Tuneable graphene nanopores for single biomolecule detection

Abstract

Solid-state nanopores are promising candidates for next generation DNA and protein sequencing. However, once fabricated, such devices lack tuneability, which greatly restricts their biosensing capabilities. Here we propose a new class of solid-state graphene-based nanopore devices that exhibit a unique capability of self-tuneability, which is used to control their conductance, tuning it to levels comparable to the changes caused by the translocation of a single biomolecule, and hence, enabling high detection sensitivities. Our presented quantum simulation results suggest that the smallest amino acid, glycine, when present in water and in an aqueous saline solution can be detected with high sensitivity, up to a 90% change in conductance. Our results also suggest that passivating the device with nitrogen, making it an n-type device, greatly enhances its sensitivity, and makes it highly sensitive to not only the translocation of a single biomolecule, but more interestingly to intramolecular electrostatics within the biomolecule. Sensitive detection of the carboxyl group within the glycine molecule, which carries a charge equivalent to a single electron, is achieved with a conductance change that reaches as high as 99% when present in an aqueous saline solution. The presented findings suggest that tuneable graphene nanopores, with their capability of probing intramolecular electrostatics, could pave the way towards a new generation of single biomolecule detection devices.

Detection of DNA Bases via Field Effect Transistor of Graphene Nanoribbon With a Nanopore: Semi-Empirical Modeling

“…The designed sensor is enhanced by using nitrogen instead of hydrogen to passivate edge carbon atoms. The edge termination of graphene nanoribbons by nitrogen is noticed to be rich of electrons leading to n-type transistor behavior [43]. The edge structure and chemical termination is critical to get the desired device characteristics.…”

“…The nitrogen is considered as n-type donor. The nitrogen passivation was proofed to be electron rich resulting in n-type transistor behavior [43,44]. The nitrogen passivation results in excess free electrons which results in higher sensor current and better sensor performance.…”

“…The nitrogen passivation results in excess free electrons which results in higher sensor current and better sensor performance. Nitrogen passivation makes the sensor highly sensitive to the single molecule and to the intramolecular electrostatics within the molecule [43][44][45]. The fourth enhancement is studying the effect of noise factors such as sugar-phosphate backbone, nucleobases' translation, solution, and the neighboring nucleotides.…”

“…Theoretical work proofed that N-terminated pores enhance the single biomolecule detection and makes the sensor highly sensitive [43][44][45]. Most of the theoretical work conducted with nanoribbons was generated with simple model systems where the effect of solvent and ions are not considered [30,50,52].…”

Graphene Nanopores

“…The current trend towards nanotechnology and miniaturization of devices, ion transport through solid state nanopores is gaining attention [37][38][39][40][41]. 2D materials such as graphene play an important role for applications in nanofluidic device, biosensing, and DNA translocation [42][43][44][45].…”