Microfluidically produced microcapsules with amphiphilic polymer conetwork shells

Microcapsules with an aqueous core can be conveniently prepared by water-in-oil-in-water double emulsion microfluidics. However, conventional shell materials are based on hydrophobic polymers or colloidal particles. Thus, these microcapsules feature a hydrophobic shell impermeable to water-soluble compounds. Capsules with semipermeable hydrogel shells have been demonstrated but may exhibit poor mechanical properties. Here, amphiphilic polymer conetworks (APCNs) based on poly(2-hydroxyethyl acrylate)-linked by-polydimethylsiloxane (PHEA-l-PDMS) are introduced as a new class of wall materials in double emulsion microcapsules. These APCNs are mechanically robust silicone hydrogels that are swellable and permeable to water and are soft and elastic when dry or swollen. Therefore, the microcapsules can be dried and rehydrated multiple times or shrunken in sodium chloride salt solutions without getting damaged. Moreover, the APCNs are permeable for hydrophilic organic compounds and impermeable for macromolecules. Thus, they can be loaded with macromolecules or nanoparticles during microfluidic formation and with organic molecules after capsule synthesis. The microcapsules serve as microreactors for catalytically active platinum nanoparticles that decompose hydrogen peroxide. Finally, the surface of the APCN microcapsules can be selectively functionalized with a cholesterol-based linker. Concluding, APCN microcapsules could find applications for the controlled delivery of drugs, as microreactors for synthesis, or as scaffolds for synthetic cells.