α,α-Trehalose/Water Solutions. 5. Hydration and Viscosity in Dilute and Semidilute Disaccharide Solutions

Abstract

We report viscosity and compressibility measurements of trehalose, maltose, and sucrose aqueous solutions at different concentration and temperature values. What emerges from the concentration dependence of viscosity and compressibility is that trehalose, in comparison to maltose and sucrose, shows a higher interaction strength with water, which gives rise to a greater value of the hydration number throughout the investigated temperature range. Furthermore, viscosity measurements reveal that at high concentration values, trehalose shows a "stronger" kinetic character than the other disaccharides, namely, a lower structural sensitivity to temperature changes in the investigated temperature range. This result could explain the greater cryptobiotic attitude of trehalose at high concentrations. The present work, which consists of quantifying experimentally the basic hydration behavior and solution structure of the investigated disaccharides as a function of concentration and temperature, allows the working hypothesis of the several existing simulation approaches to be tested.

Freezing Properties of Disaccharide Solutions: Inhibition of Hexagonal Ice Crystal Growth and Formation of Cubic Ice

“…Then the water molecules constructing the ice Ic would slightly interact with disaccharide molecules even though they are not bound to the disaccharide molecules directly. The transition temperature from ice Ic to ice Ih was around 240 K which coincides well with the vitrification temperature (T g ') of the disaccharide solution; T g ' was approximately 238 K, 234 K and 233 K for the 50 wt% concentration of the trehalose, sucrose and maltose solutions, respectively (Branca et al, 2001). This is also the case for T g '=230 K of glucose Thanatuksora et al, 2008) and for the eutectic point of 67 wt% glycerol at 230 K (Vigier et al, 1987;Berejnov et al, 2006).…”

“…In Figure 7, several reported viscosities measured using the conventional techniques are presented simultaneously. Most of the bulk viscosities of disaccharide solutions were measured by mechanical viscometers: the Ubbelohde viscometer (Magazù et al, 1999;Elieas & Elias, 1999;Branca et al, 2001), the Marion-Krieger Sisco capillary viscometer (Matsuoka et al, 2002), or the rotational viscometer (Nagasawa et al, 2003). The selected literature data plotted in Figure 7 were measured in a temperature range of 293.2-313.2 K. Viscosities of other disaccharide solutions, sucrose (η suc ) and maltose (η mal ), were found to be similar to that of η treha at a given concentration within the experimental uncertainties (shown in Figure 7).…”

“…Sample (b) was stored in a vacuum chamber and heated at a temperature of approximately 180 K. After approximately one hour the sample was fractured to form the replica. Sample (c) was heated to approximately 250 K, which is sufficiently higher than the vitrification temperature (T g ') of trehalose (approximately 238 K for 50 wt% trehalose solution; Branca et al, 2001). Figure 5 shows the comparison of the TEM images for these three samples taken at the same magnification.…”

Slowing down of water dynamics in disaccharide aqueous solutions

“…These differences emerge on D w only at 66 wt %, at which the numbers of waterwater and water-sugars HBs are comparable. Then, D w is found the lowest in the trehalose solution, as could be expected from its larger hydration number [18,26,27]. [41] for pure water and from Rampp et al [39] in 10, 30, 50 and 60 wt % trehalose solutions are also reported as a triangle and stars symbols, respectively.…”

“…Therefore, their bioprotective effect is thought to partially stem from the significant slowing down they induce on the dynamics of protein hydration water molecules [15,16,17]. Indeed, sugars form numerous hydrogen bonds (HBs) with water [18,19], whose dynamics is strongly slow down in their hydration shell [15,20,21,22]. Recently, disaccharides were shown to decrease the flexibility of lysozyme [17,23], thereby reducing its conformational entropy.…”