Billingsley, DJ, Lee, AJ, Johansson, NAB et al. (5 more authors) (2014) Patchiness of ion-exchanged mica revealed by DNA binding dynamics at short length scales. Nanotechnology, 25 (2). 02570. ISSN 1361-6528
Abstract
The binding of double-stranded (ds) DNA to mica can be controlled through ion-exchanging the mica with divalent cations. Measurements of the end-to-end distance of linear DNA molecules discriminate whether the binding mechanism occurs through 2D surface equilibration or kinetic trapping. A range of linear dsDNA fragments have been used to investigate length dependences of binding. Mica, ion-exchanged with Ni(II) usually gives rise to kinetically trapped DNA molecules, however, short linear fragments (<800 bp) are seen to deviate from the expected behaviour. This indicates that ion-exchanged mica is heterogeneous, and contains patches or domains, separating different ionic species. These results correlate with imaging of dsDNA under aqueous buffer on Ni(II)-mica and indicate that binding domains are of the order of 100 nm in diameter. Shorter DNA fragments behave intermediate to the two extreme cases of 2D equilibration and kinetic trapping. Increasing the incubation time of Ni(II) on mica, from minutes to hours, brings the conformations of the shorter DNA fragments closer to the theoretical value for kinetic trapping, indicating that long timescale kinetics play a role in ion-exchange. X-ray photoelectron spectroscopy (XPS) was used to confirm that the relative abundance of Ni(II) ions on the mica surface increases with time. These findings can be used to enhance spatial control of binding of DNA to inorganic surfaces with a view to patterning high densities arrays.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2014 IOP Publishing Ltd. This is an author produced version of a paper published in Nanotechnology. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | atomic force microscopy; DNA; mica; nickel; phase separation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Dentistry (Leeds) > Oral Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Oct 2014 09:24 |
Last Modified: | 21 Apr 2015 02:10 |
Published Version: | http://dx.doi.org/10.1088/0957-4484/25/2/025704 |
Status: | Published |
Publisher: | IOP Publishing |
Identification Number: | 10.1088/0957-4484/25/2/025704 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80884 |