Comment on `Nanoconfinement-enhanced conformational response of single DNA molecules to changes in ionic environment'

TL;DR

This paper challenges previous claims by arguing that DNA behavior in nanochannels at low ionic strength is better explained by entropic depletion theory rather than excluded volume effects, refining understanding of DNA conformational responses.

Contribution

It clarifies the role of excluded volume effects versus entropic depletion in DNA behavior within nanochannels at low ionic strength.

Findings

Excluded volume effects are not significant at low ionic strength.

DNA extension data align with Odijk's entropic depletion theory.

Revises previous interpretations of DNA conformational responses.

Abstract

In the present Comment we show that, contrary to the recent findings of Reisner et al. [Phys. Rev. Lett. 99, 058302 (2007)], the excluded volume effect does not play an important role in determining DNA behavior in nanochannels at low ionic strength. We argue that the DNA extension data are described very well without the notion of an effective polymer width using the entropic depletion theory due to Odijk.