料、PEC联用方法实现对血浆中Aβ的在线检测，为AD患者的早期诊断提供有效技术手段。

重要小分子及离子的有效检测是相关疾病（如老年痴呆症）与环境监测的关键手段。有机功能分子具有广泛的多样性，且通过分子结构的选择和调控便可得-到优化的各种性能。本项目研究思路为利用及设计多功能的有机分子来构建有效的检测方法体系，包括光电化学方法、荧光法、比色法等，来对老年痴呆症标志物Aβ与相关重要小分子、离子，以及多种重要环境毒性分子和离子进行检测。基于该研究思路与研究内容，主要开展了如下几个方面的研究。.提出了基于多功能光敏分子的光电化学传感器的构建策略，即光敏分子能同时实现光电转换及目标物的识别等功能。基于此提出的设计策略，我们利用N3染料实现了对Hg2+的高灵敏检测；以血红素为光敏剂实现了对Aβ寡聚体的高灵敏检测。该策略的提出与实验研究将为新型光电化学传感器的开发提供了有效思路。另外基于Aβ寡聚体与血红素复合物的催化性能，还利用比色法实现了对Aβ寡聚体的有效检测。.对部花青染料的水解机制及其影响因素进行了深入的探究。为基于部花青染料探针的设计及有效抑制其水解副反应提供了可靠的方法。基于天然多肽的良好生物相容性与水溶性优点，我们以天然三肽（GGH）为识别基团，构建了一种用于双重检测Cu2+与S2-的水溶性荧光探针。利用该探针体系实现了对S2-高特异性与高灵敏检测，检测限为0.44 μM，并对细胞内Cu2+与S2-进行了成像检测。基于萘酰亚胺与三氰呋喃大π体系骨架开发了两种用于检测肼的荧光探针，其检测限分别为0.27 和0.13 μM，并进一步对肼荧光探针的种类与机理进行了综述，深入讨论了探针的响应机理，为新型肼荧光探针的开发提供了思路。基于苯并噻唑荧光骨架开发了两种高效检测活性氧次氯酸根的荧光探针，并发现了一种新的次氯酸根的检测机理，为更多有效次氯酸根探针的发展提供了新的策略。