甲基化定量分析是精确评估DNA甲基化偏倚的关键技术。目前的基因组Bisulfite-Seq分析存在测序深度、转换效率和庞大数据分析等不足；MSRE分析引物设计受RE识别序列限制更不能精确定量5mC位点数量。本项目在对甲基化DNA结构分析和项目组前期研究证实，甲基化DNA液相条件下形成以CH3-为内核的疏水球这一物化特性基础上，利用pcPNA捕获不同位点甲基化的靶序列DNA后，靶序列CH3-疏水球在电极表面膜微环境分布的密度与对膜表面反应介质的空间位阻差异，建立DNA 5mC位点数量与电化学响应数学模型，达到精确定量DNA甲基化水平的目的。并在深入解析pcPNA电化学传感液相响应机理基础上，利用pcPNA双螺旋侵袭特性，进一步探索dsDNA甲基化定量分析的可行性和基础参数。通过研究，拟为表观遗传和临床甲基化定量检测建立一种原创性的新的技术手段，同时阐明甲基化电化学分析碱基最适间距等基础理论。

Quantitative analysis of methylation is the key technique for accurate assessment of DNA methylation bias. Currently, the bisulfite-sequencing technology has been used for the detection of genome methylation, but it has some shortcomings such as the requirements of a deep-sequencing, incomplete conversion and big data analysis. The MSRE analysis was limited by the RE recognition sequence, therefore, the number of 5mC sites could not be precisely quantified with this technique. Our previous research showed that the molecular characterization of methylated DNA would change into hydrophobic grouping CH3- in liquidoid, and form a CH3-core hydrophobic sphere. .Therefore, in this study, we intend to establish an electrochemical analytic technique for exact quantitative DNA methylation level based on the liquidoid characteristic of CH3-hydrophobic sphere structure, the electroneutral backbone pcPNA would be used to capture target DNA chain which methylation status is designed at different amount sites. On the electrode surface, the distribution density of the target CH3-hydrophobic sphere is different in the membrane microenvironment and the space resistance of the surface reaction medium is also different. Based on this mechanism, the electrochemical mathematical model was constructed for quantitative detection of DNA methylation level (5mC sites). Then, deeply parse response mechanism of pcPNA electrochemical analysis in liquid phase. With the development, the different amount sites methylation on dsDNA would be studied based on the pcPNA as probe with the characteristic of the double helix invasion. .Through this project, we hope to construct a novel original technical of Quantitative analyzing DNA methylation level, which would support the research of epigenetic and clinical quantitative detection of DNA methylation bias. On the other hand, the related basic theory will be clarified such as the optimum base spacing for electrochemical analysis of DNA methylation.