Below are our current areas of research.
Colloids are microscopic particles so small that they move diffusively when dispersed in a fluid, exhibiting Brownian motion, controlled by the temperature of the system, like atoms. However, unlike atoms, colloids are big enough to see with light, so they can be probed with microscopes and laser light scattering. The interactions between atoms are fixed, dictated by quantum mechanics, but those in colloids can be very finely tuned.
The group studies a variety of biological systems from a soft matter perpsective. A biological cell is a material with complex properties arising from a composite and highly dynamic, non-equilibrium intracellular biopolymer network — the cytoskeleton. The material properties of cells determine how they sense and respond to the outside world. Other topics of investigation include C. elegans worms and bacterial biofilms.
We develop microfluidic systems to investigate the fundamentals of two-phase flow in porous media. These three-dimensional (3D) model systems allow us to fully visualize the multiphase flow, in 3D, at pore-scale resolution, using confocal microscopy. Moreover, we instrument these systems to simultaneously image the flow and probe their bulk transport properties. We also develop new materials that control the flow in the porous material. This work is motivated by the need to direct fluids for improved resource recovery.
We primarily study three aspects of microfluidics: the physics of microfluidics, the engineering of microfluidic devices, and the application of microfluidics to biology and materials science.
We examine phenomena such as clogging and drop formation, and develop models for the physical mechanisms and principles behind these behaviors. This helps us better understand how fluids and particles flow at low Reynolds numbers in micron-scale channels.
Secondly, we develop new ways to create, control, and manipulate microfluidic droplets. These include ways to add and remove reagents or particles from drops, label drops using optical or other barcodes, scale up drop production for industrial applications, and create multiple emulsions of different species. We engineer silicone (PDMS) and glass microcapillary devices to perform these manipulations.
Finally, we apply microfluidic drops and devices to questions in biology and materials science. We use drops and channels as picoliter-sized biological reactors for single-template PCR, library screening, and cell culture. We also use drops to encapsulate actives such as pharmaceuticals for targeted drug delivery with smart materials, or air as an acoustic contrast agent for seismic imaging of oil reservoirs.