Jacinta C. Conrad

Principal Investigator University of Houston

Jaci Conrad is fascinated by soft materials, such as inks, paints and coatings, which readily deform and exhibit unusual mechanics that are somewhere between those of solids and liquids. Her interests span surfaces and complex fluids, microbiology near interfaces, colloids in confinement and in flow, nanoparticles in transport and diagnostics for public health. She has found that the physics are often similar across systems.

With small particles, such as colloids, nanoparticles, bacteria, viruses and proteins, Dr. Conrad explores how they assemble and transport in fluids and near surfaces that confine, crowd or support them. For example, she wants to understand how particles are transported into and move through very crowded fluids, which serve as models for cells. Insights gained here could help improve drug delivery and the understanding of other biological processes.

In other collaborative work, her team is using microfabrication and microscopy to investigate how bacteria move on, interact with and adhere to interfaces, and how to modify bacterial motility. This research could have applications for medical diagnostics, antifouling materials and bioremediation.

Her team also is using microfluidics and particle-tracking to develop assays to detect proteins, viruses and bacteria with the goal of creating ultrasensitive diagnostics for bioterrorism and public health.

The Welch grant supports her work with glassy materials made of small particles, a difficult problem that has been intensely studied for decades.

“Because it has been such an outstanding challenge in fundamental science, it would be next to impossible to get funding if not for Welch,” Dr. Conrad said. “Glasses look like liquids structurally but behave mechanically like a solid. They relax cooperatively, depending on the interactions between particles. Understanding how this happens at the single-particle level will be illuminating for other glassy systems.”

Dr. Conrad uses an analogy to illustrate the collective relaxation of dense particulate materials. In a traffic jam, she says, you can’t move until the car in front of you does and then all the cars start to move together.

Welch support is “amazing,” she said. “It allows us to do good science in one system and then, by looking for connections, it allows us to do good science in other areas as well.”

Dr. Conrad jokes that her decision to pursue soft matter physics was spurred by toothpaste. She still vividly remembers her PhD advisor at Harvard discussing its unusual mechanics: When you squeeze the tube, it flows like a liquid, and then sits on your toothbrush like a solid.

“Welch has allowed me to build a body of very fundamental work and explore questions in ways we wouldn’t otherwise be able to,” she added. “I am so thankful.”