(175i) Stable Core-Shell Particles Produced By All-Aqueous Microfluidics

So far, the field of droplet microfluidics has relied on the use of organic solvents in combination with aqueous solutions to encapsulate materials and synthesize compartmentalized micro particles. A disadvantage of the use of organic solutions is that they harm biomaterial upon encapsulation.The obvious solution is to omit the use of organic solvents and produce compartmentalized micro particles from two or more immiscible aqueous solutions. Our group recently demonstrated the controlled and reliable formation of single and double emulsions from aqueous two phase systems (ATPS) [1-2]. Stabilization of these "water-in-water" and "water-in-water-in-water" droplets has turned out to be a challenge. 

In this contribution, we teach how to stabilize these all-aqeuous compartmentalized micro droplets and report permeable microparticles composed of a hydrogel shell and a liquid core. Drying and rehydration experiments demonstrate the permeability of the shell, which enables the molecular-weight-dependent release and uptake of polar solutes.