Controlling the Morphology of Hollow Microcapsules From Double Emulsions

Double emulsions are used as templates to generate hollow microcapsules with controlled morphology.  A biocompatible polymer, poly(DL-lactic-co-glycolic)acid (PLGA), is used to form hollow microcapsules. Monodisperse water-in-oil-in-water (W/O/W) double emulsions are generated using a microfluidic device.  The middle oil phase of W/O/W double emulsions comprises a mixture of volatile organic solvents and PLGA. By removing the solvents from W/O/W double emulsions, PLGA hollow microcapsules are generated. We study the effect of the composition of PLGA and that of the oil phase of W/O/W/ double emulsions on the morphology of PLGA microcapsules.  PLGA microcapsules with vastly different morphologies are obtained due to the change in the solvent quality of the oil phase and the formation of adhesive oil-water interfaces during solvent removal.  We also show that it is possible to generate near-infrared (NIR) light sensitive microcapsules by incorporating gold nanorods into PLGA microcapsule shell.  The effect of the capsule morphology on the NIR sensitivity of PLGA microcapsules will be discussed.