Orientation Kinetics of Chiral-Nematic N* Domains in Suspensions of Charged DNA Rods

Abstract

Many biological systems exhibit natural regulation mechanisms as necessary functions. Proteins, peptides, charged receptors, RNAs, and DNAs clearly demonstrate such varieties of structural dynamics in their biocomplexity. To understand the proper structural functionality of biomolecules, this requires integrated information from initiation, regulation, transfer and transport to desirable sustainable processes. Here, we demonstrate the orientation kinetics of stable chiral-nematic (N*) domains that are consistently formed in the suspensions of charged DNA rods at low ionic strengths. This is enhanced by large access of released dissociated condensed ions and the mobile diffusive ions of DNA rods, acting onto the perpendicular motions of the DNA rods in bulk. The quantification of collective orientations for these interacting charged DNA rods is extracted by image-time correlation (ITC) performed in Fourier transforms (FTs) for overall spectral density distributions. Three distinguishable length scales are clearly shown corresponding to the relevant motion of the N* domain in parallel, perpendicular and the optical pitch within the domains as well as the kinetics of local distributions in FTs. Particularly strong concentration transitions are confirmed by replica symmetry breaking of elastic deformations in N* domains in terms of the average twist angle and the order parameter. This work can be interesting for sufficient cooling of the given concentration of charged DNA rods, at low ionic strengths (below the critical value), mimicking super-cooled liquid and orientation glass in other biomacromolecules.