(397e) Enhanced DNA Segmental Dynamics in Nanofluidic Channels

Investigations of DNA molecules in strongly confined environments depend on the increased DNA bending stiffness due to spatial restrictions.  We examine DNA molecules in nanofluidic devices using multi-scale computational models and how confinement causes non-monotonic change in DNA conformation, correlation lengths, and the segmental relaxation. Classical theories of deGennes and Odijk predict increased polymer relaxation time and polymer size in confinement with dimensions smaller than the radius of gyration. When the confinement dimensions become smaller than the polymer persistence length, the segmental correlation length conforms to the confinement geometry, leading to enhanced correlation lengths in the unconfined dimension but shortened correlation length in the confined dimension. We report the segmental relaxation times and correlation lengths in nano-confinements of height H, from H larger than the polymer radius of gyration Rg to smaller than the polymer persistence length P. A non-monotonic transition in the DNA relaxation time is observed in nanochannels, as found in previous experimental observations [1]. In contrast, no qualitative change of the segmental dynamics is observed in nanoslits [2,3]. The change in DNA correlation length is also characterized in semi-dilute and dense solutions, with implications for the mechanical properties for glass formation in thin films.

[1] W. Reisner et al., Physical Review Letters 94, 196101 (2005).

[2] PK Lin et al., Macromolecules 45, 2920 (2012).

[3] J. Tang et al., Macromolecules 43, 4368 (2010).