Christine Payne: Investigating Interactions between Cells and Engineered Materials

Christine Payne will join the faculty of Duke University’s Department of Mechanical Engineering & Materials Science beginning January 1, 2018. With research focused on understanding how biological cells interact with artificial materials, Payne’s work seeks to provide foundations for engineering new nanoparticles for medical applications as well as understanding how commercial nanoparticles in everyday products like sunscreen affect the body. She is also working to design flexible, electrically active polymers for biomedical applications.

Nanoparticles are already used for many medical purposes, such as treating cancer and providing contrast for imaging technologies. However, researchers’ understanding of how such nanoparticles interact with cells and proteins is extremely limited.

“When you put nanoparticles into the bloodstream, it quickly becomes a very complicated mixture,” said Payne, who joins Duke from the Georgia Institute of Technology, where she has been a faculty member since 2007. “You can design a nanoparticle to serve a certain function, but when it gets into the body, proteins will latch onto its surface and affect how it behaves with cells. And the nanoparticle will, in turn, deform the protein and affect how it behaves as well. It’s a complex three-body interaction, and it’s very difficult to control.”

Payne’s laboratory uses physical experiments to understand these questions. Students on her research team are often found designing and building microscopes for techniques such as fluorescence microscopy to view the interactions of different nanoparticles with cells as they unfold. They also work with other forms of spectroscopy to discover the impact of protein-nanoparticle interactions, such as changes in protein structure.

“I think it will be very good for my research to be surrounded by materials engineers. Duke also has a very strong chemistry department—I already know several of the faculty there—so it will be great to interact with that community as well.”

Besides trying to flesh out the physics of these fundamental interactions, Payne also tests nanoparticles used in consumer products and industrial processes to see how they affect cells and proteins. For example, paints, pigments and white food colorings often contain nanoparticles.

Many of these nanoparticles trigger the body to produce reactive oxygen species—free radicals such as peroxides and superoxides. A buildup of these molecules can cause oxidative stress, damaging healthy cells and DNA—the phenomenon antioxidant foods are supposed to address.

“These experiments are more applied—we’re using common nanoparticles that people are often exposed to—and a lot of people ask me what this means for them,” said Payne. “I tell them not to stop wearing sunscreen, since those nanoparticles don’t penetrate the skin. But my work does raise concerns for those producing or processing the nanoparticles and potentially inhaling them on a daily basis.”

In another line of practical research, Payne is developing electrically conductive polymer wires thinner than a single cell, which could have a range of applications from treating brain disorders to helping tissues heal. One example is deep brain stimulation, where wire leads are fed deep into the brain to relieve motor symptoms of Parkinson’s disease. A smaller, flexible wire would be less disruptive than the larger, stiffer, metal wires currently in use.

Payne says she is excited to come to Duke because of the proximity of an outstanding medical school to the engineering laboratories.

“I also think it will be very good for my research to be surrounded by materials engineers,” said Payne. “Duke also has a very strong chemistry department—I already know several of the faculty there—so it will be great to interact with that community as well.”

As for the teaching side of being a faculty member, Payne has had 32 undergraduates work in her laboratory over the past decade, with many publishing papers and earning graduate fellowships as a result of their research. Whether on the undergraduate or graduate level, her lab offers an interdisciplinary experience to all of her students.

“Whether it’s building microscopes, growing cells, isolating DNA or functionalizing nanoparticles, my philosophy is that my students get to try a bit of everything,” said Payne. “Other laboratories might give a more in-depth experience in a single area, but I take students from most any related discipline and help them get their hands wet in all sorts of different areas.”