A team of researchers from Delft University of Technology have developed a new type of nanopore device that may provide the basis of an improved method for sequencing DNA.
In a paper entitled, ‘DNA Translocation through Graphene Nanopores’, published online in Nano Letters, they report a novel technique for fabricating nanopores in a layer of graphene, a carbon material with a thickness of only 1 atom, and then detecting the motion of individual DNA molecules as they travel through these holes.
Existing solid-state nanopores suffer from the drawback that the channel constituting the pore is long, at 100 times the distance between two bases in a DNA molecule (which is 0.5 nm for single-stranded DNA). The researchers have now provided proof-of-concept for using ultrathin nanopores fabricated in graphene monolayers for detecting single molecules of DNA as they pass through the pore.
The pores are obtained by placing a graphene flake over a microsize hole in a silicon nitride membrane (a material currently used to fashion nanopores) and drilling a nanosize hole in the graphene using an electron beam. As individual DNA molecules pass through the pore, characteristic temporary conductance changes are observed in the ionic current through the nanopore. This sets the stage for future single-molecule genomic screening devices.