基于石墨烯纳米孔器件的DNA单分子探测研究

Single-molecule detection based on nanopores has attracted intensive research interest in interdisciplinary field because they can realize biomolecule structure measurement on single-molecule level. DNA sequencing based on solid-state nanopores has become one of the most promising candidates in future third generation rapid and cost-effective gene sequencing research, which aims to fulfill one person genome sequencing in 24 hours by less than 1000 US dollars. There are two main challenges remaining in this field: one is the supporting membrane for nanopores is too thick to read single base level (low spatial resolution); second is that DNA translocation speed through nanopores is too fast to reach the device detection limit (low time resolution).In this project, we combine graphene and nanopore together to make graphene nanopores. Taking advange of the ultrathin single atomic layer thickness of graphene, plus its excellent mechanical and electric properties, spatial resolution of DNA single-molecule detection based on graphene nanopores can be greatly improved. More importantly, we are going to innovatively introduce pressure as counter flow field to slow down the speed of DNA translocation through nanopores. In this way, time resolution of DNA detection based on graphene nanopores can be enhanced significantly as well. Counter pressure flow will effectively decrease the total force on DNA in nanopore, thus it can effectively adjust the translocation speed of DNA inside nanopores. By reasonably tuning the electric field and pressure counter flow field, DNA single-molecule detection, trap, recapture or even manupilation should be realized, which is extremely important for future DNA sequencing applications.

纳米孔由于其可以在单分子量级上实现对生物分子结构的测量，引发了前沿交叉领域极大的关注与科研热情。基于固态纳米孔的DNA测序成为目前国际第三代基因测序仪（旨在24小时之内用1000美金完成对人体基因测序）研制中最有力的竞争者之一，成为国际上基础研究和应用探索的热点。目前此领域存在的最重要的两大问题是：纳米孔支撑膜过厚（空间分辨率过低）和DNA分子穿孔速度过快（时间分辨率过低）。本项目巧妙地将石墨烯与纳米孔结合起来，利用石墨烯超薄的单原子层厚度，优异的力学和电学性能大大提高基于石墨烯纳米孔对DNA进行单分子探测的空间分辨率。在此基础上，创新性的引入反向压强作为减速力场，用于减慢DNA穿过纳米孔的速度，从而大幅提高基于固态纳米孔DNA单分子探测的时间分辨率。通过调节电场与压强场的大小，预期可以实现对DNA的单分子探测，捕获，操控，为最终实现基于石墨烯纳米孔的基因测序打下坚实的基础。

纳米孔由于其可以在单分子量级上实现对生物分子结构的测量，引发了前沿交叉领域极大的关注与科研热情。基于固态纳米孔的DNA测序成为目前国际第三代基因测序仪（旨在24小时之内用1000美金完成对人体基因测序）研制中最有力的竞争者之一，成为国际上基础研究和应用探索的热点。目前此领域存在的最重要的两大问题是：纳米孔支撑膜过厚（空间分辨率过低）和DNA分子穿孔速度过快（时间分辨率过低）。利用本项目的顺利实施建立了固态纳米孔传感器单分子检测实验研究平台；发展了一整套可控精确加工纳米孔传感器的方法；自主制备的纳米孔传感器可顺利完成超过一万次的DNA单分子探测（达到国际领先水平）；并在纳米孔几何构型控制与DNA受力模拟方面取得系列进展。针对纳米孔探测空间分辨率低这一难题，发明了一套快速、高效、精确制备超薄二维原子层材料纳米孔传感器的新方法，首次提出并实现了超薄氮化硼纳米孔传感器对DNA的单分子检测，达到国际最高空间分辨率，受到国内外同行与网站广泛关注。针对纳米孔探测时间分辨率低这一难题，提出将压强引入到纳米孔中来实现驱动力与信号读取彻底分离的新方法，有效减慢了DNA穿孔速度，大幅提高探测时间分辨率3个数量级，并首次利用纳米孔传感器实现了对中性分子的单分子探测以及长度差仅为600个碱基对的不同长度DNA分辨，显著扩展了纳米孔生物传感器的探测应用范围。已授权的4项发明专利直接针对三代测序产业的具体应用，其中与哈佛大学共同申请的国际专利已许可给目前国际上最大的第三代测序仪研究公司－牛津纳米孔集团进行有偿使用。

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