Potential of mean force between two ions in a sucrose rich aqueous solution

Molecular dynamics and potential of mean force (PMF) calculations are performed on an aqueous sucrose solution of an ion pair to investigate how ionic interactions are modified by the presence of the sugar. The presence of sucrose is shown to deepen the PMF minimum for Na–Cl ion pair, with an overall behavior compatible with continuum electrostatics. The comparison of PMF and hydration of the Na–Cl ion pair in pure water and in concentrated aqueous sucrose solution clearly reveals the preferential hydration of ions. The relevance of these results to biological systems is discussed.