| 1. |
- Janssen, Xander J. A., et al.
(författare)
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Rapid manufacturing of low-noise membranes for nanopore sensors by trans-chip illumination lithography
- 2012
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Ingår i: Nanotechnology. - : IOP Publishing: Hybrid Open Access. - 0957-4484 .- 1361-6528. ; 23:47
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the concept of nanopore sensing has matured from a proof-of-principle method to a widespread, versatile technique for the study of biomolecular properties and interactions. While traditional nanopore devices based on a nanopore in a single layer membrane supported on a silicon chip can be rapidly fabricated using standard microfabrication methods, chips with additional insulating layers beyond the membrane region can provide significantly lower noise levels, but at the expense of requiring more costly and time-consuming fabrication steps. Here we present a novel fabrication protocol that overcomes this issue by enabling rapid and reproducible manufacturing of low-noise membranes for nanopore experiments. The fabrication protocol, termed trans-chip illumination lithography, is based on illuminating a membrane-containing wafer from its backside such that a photoresist (applied on the wafers top side) is exposed exclusively in the membrane regions. Trans-chip illumination lithography permits the local modification of membrane regions and hence the fabrication of nanopore chips containing locally patterned insulating layers. This is achieved while maintaining a well-defined area containing a single thin membrane for nanopore drilling. The trans-chip illumination lithography method achieves this without relying on separate masks, thereby eliminating time-consuming alignment steps as well as the need for a mask aligner. Using the presented approach, we demonstrate rapid and reproducible fabrication of nanopore chips that contain small (12 mu m x 12 mu m) free-standing silicon nitride membranes surrounded by insulating layers. The electrical noise characteristics of these nanopore chips are shown to be superior to those of simpler designs without insulating layers and comparable in quality to more complex designs that are more challenging to fabricate.
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| 2. |
- Lundberg, Erik, 1981, et al.
(författare)
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Nanofabrication Yields. Hybridization and Click-Fixation of Polycyclic DNA Nanoassemblies
- 2011
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 5:9, s. 7565-7575
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the stepwise assembly of a fully addressable polycyclic DNA hexagon nanonetwork for the preparation of a lour-ring system, one of the biggest networks yet constructed from tripodal building blocks. We find that the yield exhibits a distinct upper level
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| 3. |
- Plesa, Calin, et al.
(författare)
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Direct observation of DNA knots using a solid-state nanopore
- 2016
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Ingår i: Nature Nanotechnology. - : NATURE PUBLISHING GROUP. - 1748-3387 .- 1748-3395. ; 11:12, s. 1093-1097
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Tidskriftsartikel (refereegranskat)abstract
- Long DNA molecules can self-entangle into knots. Experimental techniques for observing such DNA knots (primarily gel electrophoresis) are limited to bulk methods and circular molecules below 10 kilobase pairs in length. Here, we show that solid-state nanopores can be used to directly observe individual knots in both linear and circular single DNA molecules of arbitrary length. The DNA knots are observed as short spikes in the nanopore current traces of the traversing DNA molecules and their detection is dependent on a sufficiently high measurement resolution, which can be achieved using high-concentration LiCI buffers. We study the percentage of molecules with knots for DNA molecules of up to 166 kilobase pairs in length and find that the knotting occurrence rises with the length of the DNA molecule, consistent with a constant knotting probability per unit length. Our experimental data compare favourably with previous simulation based predictions for long polymers. From the translocation time of the knot through the nanopore, we estimate that the majority of the DNA knots are tight, with remarkably small sizes below 100 nm. In the case of linear molecules, we also observe that knots are able to slide out on application of high driving forces (voltage).
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| 4. |
- Pud, Sergii, et al.
(författare)
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Self-Aligned Plasmonic Nanopores by Optically Controlled Dielectric Breakdown
- 2015
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 15:10, s. 7112-7117
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Tidskriftsartikel (refereegranskat)abstract
- We present a novel cost-efficient method for the fabrication of high-quality self-aligned plasmonic nanopores by means of an optically controlled dielectric breakdown. Excitation of a plasmonic bowtie nanoantenna on a dielectric membrane localizes the high-voltage-driven breakdown of the membrane to the hotspot of the enhanced optical field, creating a nanopore that is automatically self-aligned to the plasmonic hotspot of the bowtie. We show that the approach provides precise control over the nanopore size and that these plasmonic nanopores can be used as single molecule DNA sensors with a performance matching that of TEM-drilled nanopores. The principle of optically controlled breakdown can also be used to fabricate nonplasmonic nanopores at a controlled position. Our novel fabrication process guarantees alignment of the nanopore with the optical hotspot of the nanoantenna, thus ensuring that pore-translocating biomolecules interact with the concentrated optical field that can be used for detection and manipulation of analytes.
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