DNA Sensing Using Nanocrystalline Surface-Enhanced Al2O3 Nanopore Sensors

Advanced Functional Materials (Impact Factor: 10.44). 04/2010; 20(8). DOI: 10.1002/adfm.200902128

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 transforms the local nanostructure and morphology of the pore from an amorphous, stoichiometric structure (O to Al ratio of 1.5) to a heterophase crystalline network, deficient in O (O to Al ratio of ≈0.6). Direct metallization of the pore region is observed during irradiation, thereby permitting the potential fabrication of nanoscale metallic contacts in the pore region with application to nanopore-based DNA sequencing. Dose-dependent phase transformations to purely γ and/or α-phase nanocrystallites are also observed during pore formation, allowing for surface-charge engineering at the nanopore/fluid interface. DNA transport studies reveal 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 make them ideal for the detection and analysis of single-stranded DNA, double-stranded DNA, RNA secondary structures, and small proteins. These nanoscale sensors may also serve as useful tools in studying the mechanisms driving biological processes including DNA–protein interactions and enzyme activity at the single-molecule level.

Download full-text


Available from: Jian-Min Zuo, Jul 02, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Solid-state nanopores have emerged as sensors for single molecules and these have been employed to examine the biophysical properties of an increasingly large variety of biomolecules. Herein we describe a novel and facile approach to precisely adjust the pore size, while simultaneously controlling the surface chemical composition of the solid-state nanopores. Specifically, nanopores fabricated using standard ion beam technology are shrunk to the requisite molecular dimensions via the deposition of highly conformal pulsed plasma generated thin polymeric films. The plasma treatment process provides accurate control of the pore size as the conformal film deposition depends linearly on the deposition time. Simultaneously, the pore and channel chemical compositions are controlled by appropriate selection of the gaseous monomer and plasma conditions employed in the deposition of the polymer films. The controlled pore shrinkage is characterized with high resolution AFM, and the film chemistry of the plasma generated polymers is analyzed with FTIR and XPS. The stability and practical utility of this new approach is demonstrated by successful single molecule sensing of double-stranded DNA. The process offers a viable new advance in the fabrication of tailored nanopores, in terms of both the pore size and surface composition, for usage in a wide range of emerging applications.
    Nanotechnology 06/2011; 22(28):285304. DOI:10.1088/0957-4484/22/28/285304
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Graphene has recently emerged as an important and exciting material. Inspired by its outstanding properties, many researchers have extensively studied graphene-related materials both experimentally and theoretically. Porous graphene is a collection of graphene-related materials with nanopores in the plane. Porous graphene exhibits properties distinct from those of graphene, and it has widespread potential applications in various fields such as gas separation, hydrogen storage, DNA sequencing, and supercapacitors. In this review, we summarize recent progress in studies of the properties, preparation, and potential applications of porous graphene, and show that porous graphene is a promising material with great potential for future development.
    Chinese Science Bulletin 08/2012; 57(23). DOI:10.1007/s11434-012-5121-3
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on DNA translocations through nanopores created in graphene membranes. Devices consist of 1-5 nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. However, ionic current noise levels are several orders of magnitude larger than those for silicon nitride nanopores. These fluctuations are reduced with the atomic-layer deposition of 5 nm of titanium dioxide over the device. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore.
    Nano Letters 08/2010; 10(8):2915-21. DOI:10.1021/nl101046t