Conformation and solvation shell of stearoyl-modified hyaluronic-acid oligosaccharides in binary solvents.

Hyaluronic acid (HA) is a natural hydrophilic polysaccharide with wide applications in healthcare and cosmetics, often substituted by non-polar aliphatic residues, giving it an amphiphilic nature. The stability of secondary structures of these molecules depends on the length of the HA chain, the type of the substituent, the degree of substitution and the composition of the used solvent - its influence is investigated in this molecular-dynamics study. Sole 18-carbon saturated aliphatic chains and their couples are simulated in three solvent systems: water, water : 1,4-dioxane and water : tert-butanol binary mixtures containing varying NaCl concentrations, then the simulations of several variants of substituted HA chains follow. Besides other tiny factors, the simulations indicate that a strong ability to separate solvent components makes the molecules inert with respect to mutual interactions, while a solvent with a lower separation ability can stabilize them better.