Dynamics of glass-forming bioprotectant systems

In this work the dynamics of glass-forming mixtures showing a bioprotective function towards organisms under stress conditions is investigated. The behaviour of mixtures of two known glass-forming systems, such as α-d-glucopyranosyl α-d-glucopyranoside (trehalose) and 1,2,3-propanetriol (glycerol), are studied as a function of temperature and concentration. Both the fast local dynamics and the diffusive dynamics are determined by Inelastic Neutron Scattering and Quasi Elastic Neutron Scattering, respectively; more specifically the Boson peak behaviour, the mean square displacements and the translational linewidth as a function of temperature, wave-vector Q and concentration are characterized. The findings highlight an anomalous dynamic behaviour when a small amount of the alcohol is added to the disaccharide. This feature could be relevant in understanding the bioprotection mechanisms.