Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China.
Soft Matter. 2018 Feb 28;14(9):1552-1558. doi: 10.1039/c7sm02275a.
Partitioning refers to the distribution of solute molecules in the two immiscible phases of a mixture of two solutions, such as an aqueous two-phase system (ATPS). The partitioning of RNA and peptide has been adjusted in situ to facilitate their assembly into intracellular membraneless organelles. Despite the immense potential of this approach in artificial systems, a partitioning-dependent assembly of macromolecules has been limited, due to the sophisticated processing associated with their in situ modification. Here we demonstrate an approach to direct the assembly of polyelectrolytes in an ATPS through varying their partitioning via pH changes. Microcapsules can be converted to microgel particles as the polyelectrolytes selectively partition to different emulsion phases when changing pH. Such partitioning-dependence can also be equally applied for complexing hydrophilic nanoparticles with polyelectrolytes in an ATPS. By enabling access of hydrophilic materials across the aqueous interface freely, the ATPS allows modification of their intrinsic properties in situ; this advantage will inspire more versatile control over the partitioning of hydrophilic materials and will create new multi-functional biomaterials.
分配是指溶质分子在两种不可混溶溶液混合物的两相中的分布，例如双水相系统 (ATPS)。已经对 RNA 和肽进行了原位分配调整，以促进它们组装成无膜的细胞内细胞器。尽管这种方法在人工系统中有巨大的潜力，但由于与其原位修饰相关的复杂处理，大分子的分配依赖组装受到限制。在这里，我们通过改变 pH 值来改变其分配，展示了一种通过改变 pH 值来直接在 ATPS 中组装聚电解质的方法。当改变 pH 值时，微胶囊可以转化为微凝胶颗粒，因为聚电解质选择性地分配到不同的乳液相中。这种分配依赖性也可以同样应用于在 ATPS 中用聚电解质络合亲水性纳米颗粒。通过允许亲水性材料自由地穿过水相界面，ATPS 允许对其内在特性进行原位修饰；这一优势将激发对亲水性材料分配的更通用控制，并将创造新的多功能生物材料。
