Dynamics and complex formation in charged and uncharged Ficoll70 solutions

TL;DR

This study uses PFG NMR to investigate the diffusion and interactions of charged and uncharged Ficoll70 solutions, revealing non-ideal behavior, clustering, and bound water layers in these polysaccharide suspensions.

Contribution

It provides new quantitative insights into the diffusion, clustering, and structural properties of Ficoll70 solutions, including the effects of charge and the presence of bound water.

Findings

Ficoll70 exhibits non-ideal diffusion behavior with signs of softness and attraction.

The solution contains monomers and clusters, quantifiable via NMR.

Evidence of a bound water layer around Ficoll70 particles.

Abstract

We apply pulsed-field-gradient NMR (PFG NMR) technique to measure the translational diffusion for both uncharged and charged polysaccharide (Ficoll70) in water. Analysis of the data indicate that NMR signal attenuation above a certain packing fraction can be adequately fitted with a bi-exponential function. The self-diffusion measurements show also that the Ficoll70, an often-used compact, spherical polysucrose molecule, is itself non-ideal, exhibiting signs of both softness and attractive interactions in the form of a stable suspension consisting of monomers and clusters. Further, we can quantify the fraction of monomer and cluster. This work strengthens the picture of the existence of a bound water layer within and around a porous Ficoll70 particle.