Aqueous two-phase systems (ATPS) are formed when two incompatible polymers, such as polyethylene glycol (PEG) and dextran (DEX), are mixed in water and phase-separated above a critical polymer concentration. The all-biocompatible nature of ATPS makes them promising for cell transplant immunoisolation applications by coating and encapsulation. 

This talk describes implementations of ATPS in microfluidic systems. In the first system, microparticles and cells are controllably self-assembled at an ATPS two-phase interface, and pulled across the interface by a magnetic force, to coat the assembly. The second system uses microfluidics to generate water-in-water microemulsions with a high degree of monodispersity, by both active perturbation and completely passive flow focusing methods, demonstrating utility in controlled encapsulation and release of microparticles and cells. Finally, simple mathematical models are developed to understand each fluidic process, and predict the size of the self-assembled cell clusters and the size of the generated water-in-water emulsions.

机械系陈皓生老师邀请，联系方式：chenhs@tsinghua.edu.cn