Nanoelectronics: Nanoribbons on the edge.

MIT team observed that although the ion permeability of an intact graphene membrane was negligible compared with that of a membrane that contained a nanopore, it was not zero and it was different for different cations, which indicates that electrolyte–graphene interactions need to be taken into account6. Evidence of DNA– graphene interactions was also observed6–8. These interactions will need to be carefully understood if an ionic-current-based DNA sequencing algorithm is to be employed. Perhaps the most striking question that arises from these reports relates to the dimensionality of the graphene pore: the pore was seen to behave as both a cylinder of finite length (with its conductance being proportional to the square of the diameter)7 and as an infinitesimally thin circular aperture (with conductance proportional to diameter)6. This work on graphene nanopores is certain to be the precursor to further studies in a variety of fields. Within the scope of nanopore sensing, there are numerous avenues to explore using the graphene itself as an electrode to control the local electric potential and translocation rates, or to monitor the transverse conductance of individual nucleotides as they pass through a pore9. Previous theoretical work suggests that the latter technique, if used in the proper geometry, could provide DNA sequencing with a 0% error rate10. Combined with recent advances in the production of large-area high-quality graphene (sheets with up to a 30-inch diagonal)4, the results open the door to a host of interesting explorations including the development of new membrane systems for biosensing. ❐