Temperature scanning FTIR analysis of interactions between sugar and polymer additive in amorphous sugar–polymer mixtures

Temperature scanning FTIR analysis of secondary structures of proteins embedded in amorphous sugar matrix

“…Such a transformation from static hydrogen bonds to nonstatic ones due to increasing temperature above the T g would lower the net degree of sugarprotein hydrogen bonding, which corresponds to the disruption of hydrogen bonding, as indicated by the positive shift of the IR band due to O-H stretching vibration. 12,13,23 In contrast to the trehalose-and maltose-BSA samples, the dextran-BSA sample does not exhibit an abrupt increase in the slope of a-helix loss near T g (Fig. 5).…”

“…12,13,23 Similarly, the loss of sugar-protein hydrogen bonds in an amorphous sugar solid is expected to occur in a much wider temperature range than does the thermal denaturation of protein in an aqueous solution. Consequently, the heat-induced conformational change of protein embedded in an amorphous sugar matrix may occur in a much wider temperature range than that for an aqueous protein solution, as shown in Figure 2e.…”

“…12,13 In brief, a BaF 2 disc, with a dehydrated sugar-protein mixture, was placed in a SpectraTech Heated Cell (Shelton, CT) and then heated at a rate of 1.08C/min from room temperature (25 AE 58C) to more than 1508C. The sample temperature was monitored and controlled using an ES100P digital controller (OMRON Co., Kyoto, Japan) that had been calibrated using a previously prepared calibration plot.…”

“…12,13,23 Namely, peak positions of the IR band due to O-H stretching vibration of sugar-protein mixtures were read from the IR spectra obtained at different temperatures and plotted against the corresponding temperatures. It has been well documented that the IR peak position increases linearly with increasing temperature, and at approximately the T g value, the slope of the increase in the peak position abruptly becomes larger.…”

Water Sorption Glass Transition Protein-Stabilizing Behavior of an Amorphous Sucrose Matrix Combined With Various Materials

“…5,6,10 Polysaccharides and polymers have been reported to increase the T g values of amorphous oligosaccharides. [11][12][13][14] On the other hand, it has recently been reported that the addition of phosphate salts to an amorphous sugar matrix can also increase the T g value. [15][16][17][18] This suggests that highly polarized substances and substances that contain polar groups could also be used to improve the physical stability of an amorphous sugar matrix.…”