Harnessing Interfacial Phenomena to Program the Release Properties of Hollow Microcapsules

Abstract

The generation of near‐infrared (NIR)‐sensitive microcapsules is presented and it is demonstrated that the release properties of these microcapsules can be tailored by controlling their morphology. A biocompatible polymer, poly(DL‐lactic‐co‐glycolic)acid (PLGA) is used to form hollow microcapsules from monodisperse water‐in‐oil‐in‐water (W/O/W) double emulsions. Both the composition of PLGA and the oil phase of W/O/W double emulsions significantly affect the morphology of the subsequently formed microcapsules. PLGA microcapsules with vastly different morphologies, from spherical to “snowman‐like” capsules, are obtained due to changes in the solvent quality of the oil phase during solvent removal. The adhesiveness of the PLGA‐laden interface plays a critical role in the formation of snowman‐like microcapsules. NIR‐sensitive PLGA microcapsules are designed to have responsive properties by incorporating Au nanorods into the microcapsule shell, which enables the triggered release of encapsulated materials. The effect of capsule morphology on the NIR responsiveness and release properties of PLGA microcapsules is demonstrated.

One-Step Generation of Multifunctional Polyelectrolyte Microcapsules via Nanoscale Interfacial Complexation in Emulsion (NICE)

“…Analogous behaviors of inner core protrusion from W/O/W double emulsions have been observed when diblock copolymers, random copolymers and phospholipids were dissolved in the middle phase of W/O/W double emulsions. [43][44][45][46] However, a complete separation of the inner core from the oil phase has been seldom observed. 44,47 The interfacial complexation of bPEI and PAA leads to the ionization of functional groups of the two polymers, rendering the complex layer hydrophilic and more importantly oleophobic.…”

1. Photosensitive microcapsules

“…West and co-workers [22] suggested that the permeability changes of the N-isopropylacrylamide/acrylamide capsules walls containing gold nanoparticles, upon laser irradiation, could be useful in insulin therapy. Recently, Lee et al [23] prepared microcapsules of poly(DL-lactic-co-glycolic acid) (PLGA) containing gold nanorods by using water-oil-water (W/O/W) double emulsions. Upon laser irradiation, the nanorods generated heat via a photothermal effect, and as a result, the membrane became more permeable above the glass transition temperature of the PLGA, thereby providing remote control release of the active material.…”

Encapsulation of human serum albumin in submicrometer magnetic poly(lactide-co-glycolide) particles as a model system for targeted drug delivery

“…[19]). Double emulsion combined with a solvent evaporation technique was often used for preparation of microspheres both in batch (Rosca et al [20]) and microfluidic arrangement (Lee et al [21]). Preparation of nanoparticles was also investigated but resulting particles typically had irregular shape (Fonte et al [22], Zambaux et al [23]).…”