Double‐Emulsion‐Templated Anisotropic Microcapsules for pH‐Triggered Release

E-ISSN： 2196-7350|5|4|admi.201701472-admi.201701472

ISSN： 2196-7350

Source： ADVANCED MATERIALS INTERFACES (ELECTRONIC), Vol.5, Iss.4, 2018-02, pp. : n/a-n/a

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Abstract

AbstractBiocompatible microcapsules with a function of pH‐triggered release are promising for the site‐specific release of bio‐actives in the human body. In this work, smart microcapsules with three distinct configurations of membranes are produced to control the rate of pH‐triggered release. The microcapsules are prepared with a template of water‐in‐oil‐in‐water double‐emulsion drops. The oil shells of drops contain two polymers dissolved in an organic solvent: one is a biodegradable polymer selected from poly(lactic acid), poly(lactic‐co‐glycolic acid), and polycaprolactone, and the other is a pH‐responsive cationic polymer. Upon the depletion of organic solvent, two polymers confined in the shell undergo phase separation and double‐emulsion drops transform to microcapsules with the solid membrane. Three different configurations of the membranes − spherical, snowman‐like, and eyeball‐like structures − are exclusively produced according to the selection of biodegradable polymers. Although all the microcapsules release hydrophilic encapsulant loaded in the core when they are subjected to a weakly acidic condition, the release kinetics strongly depends on the configuration of the membrane. Larger surface coverage and thinner membrane of pH‐responsive domains result in faster release.