High order emulsionsDavid A. Weitz, Harvard University, DMR 0602684

Core-shell structures are useful for the encapsulation and triggered release of precious materials, such as cosmetics, nutrients, and targeted drugs.

We have developed a simple method to form core-shell structures from multiple emulsions. The structures can be formed with superb control over their morphology and size. This allows us to create higher order emulsions that are impossible to create otherwise.

As an example, we show a quintuple emulsion, consisting of a core water drop, inside an oil drop, inside a water drop, inside an oil drop, inside a water drop, dispersed in oil. Such structures cannot be made by any other means.

Microfluidic fabrication of monodisperse biocompatible and biodegradable polymersomes with controlled permeability

David A. Weitz, Harvard University, DMR 0602684

Polymersomes consist of diblock copolymers assembled into a vesicle structure. They are useful for the encapsulation, transport, and targeted release of actives.

We have developed a simple and versatile technique for fabricating polymersomes that are completely biocompatible and biodegradable and that encapsulate the actives with 100% efficiency. When triggered by an osmotic shock, the polymersomes release their cargo, providing a simple and effective release mechanism.

The polymersomes are fabricated from double emulsion templates produced in a microfluidic device. The diblock copolymers are dissolved in a volatile solvent that is evaporated to form the polymersomes. This affords superior control over polymersome size and provides high encapsulation efficiency.

Dewetting

Solvent Evaporation

Triggered Release

Diblock copolymer

solvent

SolventRemoval

Double Emulsion Drop Vesicle

Industrial applications of glass-capillary microfluidics

David A. Weitz, Harvard University, DMR 0602684

Microcapsules have potential uses in the pharmaceutical, cosmetic, food, and biotechnology industries. With glass capillary microfluidics, we design and produce monodisperse microcapsules with diameters ranging from a few microns to a few millimeters.

These devices have great potential for commercialization to create new structures that can be used in many applications, from cosmetics to food. A new company is being formed to explore these applications. This company will provide new high-tech employment opportunities for scientists and engineers.

Top: capillary device producing monodisperse emulsions. The inner drop is 50 µm in diameter. Middle: biodegradable microcapsules for cosmetic applications. Image on the right shows the encapsulating efficiency. Bottom: synthetic caviar produced with our technology. The capsules contain pistachio flavored olive oil.

50 µm

2 mm