title: Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection.
abstract: We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.
authors.affiliation: Chongqing Key Laboratory of Multi-scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China.
authors.forename: Yunsheng
authors.initials: Y
authors.lastname: Deng
authors.forename: Qimeng
authors.initials: Q
authors.lastname: Huang
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.forename: Daming
authors.initials: D
authors.lastname: Zhou
authors.forename: Cuifeng
authors.initials: C
authors.lastname: Ying
authors.forename: Deqiang
authors.initials: D
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry; D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry*; D006371:Helium / Q000737:chemistry*; D007477:Ions; D008853:Microscopy / Q000295:instrumentation*; D058608:Nanopores
chemical_list: D004277:DNA, Single-Stranded; D007477:Ions; D006371:Helium; D006108:Graphite