Dynamical stiffening of dsDNA confined and stretched in a nanochannel

Abstract The internal dynamics of double-stranded DNA (dsDNA) confined within channels of diameters ranging from the persistence length to twice that length were investigated using fluorescence microscopy. By analysing spatiotemporal intensity fluctuations, we derived the intermediate dynamic structure factor. The structure factor consistently exhibited behaviour characteristic of Rouse dynamics, regardless of the channel diameter. Notably, as the channel diameter decreased, the DNA molecules became increasingly elongated along the channel, leading to shorter relaxation times. These findings indicate a dynamic stiffening effect, where the effective spring constant of a stretched polymer chain increases. We propose that this effect has significant implications for controlling DNA motion in biological and biotechnological applications.