载脂蛋白E的快速分型和灵敏检测的多通道表面等离子体激元共振方法研究

载脂蛋白E（apoE）与阿尔兹海默症（AD）的发生、发展密切相关，是潜在的生物标志物。ApoE的三种表型（apoE2, apoE3和apoE4）只有一个氨基酸残基的差异，但在AD发病进程中的作用完全不同。目前apoE的检测只针对总浓度，尚无法分型，且存在耗时长、步骤繁琐等问题。本项目拟采用多通道表面等离子体激元共振（SPR）技术构建对apoE快速分型和灵敏检测的传感体系，并探讨该方法在实际样品检测中的可行性。将识别apoE三种表型的抗体分别固定于SPR芯片的不同通道上，三种抗体可特异性捕获临床样品中所对应的apoE表型，随后引入适配体-纳米银复合物来放大信号并降低实际样品检测时非特异性吸附的干扰。考察不同apoE表型在临床样本中的分布情况，建立apoE表型及其浓度消长关系与临床结果的关联性。揭示apoE不同表型及浓度对AD患病几率和程度的影响，为AD早期诊断及其发病机理的研究提供科学依据。

Apolipoprotein E (ApoE) contributes to the occurrence and development of Alzheimer disease (AD), serving as a potential biomarker. The three isoforms of apoE (apoE2, apoE3 and apoE4) are identical except for a single amino acid, but behave entirely different in the disease progression. So far, the assay of apoE is only focused on its total concentration, and it still remains a challenge to perform polymorphism analysis. Furthermore, the involved methods are always time-consuming and labor-intensive. In this project, a sensing protocol for phenotyping and quantification of apoE will be developed by a multi-channel surface plasmon resonance (SPR), and the feasibility of the method for assay of clinical samples will be demonstrated. The antibodies that are specific to the three isoforms of apoE are immobilized onto the SPR channels for capturing the corresponding apoE isoforms. Based on the specific interaction of the apoE isoforms toward the aptamer-Ag nanoparticle conjugates, the signal can be amplified and the background effect caused by clinical samples can be reduced. The distribution of the various apoE isoforms will be examined in clinical samples, and the relevance between the phenotyping, concentration fluctuation and the clinical results will be established. The influence of various apoE isoforms and their concentrations on the prevalence of AD provides new insight on the early diagnosis and pathogenesis study of AD.