本项目针对超痕量环境污染物全氟羧酸（PFCAs）异构体的精准检测需求，计划建立一种基于纳米孔道电化学传感的单分子分析新方法。通过构建具有高空间分辨能力的蛋白质纳米孔道传感界面，显著提升特征电流信号对PFCAs结构的解析精度；合理设计检测识别探针的功能结构域，诱导增强孔道对PFCAs-探针复合体的电泳捕获作用，有效压缩PFCAs结构鉴定所需时间；调控电解液组分以增大孔道捕获半径、降低入孔势垒，大幅缩短前后两次PFCAs异构体鉴定的间隔时间。在不超过10分钟的响应时间内，实现对多种不同链长、不同种类PFCAs异构体（直链/支链、手性）的定量分析，方法检出限不超过1皮摩尔/升，浓度检测线性范围达到6个数量级。综上，本项目提出的纳米孔道单分子检测新方法为精准测定不同介质中PFCA异构体的浓度提供了新思路，同时也为科学开展PFCAs污染物源解析、迁移转换规律、分子毒理学等研究奠定了坚实基础。

In order to meet the requirement of precision detection of perfluorinated carboxylic acids (PFCAs) isomers, an emerging type of environmental pollutants at ultra-low concentrations, this project aims to develop a new single-molecule analytical method based on nanopore electrochemical sensing. A protein nanopore sensing interface with high spatial resolution will first be built to significantly improve the resolving power of current signals on PFCAs structures. In the meantime, a detection probe with rationally designed structural functional / structural domains is applied to induce the electrophoretic trapping of the PFCA/probe hybrids and effectively reduce the amount of dwell time required for PFCAs isomeric identification. Finally, the chemical composition of electrolytes is further modified to enhance the capture frequency of PFCAs isomers by increasing the effective capture radius of a nanopore and lowering the entry barrier into a nanopore. It is expected that a wide range of constitutional and stereo- isomers of PFCAs with different chain length can be quantified simultaneously. The resulting method detection limit is no greater than 1 pM, and a linear detection range is reached within six order of magnitude. To summarize, the nanopore single-molecule sensing proposed in this project offers a new way to precisely detect the concentration of PFCAs in a variety of matrix and is highly useful in other research fields of PFCAs study.