| A MAT of polymer fibers
designed to help wounds heal could spell the end for traditional wound dressings,
say British scientists. The fine web of fibers, which is sprayed on, lets
wounds heal by encouraging the formation of a strong skin structure rather
than weaker scar tissue.
When skin is punctured, the damage often destroys
the weave-like structure of collagen that gives skin its strength. But
when the body tries to patch up the wound, an evolutionary legacy means
it acts in haste: in ancient times, if people's wounds did not heal quickly,
they were likely to die.
So instead of rebuilding the complex collagen weave
as before, the body creates a quick fix by producing thin, aligned strips
of collagen. When skin cells grow on this, they produce the pale, less
flexible material we know as scar tissue, rather than normal skin. Now
Electrosols, a biotechnology company based in Haslemere, Surrey, England
has developed a spray it believes could help wounds heal without scarring.
The spray produces a fine web of biodegradable polymer
fibers that collagen-making cells called fibroblasts can grow on. As more
and more fibroblasts grow on the polymer webbing, they produce a regular
collagen structure, much like that in normal skin. Electrosols researchers
believe that controlling the formation of collagen in this way will lead
to normal skin growth instead of scarring.
To make the spray, the company mixes ethanol and
a biodegradable polymer -- such as polylactic acid -- in a small semiconducting
container, and then gives it an electric charge by putting an electric
field across the container. Because the wound is at a far lower electrical
potential than the polymer, the solution is attracted to the skin surface
and flies out through tiny nozzles, producing fine, light fibers, each
of them 5 micrometers in diameter.
The fibers have the same charge so they repel each
other, making them regularly spaced. This initial polymer fiber mat wouldn't
necessarily have any bearing on the final scar. Collagen is organized
and reorganized continuously, and a whole range of things governs that.
New Scientist, 8 January
2000
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