Wisconsin scientists find a way to make human collagen in the lab

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Public release date: 13-Feb-2006

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University of Wisconsin-Madison

Wisconsin scientists find a way to make human collagen in the lab

MADISON - Of all of the materials that make up our bodies, nothing is

more ubiquitous than collagen.

It is the most important structural protein in the body, reinforcing

connective tissue, bones and teeth, and forming long, fibrous cables

to strengthen tendons. Collagen forms sheets of tissue that support

the skin and every internal organ. There is nothing in the body, in

fact, that does not depend in some way on collagen.

In medicine, collagen from animals, principally cows, is used to

rebuild tissue destroyed by burns and wounds. Commonly, it is

employed in plastic surgery to augment the lips and cheeks of

starlets and others seeking perpetual youth. Catgut, the

biodegradable sutures made from cow or horse intestines and used in

surgery to minimize scarring, is also a form of collagen.

But for such a commonplace and useful protein, collagen has defied

the efforts of biomedical researchers who have tried mightily to

synthesize it for use in applications ranging from new wound-healing

technologies to alleviating arthritis. The reason: Scientists were

unable to synthesize the human protein because they had no way to

link the easily made short snippets of collagen into the long,

fibrous molecules necessary to mimic the real thing.

But now a team of scientists from the University of Wisconsin-

Madison, writing this week (Feb. 13, 2006) in the Proceedings of the

National Academy of Sciences (PNAS), reports the discovery of a

method for making human collagen in the lab.

The work is important because it opens a door to producing a material

that can have broad use in medicine and replace the animal products

that are now used but that can also harbor pathogens or spark

undesirable immune responses. What's more, the new work may also lay

the foundation for applications in nanotechnology -- such as

microscopic sensors that could be implanted in humans to confront the

effects of disease -- because it gives scientists a way to precisely

manipulate the lengthy molecules and add elements to collagen that

confer new abilities.

" We can make collagen that duplicates nature exactly, but we can

diverge from that when it is desirable, " says T. Raines, a UW-

Madison professor of biochemistry who, with postdoctoral fellow

W. Kotch, authored the new PNAS study.

Scientists have been seeking a way to make synthetic collagen for at

least 30 years. In clinical settings, human collagen would be

preferred over bovine collagen because the material now gleaned from

cows can prompt an unwanted immune response in patients and it can

harbor animal pathogens that might infect humans.

The Wisconsin team discovered a way to make the long, slender

collagen molecules, in essence, by having the protein assemble

itself. What was required, Raines explains, was a way to give the

collagen snippets that scientists could easily make a way to " self

assemble " into the long, thin fibers of native collagen. The

Wisconsin team was able to modify the ends of the snippets so they

could fit together and stick to form long collagen fibers.

" Now we can make synthetic collagen that's longer than natural

collagen, " says Raines, who previously authored a paper in the

journal Nature that demonstrated how to make synthetic collagen that

is stronger than natural collagen. " We just don't have to take what

nature gives us. We can make it longer and stronger. "

In medicine, synthetic human collagen could be used as " solder " to

speed healing of large wounds. In the context of nanotechnology,

collagen has appeal as a type of nanowire because it is thin --

thinner even than the vaunted carbon nanotubes hailed by

nanotechnologists -- and long.

Coated with gold or silver, human collagen could form the basis of

implantable electric sensors. By attaching certain biological

molecules to the wire, it would be possible to create sensors that

might, for example, quickly alert a diabetic to falling insulin

levels. Similarly, equipped with molecules to recognize specific

pathogens, such a sensor could stand perpetual guard in the body and

provide instant warning of invading viruses or bacteria.

" We can have total control of what goes on these very thin extended

fibers, " says Raines. " We are able to build these molecules up one

atom at a time and we can manipulate them in very precise ways. "

The new Wisconsin study, which was supported by grants from the

National Institutes of Health, lays a foundation for bringing human

collagen to the clinic, says Raines. But he notes there is still some

work to be done to perfect the technology.

For example, while the new work enables the researchers to make

collagen molecules that are long and strong, ways to precisely

control the self-assembly of collagen to molecules of a specified

size remain to be worked out, according to Raines.

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-- Terry Devitt (608) 262-8282, trdevitt@...

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