Study of longitudinal dynamics of trehalose–water solutions by inelastic ultraviolet scattering

Abstract

Among disaccharides, trehalose is demonstrated to be the most efficient bioprotecting agent against dehydration and freezing and it has been identified, at high concentration, in several natural organisms with important applications in the preservation of mammalian cells. However, despite its relevance in biopreservation, the physical mechanism underlying the effectiveness of trehalose has not yet been definitely clarified. One reason could rely on the experimental difficulty in measuring the dynamics of the trehalose–water system at high concentration, as its behaviour is often derived as an extrapolation from low-concentration data. In this report we present the results of a feasibility experiment in which the dynamic structure factor S(Q, ω) of a trehalose–water solution at high trehalose concentration (79% w) has been measured for the first time over a rather large temperature range (235 K < T < 343 K) by means of inelastic ultraviolet scattering at a momentum transfer of Q ≈ 0.1 nm⁻¹. We observe a pronounced increase in the mode frequency upon cooling and a non-monotonic variation of the mode frequency width with a maximum at T ≈ 330 K, typical features of the structural relaxation of liquids approaching a glass transition.