Nanotransistor Boosts Sensitivity of Gene Sequencer

An individual genome is a sequence of about 3 billion nucleic acids, so even at high speeds, sequencing with a single nanopore would take too long. Practical sequencers would have to consist of multiple nanopores. However, in previous nanopore sequencer designs, electrical cross talk would occur between adjacent nanopores unless each one was secluded in its own chamber of solution. The Harvard version relies on the highly localized voltage, which is concentrated within just 30 to 50 nanometers of the opening, preventing cross talk with other nanopores as long as they are at least a few micrometers apart. Xie says the design should allow many nanopores to be grouped together on a single chip with shared solution chambers.

Joshua Edel, a senior lecturer in micro- and nanotechnology at Imperial College London, says the scheme could work. Because it measures conductance, ”ultimately this has the potential to achieve much higher resolution in order to distinguish different DNA bases when compared [with] the ionic current approach,” Edel says.

”I think this is an exciting and promising approach and a great direction to go into,” says Marija Drndic, associate professor of physics at the University of Pennsylvania. Both her group and Lieber’s are separately exploring the replacement of silicon nanowires in nanopore sequencers with graphene nanowires, which should have even higher conductance and therefore produce an even stronger signal.