COLUMBIA — Picture the smallest thing you can see with your eyes. Maybe it's a grain of salt or a speck of dirt on the ground.
Now, think of something 1,000 times smaller. A molecule.
Even though molecules cannot be seen individually by the human eye, they make up most of the oceans and the atmosphere.
Two MU researchers have developed a 3-D microscope that looks at proteins in cell membranes on a molecular level. The information gathered from the observations could potentially advance drug development, giving scientists more effective medical applications.
Gavin King, assistant professor of physics and astronomy at the College of Arts & Science at MU and Krishna Sigdel, a postdoctoral fellow in the Department of Physics worked together to create the 3-D atomic force microscope.
In a traditional atomic force microscope, a silicon nitride tip pokes at the surface of the molecule. The tip, which is one-thousandth the thickness of a hair, is connected to a cantilever that moves up and down like a diving board in response to the force applied by both scientists and the protein.
To create the 3-D microscope, King and Sigdel added a laser that hits the tip and scatters, to tell researchers where the tip is located in space. The results show how the membrane proteins move and interact.
"The importance is potentially long-term in terms of developing new tools to allow us to understand nature ... and potentially map complex dynamics of biological molecules," King said.
The idea came from a technological development in King's initial doctoral research. He found that the problem with a traditional force microscope is that results are incomplete and one-dimensional.
King's improved microscope, however, allows sample membranes to be in a near-natural state of salt water or saline solution. Previously, samples were eithercrystallized or frozen, which made the results less realistic.
When observing membrane proteins through the microscope, the structure of the protein might change depending on the environment, such as changes in voltage or adding chemicals to the proteins being studied.
The microscope measures these changes in 3-D and shows exactly how the membrane protein responds to its surroundings.
"We could potentially monitor structural change in three dimensions, in real time and with high precision in near-native conditions," King said.
Pioneering new ways to observe the world is both challenging and exhilarating, the researchers said.
"When you're at the frontier it is hard to predict what the next step is going to be," King said. "So when you have something with a new capability, one can dream about the applications, but it is really going to be speculative. That's what makes it exciting."
Supervising editor is Jeanne Abbott