Graphene Nanopore Devices for DNA Detection
M. Drndic and A.T. Johnson
Graphene is a thin, flexible material with interesting electronic and mechanical in which nanopores can be readily fabricated [Fischbein and Drndic, APL, 2008]. The electronic properties of conductive, carbon-based materials add functionality to future nanopore devices, which may be useful in future sequencing applications.
Large area graphene is grown using chemical vapor deposition (CVD) and is suspended over a micron-large hole in the silicon nitride membrane. Graphene nanopores are then drilled with a focused electron beam inside the transmission electron microscope (TEM). DNA molecules, inserted into the electrolyte, can be driven single file through such nanopores. As the molecules translocate, they block the flow of ions and are detected as a drop in the measured current.
We performed the first measurements of DNA translocation through graphene membranes as a demonstration of the feasibility of graphene-based nanopore devices. Coating the devices with a layer of oxide consistently reduced the nanopore noise level, and at the same time improved the robustness of the device in a manner that is compatible with future use as an electrically addressable nanopore platform.
Future work will focus on improving the overall reliability of these devices and on utilizing the conductivity of the graphene sheet to create devices with enhanced functionality.