Using Nanobiotechnology to Map Changes in RNA
By Claire Ricks
Physics, engineering, and biology aren't often used in tandem to describe scientific
research. But this interdisciplinary work and novel way of combining techniques in the
sciences is what makes Professor of Applied and Engineering Physics at Cornell
University Lois Pollack's work so exciting.
A way to think about nanobiotechnology, Pollack said, "is taking fabrication techniques
from physics and engineering that have been developed for a very long time in those
areas and applying them to answer questions about molecules. It's work that's at the
interface of all three fields that no one has thought to put together until now."
While the applications of this extend far and wide, Pollack's research focuses on how
RNA strands get the shape they need to carry out their jobs in cells. RNA, or ribonucleic
acid, is involved in regulating the expression of certain genes. Their shape—how they
fold—determines how and what molecules they bind to, which ones can catalyze to make
certain proteins or to turn a gene on or off, like a light switch. The specific RNA Pollack
is looking at can regulate gene expression in bacteria, but not in humans, making them
targets for new antibiotics.
"What's really interesting about this," Pollack says, "is the technology that allows us to
understand how these switches work, so that you could design a drug that would lock the
switch in the on or off position, [thus preventing the bacteria from infecting humans]. All
the biological molecules fold, including RNAs and DNAs. The technique we developed
is generic in that you can apply it to all these different structures," Pollack added.
Nanofabrication, manufacturing on a nano-scale, is combined with incredibly powerful xray sources to show what shapes the RNA takes as it folds. Pollack's team actually makes
nanofabricated structures to initiate RNA folding, structures which they put into a large
particle accelerator that generates x-rays. Traditionally these are all physics-based
methods but are now being used to study biological problems.
Since x-ray wavelengths are about the size of an atom, Pollack's team can see things
close to that level. It's not quite possible yet to get an image with atomic resolution, but
we can detect structures and measure changes within those structures, explains Pollack.
"X-rays are a terrific probe, but you have to have a sample volume. One way is to confine
the sample by finding it with the x-rays, and figuring out when you start the reaction. To
help with this process, we use fluidics, another physics-based technique that uses fluids to
perform functions similar to those electronics.
To really understand biology, you need to be able to measure shapes and determine how
molecules acquire shapes and how those shapes change over time," said Pollack. "That's
really what it's all about—molecules finding each other like two pieces in a 3-D puzzle
that have a perfect fit. But it's all dynamic and everything's moving, and it's not so easy to
figure out how all these things fit together. That's why we're relying on the x-ray and
well-developed fabrication techniques that have been around forever and combining them
with biology."
Come learn about the latest research in cell biology and DNA sequencing on July 7th,
6:00 p.m. at the Mountain Village Conference Center, hosted by the Telluride Science
Research Center. Admission is free; cash bar starts at 5:30 p.m.