Stacked Graphene-Al₂O₃ Nanopore Sensors for Sensitive Detection of DNA and DNA–Protein Complexes

Abstract

We report the development of a multilayered graphene-Al2O3 nanopore platform for the sensitive detection of DNA and DNA-protein complexes. Graphene-Al2O3 nanolaminate membranes are formed by sequentially depositing layers of graphene and Al2O3 with nanopores being formed in these membranes using an electron-beam sculpting process. The resulting nanopores are highly robust, exhibit low electrical noise (significantly lower than nanopores in pure graphene), are highly sensitive to electrolyte pH at low KCl concentrations (attributed to the high buffer capacity of Al2O3) and permit the electrical biasing of the embedded graphene electrode, thereby allowing for three terminal nanopore measurements. In proof-of-principle biomolecule sensing experiments, the folded and unfolded transport of single DNA molecules and RecA coated DNA complexes could be discerned with high temporal resolution. The process described here also enables nanopore integration with new graphene based structures, including nanoribbons and nanogaps, for single molecule DNA sequencing and medical diagnostic applications.

Graphene nanodevices for DNA sequencing

“…Graphene nanopores particularly exhibit high low-frequency 1/f noise, which is likely of mechanical origin [41]. It may be possible to suppress this noise by reducing the area of the freestanding graphene [31], or by the use of multilayered structures [36,42,43]. Glass-based substrates may furthermore represent a good improvement, as low dielectric materials reduce the capacitive noise [44].…”

Graphene quantum point contact transistor for DNA sensing

“…Theoretical studies suggest that functionalized graphene nanopores can be used to differentiate passing ions, demonstrating the potential use of graphene membranes in nanofluidics and molecular sensing (13). In addition, its atomicscale thickness allows a molecule passing through it to be scanned at the highest possible resolution, and the feasibility of using graphene nanopores for DNA detection has been demonstrated experimentally (14)(15)(16)(17). Lastly, electrically active graphene can, in principle, both control and probe translocating molecules, acting as a gate as well as a charge sensor, which passive, oxide-based nanopore devices are incapable of doing.…”

Nanoporentechniken zur Sequenzierung und Detektion von Nukleinsäuren

“…Graphen ist aufgrund seiner außerordentlich kleinen Schichtdicke (0.34-0.68 nm), die mit dem Abstand zwischen benachbarten Nukleotiden in ssDNA vergleichbar ist (0.32-0.52 nm), schnell ins Rampenlicht der Forscher gerückt. [44] Die erste einzelne Nanopore in suspendiertem Graphen wurde von Fischbein und Drndic hergestellt. [45] Später wurden einzelne dsDNA-Moleküle durch Graphen-Nanoporen gesteuert (Abbildung 4 a,b) [46] und Translokationssignale der DNA erhalten, was das enorme Potential von Graphen-Nanoporen in der DNA-Sequenzierung bestätigte.…”