Hydrogen Bonding Analysis of α, α-trehalose Aqueous Solutions

Abstract

Molecular dynamics simulations were carried out to model aqueous solution with different concentration of α,α-trehalose, one kind of nonreducing sugars possessing outstanding freeze-drying protective effect on biological system. The hydrogen bonding properties were studied in present work. The radial distribution functions g(r) and angle distribution around trehalose oxygen were calculated and the geometric criteria of trehalose involved H-bonds was confirmed. Then the constitutions and lifetimes of H-bonds in trehalose aqueous solutions with different concentration were obtained to study the dependence of hydrogen bonding properties on concentration. In fact, the formation of H-bonds between trehalose and water and between trehalose molecules is the essence of the protective effect. First, the addition of trehalose restrains the water molecules from rearrangement as a result of H-bonds network in the solution, thus reduces the probability of freezing. Second, the lifetimes of H-bonds involving trehalose (W-S/S-W and S-S H-bonds) were longer than the ones formed between water molecules(W-W H-bonds), meaning that the new H-bonds network established in the solution was stronger than in pure water. Moreover, the lifetimes of W-W H-bonds didn't increase significantly as the concentration increase. Thus it could be concluded that trehalose influence the dynamic property of the solution via enriching W-S/S-W and S-S hydrogen bonds rather than strengthening the W-W H-bonds. It was also found that trehalose realized protective action better at higher concentration as far as this study is concerned. Our finding provides beneficial help for the design and development of cryoprotectant.