Posted on July 22: Biophysicist uses laser optics to study the dynamics of cells

By Shelly Easton, July 22, 2003

    Cecile Fradin
The Swiss and French Alps are what physics professor Cecile Fradin misses the most since coming to McMaster 20 months ago.

Hamilton's infamous mountain just isn't the kind of rugged terrain Fradin, a native of France, considers a challenge.

Instead, Fradin's new challenges are found in a newly renovated research lab in the Arthur Bourns Building where she is conducting research into cellular dynamics.

Her field of study, biophysics, is an amalgamation of biology and physics.

Fradin, who holds a Canada Research Chair in Molecular Biophysics, was always drawn to the area of optics in her studies that have taken her from the heart of Paris, to Pisa, Italy, New York and Israel.

"I've always liked experiments that involved optics," she says. "I like to be able to see things with my own eyes instead of reconstructing them."

Fradin's research involves using laser optics to study the dynamics of biological systems such as cells.

"We're trying to look at how fast proteins are moving inside cells, how fast they can be transported across membranes and how fast they can change conformation," she says. "There are many processes where we know what proteins are performing but we don't know how it is occurring. Another important question is where is the energy coming from to make this happen."

To picture a cell, imagine you have a box full of little Lego bricks (the proteins), she suggests. The bricks have different shapes and different colours that can assemble to form large organized structures and these bricks and larger structures are moving. In her experiments, Fradin uses light or fluorescent microscopy to observe the fluorescent emission coming from one specific type of brick.

To make the desired bricks fluorescent, a possible method is to insert modified DNA into the cell, which then directly produces fluorescent proteins. "The cell is doing the work for us," she notes.

The goal of Fradin's research is to better understand some of the precise cell processes that are at work. For example, she is keenly interested in nuclear transport or the transport of macromolecules in and out of the nucleus to other areas of the cell. One of her current research projects is examining how quickly a protein crosses the nuclear membrane. Another experiment will provide information on the fluctuation of molecules  how fast can a protein change its shape.

"A long-term goal is to look at how we can use biological bricks to construct our own bricks to do what we want instead of what the cell wants," she explains. "Proteins self-assemble. If we can figure
out how to use them to do what we want there is lots of potential."

Understanding these processes will eventually aid in the development of gene therapies that could contribute to healthier humans or contribute more knowledge about conditions such as viral infections. As well, the new experimental techniques she is working with may eventually be transferred to the high-tech industry.

She is already integrating two state-of-the-art technologies  fluorescence correlation spectroscopy with fluorescence resonance energy transfer  to measure protein movements. The technique is groundbreaking and will contribute to the development of highly skilled researchers in the evolving fields of biophysics and laser optics.

Fradin acknowledges her love of science comes from "being born in a scientific family." Her mother, a math teacher, played an integral role in her pursuit of the sciences.

She says her early scientific interests also evolved from delving into the many scientific journals her parents subscribed to and which she eagerly read.

Journals that offered mathematical puzzles and Science et Vie, the French equivalent of Scientific American, were influential as was La Hulotte, a small periodical that she still reads. Each issue is devoted to a comprehensive description of a small animal.

During her undergraduate and PhD studies, Fradin focused on a combination of mathematics, physics and chemistry because she didn't feel biology was an "exact science." It wasn't until her post-doctoral studies that she considered the combination of biology and physics to be something she wanted to pursue.

"It seemed that biology, when studied with a physicist's approach, could be an exact science after all. So I decided to start a biophysics project, studying the transport of proteins inside cells with fluorescence microscopy, in the group of Michael Elbaum at the Weizmann Institute of Sciences in Israel."

Her post-doctoral studies required her to study biochemistry, a challenging but necessary frustration that convinced her she had found the right research area.

Now, in addition to her research, she is working with colleague Paul Higgs, the Canada Research Chair in Bioinformatics, to develop a new biophysics stream for McMaster undergraduates.

Fradin says developing the new study stream is both rewarding and an opportunity to step back and take a look at the big picture.

"It's exciting to develop a new course; there are no textbooks that cover the whole topic and it is interesting to do the synthesis and collaboration," she says. "It will be good for my research too."

Photo credit: Chantall Van Raay

This story originally appeared in the March 2003 issue of the McMaster Review