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Updated: Aug 6, 2026

Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
Refusing to twist: demonstration of a line hexatic phase in DNA liquid crystals
1Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003 and NICHD/LPSB, National Institutes of Health, Building 12A/2041, Bethesda, Maryland 20892-5626, USA.
Abstract:
We report conclusive high resolution small angle x-ray scattering evidence that long DNA fragments form an untwisted line hexatic phase between the cholesteric and the crystalline phases. The line hexatic phase is a liquid-crystalline phase with long-range hexagonal bond-orientational order, long-range nematic order, but liquidlike, i.e., short-range, positional order. So far, it has not been seen in any other three dimensional system. By line-shape analysis of x-ray scattering data we found that positional order decreases when the line hexatic phase is compressed. We suggest that such anomalous behavior is a result of the chiral nature of DNA molecules.
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