Accumulation and Desorption of Biomolecules at Liquid-Liquid Interfaces in Aqueous Two-Phase Systems

长链DNA分子或蛋白质在两相体系中会在相界面处聚集成凝胶状。通过随后的电场强度的增加，将引发分子到相邻相中的解吸。在拟议的项目中，应该研究不同的蛋白质种类或长链DNA分子可以在多大程度上被分离。为此，将设计和制造专用的微流体系统。DNA分子在相界处的拉伸将通过落射荧光显微镜来表征。将研究实现不同分子分离的不同方法。在一种特殊的配置中，液体层由伸展的DNA分子桥接。薄片宽度将被选择为使得理想地仅较大的分子可以渗透到相邻相中。此外，将对蛋白质进行类似的实验，其目标是根据其质量或等电点等特定性质实现分离。首先，拟议的项目应有助于证明新的机制，分离和纯化的生物分子混合物。除此之外，实验将产生数据，可以导致更好地理解在水两相系统中的相边界的形态。

Long-chain DNA molecules or proteins will be accumulated electrophoretically at the phase boundary in an aqueous two-phase system. Via the subsequent increase of the electric field strength, the desorption of the molecules into the adjacent phase will be initiated. In the proposed project it should be studied in how far different protein species or long-chain DNA molecules can be separated that way. For that purpose a dedicated microfluidic system will be designed and fabricated. The stretching of DNA molecules at the phase boundary will be characterized by epifluorescence microscopy. Different methods for achieving a separation of dissimilar molecules will be studied. In a special configuration a liquid lamella is bridged by the stretched DNA-molecules. The lamella width will be chosen such that ideally only the larger molecules can penetrate into the neighboring phase. Moreover, similar experiments will be performed with proteins, where the goal is to achieve a separation according to specific properties such as their mass or isoelectric point. In the first place, the proposed project should serve to demonstrate novel mechanisms for the separation and purification of biomolecular mixtures. Besides that, the experiments will produce data that could lead to a better understanding of the morphology of the phase boundary in aqueous two-phase systems.