Fig. 5.

Strategies of on-chip extractions for hydrogel microcapsules from oil into aqueous phase. (A) Double emulsion with a sacrificial ultra-thin oil shell that can spontaneously dewet from hydrogel microcapsules. Image is reprinted and recreated with permission from reference 151. (B) Fluid exchange of carrier phase based on oil depletion and water infusion with multiple side branches. Image is reprinted and recreated with permission from reference 125. (C) Extraction chamber with mechanical filter gate to block the pass of microcapsules. Image is reprinted and recreated with permission from reference 116. (D) The criterion of stable oil-aqueous interface in microchannel for continuous extraction. (E) Interfacial tension (FIFT) based extraction of hydrogel microcapsules. Images (D–E) are reprinted and recreated with permission from reference 97. (F) Dielectrophoretic force (FDEP) based extraction for mechanical stiffness-independent microcapsules. Image is reprinted and recreated with permission from reference 152.