Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
ACS Nano. 2013 Jun 25;7(6):5008-16. doi: 10.1021/nn4003665. Epub 2013 Jun 6.
Graphene is a unique material with a thickness as low as a single atom, high in-plane conductivity and a robust lattice that is self-supporting over large length scales. Schematically, graphene is an ideal solid-state material for tuning the properties of a nanopore because self-supported sheets, ranging from single to multiple atomic layers, can create pores with near-arbitrary dimensions which can provide exquisite control of the electric field drop within the pore. In this study, we characterize the drilling kinetics of nanopores using a thermionic electron source and various electron beam fluxes to minimize secondary hole formation. Once established, we investigated the use of multilayer graphene to create highly tailored nanostructures including nanopores with graphite polyhedral crystals formed around the nanopore edge. Finally, we report on the translocation of double stranded and single stranded DNA through such graphene pores and show that the single stranded DNA translocates much slower allowing detection of extremely short fragments (25 nucleotides in length). Our findings suggest that the kinetic and controllable properties of graphene nanopores under sculpting conditions can be used to further enhance the detection of DNA analytes.
石墨烯是一种独特的材料，其厚度低至单层原子，面内电导率高，晶格坚固，在较大的长度尺度上能够自支撑。从示意图上看，石墨烯是一种理想的固态材料，可用于调整纳米孔的性质，因为自支撑的薄片（从单层到多层原子层）可以创建具有近乎任意尺寸的孔，从而可以对孔内的电场下降进行精确控制。在这项研究中，我们使用热电子源和各种电子束通量来表征纳米孔的钻孔动力学，以最小化二次孔的形成。一旦建立起来，我们研究了使用多层石墨烯来创建高度定制的纳米结构，包括在纳米孔边缘形成石墨多面体晶体的纳米孔。最后，我们报告了双链和单链 DNA 通过这种石墨烯孔的迁移情况，并表明单链 DNA 的迁移速度要慢得多，从而可以检测到极短的片段（长度为 25 个核苷酸）。我们的研究结果表明，在雕刻条件下，石墨烯纳米孔的动力学和可控性质可用于进一步提高 DNA 分析物的检测能力。
