Compartmentalized Polyampholyte Microgels by Depletion Flocculation and Coacervation of Nanogels in Emulsion Droplets.

In pH‐responsive drug carriers, the distribution of charges has been proven to affect delivery efficiency but is difficult to control and verify. Herein, we fabricate polyampholyte nanogel‐in‐microgel colloids (NiM−C) and show that the arrangement of the nanogels (NG) can easily be manipulated by adapting synthesis conditions. Positively and negatively charged pH‐responsive NG are synthesized by precipitation polymerization and labelled with different fluorescent dyes. The obtained NG are integrated into microgel (MG) networks by subsequent inverse emulsion polymerization in droplet‐based microfluidics. By confocal laser scanning microscopy (CLSM), we verify that depending on NG concentration, pH value and ionic strength, NiM−C with different NG arrangements are obtained, including Janus‐like phase‐separation of NG, statistical distribution of NG, and core–shell arrangements. Our approach is a major step towards uptake and release of oppositely charged (drug) molecules. [ABSTRACT FROM AUTHOR]