Dielectric Studies on Molecular Dynamics of Two Important Disaccharides: Sucrose and Trehalose

Abstract

Broadband dielectric measurements were carried out in the supercooled as well as in the glassy state of two very important disaccharides: trehalose and sucrose. Multiple relaxation processes were observed. Above the glass transition temperatures of examined disaccharides structural relaxation of cooperative origin was detected, where in the glassy state more local motions (secondary modes) appeared. Our data were discussed in light of the findings reported by other groups. We pointed out that sample preparation might impact mobility and, thus, dielectric loss spectra in a significant way. Consequently, it may lead to misinterpretation of the dielectric relaxation processes. Moreover, impact of physical aging and pressure on dynamics of two secondary relaxation processes observed in the glassy state of trehalose and sucrose has been investigated. Additionally, we have demonstrated that, in contrast to the calorimetric measurements (DSC), activation energies of the β- and γ-relaxation processes observed in the glassy state of sucrose and trehalose do not change as a result of physical aging. Finally, we found out that the β-relaxation process slows down as pressure increases. We interpreted this fact in view of increasing rigidity of the structures of disaccharides.

Trehalose or Sucrose: Which of the Two Should be Used for Stabilizing Proteins in the Solid State? A Dilemma Investigated by In Situ Micro-Raman and Dielectric Relaxation Spectroscopies During and After Freeze-Drying

“…(2) The spectrum shown for FD trehalose is representative (at least qualitatively) of the dynamics of both disaccharides in the glassy state (see Supporting Information). The most intense and well-resolved peak has asymmetric shape (HN function with a HN ¼ 0.37; b HN ¼ 0.65) and is identified with the secondary g-relaxation observed by Kaminski et al 56 This process has been related to motions of exocyclic hydroxymethyl groups. 56 The slower process, identified with the secondary b-relaxation by Kamniski et al, 60 is symmetrically broadened (CC function with a HN ¼ 0.44; b HN ¼ 1) and…”

“…Molecular dynamics of lysozyme, trehalose, and sucrose are the subject of interest for many researchers. [47][48][49][50][51][52][53][54][55][56][57][58][59] It is difficult, however, to understand the relationship between the dynamics of vitreous matrices and the bioprotective effect by analyzing only pure compounds, independently. To tackle this challenge, we focused our study on the dielectric characterization of FD complex formulations Lys þ Treh and Lys þ Sucr, to characterize the molecular dynamics of the vitreous matrix below T g .…”

“…61 On account of the sensibility of this process regarding some experimental parameters such as pressure and water content, it was also identified as a Johari-Goldstein b-relaxation that is intermolecular in nature. 56 (3) It is noticeable that the corresponding peaks of g-process in FD trehalose and II-process of FD lysozyme are located nearly at the same position and are characterized by identical temperature dependence of the corresponding relaxations times (i.e., identical activation energy, see Table 1). Keeping in mind these considerations, the first dielectric results obtained for FD Lys þ Treh and FD Lys þ Sucr in the present work can be described, from high to low frequencies, as follows.…”

Does Urea Alter the Collective Hydrogen‐Bond Dynamics in Water? A Dielectric Relaxation Study in the Terahertz‐Frequency Region

“…[34] A broadband dielectric spectroscopic study by Kaminski et al concluded that aqueous sucrose solutions exhibit three different relaxation modes in the low-frequency region, namely, the a ( % 10 À6 s), g ( % 10 À7 s), and b ( % 10 À9 s) relaxation mode. [35] A double-Debye (and/or Cole-Cole) relaxation fitting of dielectric measurements in the 200 MHz-40 GHz region by Fuchs et al [34a] and Weingärtner et al [34b] have extracted two gross relaxation times, which are on the order of approximately 10 ps and approximately 35-45 ps for a 1 m sucrose solution, the former being the rotation of water, whereas the second one is subdiffusive in nature. The focus of our present investigation is the change in the ultrafast collective hydrogen-bond dynamics, which extend up to several hydration layers and leaves its imprint in the terahertz-frequency region only.…”

Protein Quantity on the Air–Solid Interface Determines Degradation Rates of Human Growth Hormone in Lyophilized Samples

“…One possible explanation to this conundrum is that during storage, protein molecules in glassy solids might accumulate small conformational changes that prime them to become increasingly aggregation‐competent upon reconstitution . However, no evidence showing the accumulation of this type of aggregate‐competent species during storage has been presented, perhaps in part because of the relatively low sensitivity of available optical spectroscopies to examine protein structure in dry solids . Aggregation of proteins after lyophilization and reconstitution is often correlated with the extent of loss of native protein structure that occurs during the lyophilization process, with those formulations and conditions that yield the greatest loss of native structure resulting in the most aggregation upon reconstitution .…”