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Fine tuning of nanopipettes using atomic layer deposition for single molecule sensing
File(s)
ALD V8.docx (1.83 MB)
Accepted version
Author(s)
Sze, JYY
Kumar, S
Ivanov, AP
Oh, SH
Edel, JB
Type
Journal Article
Abstract
Nanopipettes are an attractive single-molecule tool for identification and characterisation of nucleic acids and proteins in solutions. They enable label-free analysis and reveal individual molecular properties, which are generally masked by ensemble averaging. Having control over the pore dimensions is vital to ensure that the dimensions of the molecules being probed match that of the pore for optimization of the signal to noise. Although nanopipettes are simple and easy to fabricate, challenges exist, especially when compared to more conventional solid-state analogues. For example, a sub-20 nm pore diameter can be difficult to fabricate and the batch-to-batch reproducibility is often poor. To improve on this limitation, atomic layer deposition (ALD) is used to deposit ultrathin layers of alumina (Al2O3) on the surface of the quartz nanopipettes enabling sub-nm tuning of the pore dimensions. Here, Al2O3 with a thickness of 8, 14 and 17 nm was deposited onto pipettes with a starting pore diameter of 75 ± 5 nm whilst a second batch had 5 and 8 nm Al2O3 deposited with a starting pore diameter of 25 ± 3 nm respectively. This highly conformal process coats both the inner and outer surfaces of pipettes and resulted in the fabrication of pore diameters as low as 7.5 nm. We show that Al2O3 modified pores do not interfere with the sensing ability of the nanopipettes and can be used for high signal-to-noise DNA detection. ALD provides a quick and efficient (batch processing) for fine-tuning nanopipettes for a broad range of applications including the detection of small biomolecules or DNA-protein interactions at the single molecule level.
Date Issued
2015-06-03
Date Acceptance
2015-06-04
Citation
Analyst, 2015, 14, pp.4828-4834
URI
DOI
ISSN
0003-2654
Publisher
Royal Society of Chemistry
Start Page
4828
End Page
4834
Journal / Book Title
Analyst
Volume
14
Copyright Statement
© The Royal Society of Chemistry 2015. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Publication Status
Published