Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden.
J Phys Chem B. 2013 Feb 28;117(8):2554-63. doi: 10.1021/jp311968b. Epub 2013 Feb 12.
Hydration of films of pig gastric mucin was studied using a quartz crystal microbalance with dissipation monitoring (QCM-D) equipped with a humidity module. As a prerequisite, the water adsorption isotherm of a clean silica surface was determined. Atomic force microscopy was used to characterize the changes occurring on the silica surface after repeated sorption/desorption and cleaning cycles. The water sorption isotherms of several hundreds of nanometers thick mucin films were obtained in QCM-D experiments using analysis of overtone behavior. The results show that the sorption isotherms are not dependent on the film thicknesses and are in good agreement with sorption calorimetric data on mucin in the bulk phase. Moreover, hydration-induced changes of rheological properties of mucin films were investigated using a model-free approach. The ratio of G'/G″ was evaluated as a function of relative humidity. The transition from solidlike behavior to liquidlike behavior was observed in the same humidity range as in sorption calorimetric experiments. Thus, ability of QCM-D to monitor glass transition in biopolymers was demonstrated.
使用配备湿度模块的石英晶体微天平（QCM-D）研究了猪胃粘蛋白膜的水合作用。作为前提条件，确定了清洁二氧化硅表面的水吸附等温线。原子力显微镜用于表征在反复吸附/解吸和清洁循环后发生在二氧化硅表面上的变化。在 QCM-D 实验中，通过分析泛音行为获得了数百纳米厚的粘蛋白膜的水吸附等温线。结果表明，吸附等温线不依赖于膜厚度，并且与在本体相中粘蛋白的吸附量热数据吻合良好。此外，使用无模型方法研究了粘蛋白膜流变性质的水合诱导变化。作为相对湿度的函数评估了 G'/G″的比值。在与吸附量热实验相同的湿度范围内观察到从固态到液态的转变。因此，证明了 QCM-D 监测生物聚合物玻璃化转变的能力。
