Boosting DNA Recognition Sensitivity of Graphene Nanogaps through Nitrogen Edge Functionalization

Abstract

One of the challenges for next generation DNA sequencing is to have a robust, stable, and reproducible nanodevice. In this work, we propose how to improve the sensing of DNA nucleobase using functionalized graphene nanogap as a solid state device. Two types of edge functionalization, namely, either hydrogen or nitrogen, were considered. We showed that, independent of species involved in the edge passivation, the highest-to-lowest order of the nucleobase transmissions is not altered, but the intensity is affected by several orders of magnitude. Our results show that nitrogen edge tends to p-dope graphene, and most importantly, it contributes with resonance states close to the Fermi level, which can be associated with the increased conductance. Finally, the translocation process of nucleobases passing through the nanogap was also investigated by varying their position from a certain height (from +3 to −3 Å) with respect to the graphene sheet to show that nitrogen-terminated sheets have enhanced sensitivity, as moving the nucleobase by approximately 1 Å reduces the conductance by up to 3 orders of magnitude.

DNA-graphene interactions during translocation through nanogaps

“…Since both Δ G and τ vary more than for circular graphene nanopores, the process for the events described here is fundamentally different, and it is not surprising that the trend Δ G ∝ 1/ τ is not followed. Finally, the interaction between the graphene edge and the DNA molecule may also be affected by the nature of the edge, and harnessing this interaction may enhance performance of DNA sequencing devices built on this principle [ 18 , 31 , 32 ].…”

DNA Sequencing: Current State and Prospects of Development

“…Two offset windows are advanced: lower (1 -1.2 V) and higher (2.7 -3 V), where it is possible to uniquely identify all four bases from the current traces, although a higher sensitivity is obtained in the higher voltage window. Ways to improve the sensitivity of the DNA-nucleotide base using functionalized graphene nanogap as a solid-state device was analyzed in [45]. The appropriate translocation rate of the base molecule provides a time-dependent function of interaction change inside of interaction interval of each individual base with graphene nanopore.…”

Graphene and Graphene-Based Nanomaterials for DNA Detection: A Review

“…There are some researches focusing on the influence factors of this approach and trying to improve the sensitivity, selectivity and efficiency of this device. It was indicated that the best discrimination ability can be achieved with a nanogap distance as 1.1 nm [ 79 ], and edge functionalization of hydrogen [ 77 ], phosphate-group-grabbing guanidinium ion [ 80 ] and nitrogen [ 81 ] can be used to reduce the current fluctuation, enhance the DNA recognition sensitivity, and even slow down the translocation speed of DNA. Furthermore, the graphene-hBN heterostructure nanogap was recently proposed as an alternative for DNA sequencing, which could offer high sensitivity [ 82 ].…”