VOLUME 7, NUMBER 3
Polymers are everywhere.
Run your fingers through your hair and you've mussed a natural
polymer. Take a bottle of soda from the fridge and you've put
your hands on the synthetic polymer PET, short for poly(ethylene
Ubiquitous they are, but polymers
are far from ordinary. Few understand this better than Wei Chen, Mary E. Woolley
Assistant Professor of Chemistry. Chen is studying ways to improve PET for use
as a biomaterial--for beyond housing thirst-quenchers, PET plays a starring
role in medical science. It is the material of choice for human implants, such
as artificial heart vessels.
But PET has problems--biocompatibility
problems. Like any foreign material that finds its way into the human body,
implants made of PET set off biological alarms. The body, sensing an invader,
sends out an army of proteins and cells to attack and surround the perceived
intruder. As soon as a PET implant has been sutured into place, these microscopic
foot soldiers begin their onslaught, coating surfaces and clogging grafted arteries.
To solve this sticky problem, scientists "are looking for materials that the
body will like," says Chen.
Now, a three-year, $136,000 grant
from the National Institutes of Health is allowing Chen, and a select group
of Mount Holyoke students, to address the biocompatibility problems that plague
PET by designing materials for organ and tissue replacement that will repel
the proteins and cells that tend to foul artificial implants. To do this, Chen
and her students spend countless hours working to develop the ideal protein-repellant
material by choosing different ways to bond protein-repellant PEG, another polymer,
to the surface of PET.
The bonds formed between PEG and
PET aren't the only ones made in Wei Chen's lab. "As much as a working relationship,
Professor Chen really fosters a sense of community," says Anuja De Silva '03.
"She encourages us to do things together and ask each other for help." Along
with De Silva, Mamle Quarmyne '03, Piwai Dakwa '04, Surangkhana Martwiset '03,
and Kwansima Quansah '04, are the members of what Chen has dubbed the "polymer
gang." This tightly knit group has, under Chen's tutelage, become captivated
with polymer chemistry.
"Gang" member Quarmyne has been
using poly(vinyl alcohol) to modify polymeric materials--another major focus
of Chen's work. The research has implications for an array of industrial and
commercial applications. (Imagine, for example, an airplane made of a substance
that repels water: no more deicing delays.) Last summer, in response to commercial
interest in the research done by Quarmyne and Bryony Coupe '02, the College
filed a U.S. patent on the work.
It was a big summer for Quarmyne,
who also attended the national meeting of the American Chemical Society (ACS).
There--out of a field of hundreds of professors, scientists, and graduate students--Quarmyne's
presentation detailing her poly(vinyl alcohol) work was named one of the top
six "posters" in its division. She is philosophical about her success. "Doing
independent work with Professor Chen, we present all the time. If you keep presenting
the material, you get very comfortable with it."
Because of the complex, interdisciplinary
nature of polymer chemistry, Chen usually begins working with students in their
third year. De Silva, however, began working with Chen during the summer after
her first year at Mount Holyoke. The following summer De Silva interned at Harvard.
This year she is doing a thesis with Shaw Ling Hsu, professor of polymer science
and engineering at the University of Massachusetts, Amherst. Like Quarmyne,
De Silva will go to the ACS meeting this spring, where she is scheduled to deliver
a talk on her research with Hsu. How does an undergraduate feel about addressing
a roomful of prominent scientists? "I'm kind of nervous about it," says De Silva,
"but if you have the results, you just present them."
"Results" are key for Chen, who
insists that all of the students who work in her lab do productive research
and publish their findings. De Silva, Quarmyne, and the other members of the
polymer gang have clearly benefited from their mentor's expectations, as they
apply to prestigious graduate programs with at least one, if not two, scholarly
publications on their vitae.
For her part, Chen enjoys being
able to say to a student, "Do you realize you are the first person on Earth
to get this result?" Such moments, the chemist believes, can be transformative
in the life of a young scientist.