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Phys. Rev. E 71, 041913 (2005) [5 pages]

Probing single DNA mobility with fluorescence correlation microscopy

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Svetlana A. Tatarkova1,2,* and David A. Berk2
1Department of Physics, University of Durham, Durham DH1 3LE, United Kingdom
2School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom

Received 20 August 2003; revised 27 September 2004; published 27 April 2005

Fluorescence correlation spectroscopy combined with microscopy (FCSM) is used to study the mobility of DNA fragments in aqueous solution and tissue models on the single molecule level. The effective hydrodynamic radius was measured for various lengths of ds-DNA chains and obeyed the theoretically inveterate [DNA length]0.5 relationship. Hindered diffusion of ds-DNA through the gel matrix of various densities is thought of as an extension of Kramer’s problem for a flexible polymer chain. With increasing DNA length the average barrier crossing time rises as [DNA length]2 and this agrees with theory predictions for polymer molecules surmounting an entropic barrier.

© 2005 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevE.71.041913
DOI:
10.1103/PhysRevE.71.041913
PACS:
87.64.−t, 32.50.+d, 82.35.−x, 82.37.−j

*Corresponding author. Electronic address: s.a.tatarkova@durham.ac.uk