DNA Sensing Using Nanocrystalline Surface‐Enhanced Al₂O₃ Nanopore Sensors

Abstract

A new solid-state, Al2O3 nanopore sensor with enhanced surface properties for the real-time detection and analysis of individual DNA molecules is reported. Nanopore formation using electron beam based decomposition transformed the local nanostructure and morphology of the pore from an amorphous, stoichiometric structure (O to Al ratio of 1.5) to a hetero-phase crystalline network, deficient in O (O to Al ratio of ~0.6). Direct metallization of the pore region was observed during irradiation, thereby permitting the potential fabrication of nano-scale metallic contacts in the pore region with potential application to nanopore-based DNA sequencing. Dose dependent phase transformations to purely γ and/or α-phase nanocrystallites were also observed during pore formation allowing for surface charge engineering at the nanopore/fluid interface. DNA transport studies revealed an order of magnitude reduction in translocation velocities relative to alternate solid-state architectures, accredited to high surface charge density and the nucleation of charged nanocrystalline domains. The unique surface properties of Al2O3 nanopore sensors makes them ideal for the detection and analysis of ssDNA, dsDNA, RNA secondary structures and small proteins. These nano-scale sensors may also serve as a useful tool in studying the mechanisms driving biological processes including DNA-protein interactions and enzyme activity at the single molecule level.

Detecting the translocation of DNA through a nanopore using graphene nanoribbons

“…The pores used in our experiments were drilled in a SiN x membrane onto which a layer of Al 2 O 3 had been deposited. The presence of the thin alumina layer on the walls of the pore changes the surface charge from negative to positive, allowing current drops to be negative even at very low ionic strengths (10 mM KCl) 29,30 . Interestingly, we observed both dips and spikes in the electrical current flowing through the GNR.…”

Rapid Ultrasensitive Single Particle Surface-Enhanced Raman Spectroscopy Using Metallic Nanopores

“…Nanopore sensing has recently become a highly regarded technique for applications where single analyte analysis is required 1,2,3,4 . A number of nanopore platforms exist, e.g.…”

Porous graphene: Properties, preparation, and potential applications

“…Many porous membrane materials such as SiO 2 [56], Al 2 O 3 [57], and Si 3 N 4 [58] have been fabricated to explore their possible use for DNA sequencing. However, the major barricade to achieving high resolution is the finite length of the channel through the pore, which makes it difficult to distinguish the different current signals of the four nucleotides.…”