Le Mans Université , IMMM UMR-CNRS 6283, Polymères, Colloïdes et Interfaces , 72085 Le Mans Cedex 9 , France.
J Phys Chem B. 2018 Aug 23;122(33):8075-8081. doi: 10.1021/acs.jpcb.8b04963. Epub 2018 Aug 14.
Transport properties of macromolecules in dense aggregate suspensions and gels of proteins are important for usage of these biomaterials in areas such as pharmaceutics, food, and cosmetics. The mobility of polymers in protein gels has received some attention in the past, but the mobility in dense aggregate suspensions has not yet been investigated. In this study, self-diffusion of probe dextran chains was studied in suspensions of aggregates with different size and morphology and in gels using fluorescence recovery after photobleaching over a wide range of concentrations. Brownian diffusion of the probes was observed in aggregate suspensions as well as in weak gels formed just beyond the critical gel concentration. Diffusion of polymers in dense suspensions of protein aggregates depends not only on the concentration but also on the size and morphology of the aggregates. It is not directly related to the viscosity or the dynamic correlation length. Diffusion of polymers in protein gels is anomalous and occurs on logarithmic time scales. The recovery of the fluorescence for densely cross-linked gels was logarithmic with time, suggesting an exponential distribution of diffusion coefficients.
在药剂学、食品和化妆品等领域，大分子在密集聚集物悬浮液和蛋白质凝胶中的传输性质对于这些生物材料的使用非常重要。过去，人们已经关注了聚合物在蛋白质凝胶中的迁移性，但在密集聚集物悬浮液中的迁移性尚未得到研究。在这项研究中，使用光漂白后荧光恢复技术，在广泛的浓度范围内研究了不同大小和形态的聚集物悬浮液以及凝胶中探针葡聚糖链的自扩散。在聚集物悬浮液以及刚超过临界凝胶浓度形成的弱凝胶中观察到了探针的布朗扩散。在密集的蛋白质聚集物悬浮液中聚合物的扩散不仅取决于浓度，还取决于聚集物的大小和形态。它与粘度或动态相关长度没有直接关系。聚合物在蛋白质凝胶中的扩散是异常的，并且在对数时间尺度上发生。密集交联凝胶的荧光恢复随时间呈对数关系，这表明扩散系数呈指数分布。
