Susan Daniel looks for ways to harness the unique properties of the cell membrane.
Constructed of a double layer of molecules called a lipid bilayer, cell membranes, like skin, perform crucial functions such as keeping harmful molecules out but letting necessary molecules in. Daniel is investigating ways to put this selective permeability to work.
Daniel works with lipid bilayers synthesized on a solid surface because, like real cell membranes, they allow individual lipids to move laterally within the membrane. “This mobility is important for signal communication,” she says. “These materials could have applications as biosensors and novel devices that can tell us information about how proteins or viruses bind to the cell membrane and how that might translate to the formation of disease.”
By creating a lipid bilayer inside a microfluidic channel, for example, it could become a biosensor capable of distinguishing specific toxins. “Tetanus and cholera toxins bind to the same receptor on the surface of the cell membrane, but they are different shapes,” explains Daniel. “We can create lipid bilayers that control which molecule will contact the membrane receptor so if it binds, we know which one it is.”
Daniel has also discovered a way to use solid supported lipid bilayers to separate membrane species, which could lead to new methods for membrane protein purification. Gel electrophoresis, the current method for separating proteins, changes their structure, and so their functionality, by removing them from the cell membrane and subjecting them to harsh processing. But by performing the electrophoresis within a lipid bilayer with controllable properties, Daniel has found she can separate cell membrane species that retain their functionality.
“Hopefully these lipid bilayers can be used to separate protein species, which would be useful in proteomics, or as a diagnostic tool to find misfolded proteins,” says Daniel. “Or as another means to crystallize transmembrane proteins, which are currently the most difficult protein crystal structures to obtain.”
When she can find free time, Daniel likes to get outside. “My husband and I have been really enjoying all the beautiful places around here. You can hike in the gorges or boat on the lake,” she says. “We’ve been snapping pictures at Treman State Park and sending them to all our friends saying, ‘Look where we live.’”
For Daniel, Ithaca’s natural beauty is the icing on the cake that drew her here. “Cornell is an awesome place to be. It has great infrastructure, like a fantastic state-of-the-art nanofabrication facility and the high-energy synchrotron source. The people here are fantastic. I’ve been reaching out to other departments, other researchers, and there’s just possibilities all over the place to do really interesting, collaborative science,” she says. “I love that Cornell is in a little town and not a giant city. I prefer a more rural environment. I can’t think of another school that combines all these things into one.”
Prof. Daniel's Web page
