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Comparison of the coil-stretch transition of linear and circular DNA in planar extensional flow

Li, Yanfei and Brockman, Christopher and Yates, Daniel and McKenna, Gregory and Schroeder, Charles and San Francisco, Michael and Kornfield, Julia A. and Anderson, Rae (2014) Comparison of the coil-stretch transition of linear and circular DNA in planar extensional flow. Abstracts of Papers of the American Chemical Society, 247 . 420-PMSE. ISSN 0065-7727.

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Understanding the elongational flow behavior of macromols. is of great interest due to its application in turbulent drag redn. and fiber spinning. It was predicted by P.G. De Gennes in 1974 that above a crit. extension rate, a coiled polymer would experience a coil-stretch transition (CST) to adopt a relatively open configuration. This has been proven to be true for linear polymers by both birefringence and microfluidic techniques. On the other hand, understanding the extensional behavior of ring-like polymers is vital due to its application in the gene therapy studies using plasmid DNA. However, it remains unknown whether ring-like polymers exhibit a similar transition, and, if so, how their CST behavior compares with that of linear counterparts. In the present investigation, we examine the dynamics of large ring-like and linear DNA mols. with the goal of providing fundamental data related to the coil-stretch transition (CST), hysteresis in CST, and mol. individualism. To do this, we combined biol. synthesis of DNA mols. following the procedures of D.E. Smith and coworkers with direct imaging of fluorescently labeled DNA at the stagnation point in a novel microfluidic device that has a cross-slot design to develop a stagnation point extensional flow that permits direct imaging of the fluorescently labeled DNA. Preliminary results show for 45 kbp DNAs that both cyclic and linear DNA exhibit CST at a Weissenberg no. close to 0.5, corresponding to a faster extension rate for the ring-like DNA (which has a relaxation time three times faster than a linear DNA of the same mol. wt.). Results will be presented for a range of DNA and circular DNA contour lengths.

Item Type:Article
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McKenna, Gregory0000-0002-5676-9930
Kornfield, Julia A.0000-0001-6746-8634
Additional Information:© 2014 American Chemical Society.
Record Number:CaltechAUTHORS:20150316-093513196
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55776
Deposited By: Tony Diaz
Deposited On:16 Mar 2015 17:42
Last Modified:09 Mar 2020 13:19

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