Slowing down of water dynamics in disaccharide aqueous solutions
Abstract
The dynamics of water in aqueous solutions of three homologous disaccharides, namely trehalose, maltose and sucrose, has been analyzed by means of molecular dynamics simulations in the 0-66 wt % concentration range. The low-frequency vibrational densities of states (VDOS) of water were compared with the susceptibilities chi" of 0-40 wt % solutions of trehalose in D2O obtained from complementary Raman scattering experiments. Both reveal that sugars significantly stiffen the local environments experienced by water. Accordingly, its translational diffusion coefficient decreases when the sugar concentration increases, as a result of an increase of water-water hydrogen bonds lifetimes and of the corresponding activation energies. This induced slowing down of water dynamics, ascribed to the numerous hydrogen bonds that sugars form with water, is strongly amplified at concentrations above 40 wt % by the percolation of the hydrogen bond network of sugars, and may partially explain their well-known stabilizing effect on proteins in aqueous solutions.
Keywords
Cite
@article{arxiv.1005.5327,
title = {Slowing down of water dynamics in disaccharide aqueous solutions},
author = {Adrien Lerbret and Frederic Affouard and Patrice Bordat and Alain Hedoux and Yannick Guinet and Marc Descamps},
journal= {arXiv preprint arXiv:1005.5327},
year = {2015}
}
Comments
14 pages, 4 figures, accepted in Journal of Non-Crystalline Solids (proceedings of the conference IDMRCS6)