Inelastic neutron scattering study on bioprotectant systems.

We collected inelastic neutron scattering (INS) spectra of homologous disaccharide (C12H22O11)/H2O mixtures at a very low temperature by using indirect geometry time-of-flight spectrometer TOSCA at the ISIS pulse neutron facility (DRAL, UK). The aim of this work is to investigate the vibrational behaviour of trehalose, maltose and sucrose/H2O mixtures with INS in order to characterize the structural changes induced by these disaccharides on the H2O hydrogen-bonded network. A higher degree of 'crystallinity' for the trehalose/H2O system is observed in the vibrational region corresponding to the ice bending modes. This feature could justify the better cryptobiotic action of trehalose compared with maltose and sucrose. On the other hand, the better bioprotective effectiveness could be explained by the higher destructuring effect of trehalose, emphasized by the analysis of the librational modes region.