Purifying proteins with new chromatographic
techniques
by Paul Sorenson and Joseph Carlson
Special coverage
From biomedical engineering and medical device development to genetic research
and biological process technology, IT researchers play a major role in the growing
field of biotechnology. Here is a look at 13 of the most innovative projects
underway.
Like farmers separating wheat from
chaff, scientists developing new drugs must find ways
to isolate useful proteins from other molecules, including
undesirable toxins and molecular debris.
Liquid chromatography, the technique normally used
in this process, is limited by the type and temperature
of material with which it can be used. But a team of
IT researchers is developing new materials that will
remove those limitations and broaden chromatography's
effectiveness across a wide range of applications.
Liquid chromatography works through selective adsorption,
explains chemistry professor Peter Carr, who leads the
team of researchers developing the new technique. In
a chromatograph, particles of silica gel are packed
together in a dense columnar mass that acts as a selective
adsorbent. As fluid moves through the column, molecules
of different types pass through it at varying rates.
By carefully adjusting the surface chemistry of the
silica particles, scientists can design chromatographic
media to purify and analyze a wide range of substances,
including proteins and amino acids.
Although liquid chromatography has been widely used
for years, Carr and Alon McCormick, an associate professor
of chemical engineering and materials science, discovered
that the technique could be improved by using zirconia
as the chromatographic media rather than silica. For
example, zirconia-based liquid chromatographs can function
at higher temperatures and process materials under more
acidic and basic conditions.
According to Carr, zirconia-based chromatographs are
also more useful in biotechnology applications because,
unlike those based on silica filtering agents, they
can be sterilized with a strong base to remove pyrogenics,
the toxic by-products of protein harvesting that “stick
like hell to everything."
The new media will also improve liquid chromatography's
applications in environmental and chemical analysis,
forensic science, biochemistry, and industrial chemistry
laboratories, he adds.
Carr began exploring the use of zirconia in liquid
chromatography during a collaboration with 3M in the
early 1980s. The company eventually pulled out of the
project, leaving Carr to continue the research with
McCormick and other colleagues, including Professor
Michael Flickinger and Assistant Professor Anuradha
Subramanian, at the University's Biological Process
Technology Institute.
Since then, Carr and McCormick have focused on the
complex chemical analysis and modifications required
to develop zirconia as effective chromatographic media,
earning several patents for their work.
In 1995, the University licensed several of those patents
to ZirChrom Separations, a company founded by Carr and
a former graduate student to manufacture the zirconia-based
chromatographs. According to Clayton McNeff, ZirChrom's
vice president and director of research, most of the
company's sales are to large pharmaceutical corporations
like Novartis.
ZirChrom also has earned state and federal research
grants to develop the technology further. With that
funding, the company is sponsoring a collaboration with
McCormick to discover ways to improve the raw colloidal
materials used to create the zirconia. Another grant
supports a joint project with Subramanian to develop
techniques for purifying monoclonal IgG antibodies and
other larger molecules.
Future University-industry collaborations are inevitable,
says Carr.
"The biotechnology applications alone [for this
new technique] are staggering,” he says. “We've
only just begun exploring the possibilities."
