Emulsion-templated liquid core-polymer shell microcapsule formation

Abstract

The fabrication of hollow microspheres to encapsulate functional molecules, such as drugs, insecticides, and proteins, is of ever-increasing importance. Many chemical and physicochemical methods have been tested for various specific encapsulations, but most of them have not been developed into an industrial process. In this work, we present a straightforward method to prepare liquid core-polymer shell microcapsules by first templating an oil-in-water emulsion stabilized by an interfacial monolayer of polystyrene latex particles (often referred to as "Pickering emulsion"), and subsequently locking the assembled particles into a robust polymeric shell through the precipitation of a biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) at the interface. The resultant microcapsules that have a solid polymeric enveloped around the oil droplets are stable and retain their integrity during the drying in air. Therefore, they should have great potential to serve as vehicles for encapsulating functional molecules especially hydrophobic in nature.