“The broader field of microfluidics encompasses a wide variety of different research topics ranging from basic fluid mechanics problems to protein crystallization and drug discovery.”

Double emulsions consist of one or more small droplets suspended within a larger drop of a second immiscible liquid, which is itself suspended within a third immiscible liquid. Two different types of double emulsions can be generated: water-in-oil-in-water (w/o/w) and the inverse, oil-in-water-in-oil (o/w/o). Because they contain both "oil" and water phases, double emulsions are useful for encapsulating both hydrophobic and hydrophilic substances simultaneously. They are typically made with a two-step process where two immiscible liquids are sheared together with a surfactant, generating an emulsion. This emulsion is then blended into a third liquid with an additional surfactant. This process introduces polydispersity at each set. In addition, this technique provides no control over the number of encapsulated inner droplets.

I believe that our contribution in this area lies in the fact that we were able to demonstrate a robust method for generating truly monodisperse double emulsion drops that contain a single inner droplet. Moreover, we generate these monodisperse double emulsions in a capillary microfluidic device with a very simple geometry. The ability to generate such nearly perfect core-shell structures then provides a platform from which to fabricate novel spherically layered materials. We have generated a variety of different core-shell structures with materials such as diblock copolymers, phospholipids, colloidal suspensions, photo-initiated polymers, liquid crystals, and microgels. I believe that our paper has been cited frequently because of the potential that it demonstrates in creating new materials with microfluidics.

Dr. Andrew S. Utada's most-cited paper which is also represented in the Research Front map with 65 cites to date: Utada, AS, et al., "Monodisperse double emulsions generated from a microcapillary device," Science, 308 (5721): 537-541, APR 2005. Source: Essential Science Indicators.

I became involved in this research as a graduate student in David Weitz’s group at Harvard University. I joined the group at a time when he and a few post-doctoral fellows began working on controlling drop breakup in microfluidic channels. We have also had collaboration with the groups of Howard Stone and George Whitesides, who also have also been doing microfluidics research at Harvard.

The biggest success for us, I believe, was using the monodisperse double emulsions as templates to form new materials.

I plan to continue doing research on the interface between basic and applied sciences. I feel that both are equally important.

The broader field of microfluidics encompasses a wide variety of different research topics ranging from basic fluid mechanics problems to protein crystallization and drug discovery. In addition, there appears to be a strong effort to develop microfluidic chips capable of manipulating and analyzing tiny quantities of precious liquids. I see this huge diversity further expanding as more researchers begin to utilize this tool.

Our work demonstrates methods for creating monodisperse capsules of variable sizes. This work could find practical application in the fabrication of small quantities of designer core-shell structures to protect a precious deliverable or in the formation of layered particles that have different properties in each layer.