Design and fabrication of zwitter-wettable nanostructured films.

Manipulating surface properties using chemistry and roughness has led to the development of advanced multifunctional surfaces. Here, in a nanostructured polymer film consisting of a hydrophilic reservoir of chitosan/carboxymethyl cellulose capped with various hydrophobic layers, we demonstrate the role of a third design factor, water permeation rate. We use this additional design criterion to produce antifogging coatings that readily absorb water vapor while simultaneously exhibiting hydrophobic character to liquid water.

Recombinant protein-stabilized monodisperse microbubbles with tunable size using a valve-based microfluidic device.

Microbubbles are used as contrast enhancing agents in ultrasound sonography and more recently have shown great potential as theranostic agents that enable both diagnostics and therapy. Conventional production methods lead to highly polydisperse microbubbles, which compromise the effectiveness of ultrasound imaging and therapy. Stabilizing microbubbles with surfactant molecules that can impart functionality and properties that are desirable for specific applications would enhance the utility of microbubbles.

Drop-based microfluidic devices for encapsulation of single cells.

We use microfluidic devices to encapsulate, incubate, and manipulate individual cells in picoliter aqueous drops in a carrier fluid at rates of up to several hundred Hz. We use a modular approach with individual devices for each function, thereby significantly increasing the robustness of our system and making it highly flexible and adaptable to a variety of cell-based assays. The small volumes of the drops enables the concentrations of secreted molecules to rapidly attain detectable levels.