Novel Nanopore Sensor for DNA Sequencing: Many label-free nanopore-based DNA sequencing methods have been proposed because of their potential for high throughput and possible large-scale integration with standard semiconductor technology. At the IEDM, Hitachi researchers will describe a way to identify the four nucleotides that make up the DNA molecule, using a novel side-gated ultrathin field-effect transistor (FET) containing a nanopore (4-9 nm diameter), through which DNA strands pass. The nanopore sits between the transistor’s control gate and channel, to which it is adjacent. When voltage is applied to the control gate, channel current is generated near the edge of the channel close to the nanopore. This current is then modulated by the electrical charges each DNA nucleotide produces as it passes through the nanopore. Spatial resolution is determined by channel thickness, and the 55nm-thick channel has an ultrathin conductive layer (2-4nm) for high sensitivity. The device operated successfully in air, water and a KCl solution.
The image above left shows a schematic of the device; the middle image is a TEM electron microscope view of it; and the image on the right is a magnified view of the nanopore.
(Paper 14.3, “A Novel Side-Gated Ultrathin-Channel Nanopore FET (SGNAFET) Sensor for Direct DNA Sequencing,” I. Yanagi et al, Hitachi)