New gauze promotes natural healing

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Biodegradable bandage made from wound-healing proteins.
24 February 2003

PHILIP BALL

"The new dressing never need be removed."

A new bandage mimics the natural tissue that forms as a wound heals. The gauze, made from the blood protein fibrinogen, could be applied as a dressing that need never be removed. The body would treat it simply as part of normal healing, gradually dissolving it as new skin grows over the wound.

During natural blood clotting at a wound, an enzyme converts fibrinogen into a web of insoluble fibres of the related protein fibrin. This mesh protects the injury from infection and stops bleeding.

Gary Bowlin and colleagues from Virginia Commonwealth University in Richmond, USA, have devised a way to spin extremely fine fibrinogen fibres1.

They extract the protein from human or cow blood and dissolve it in an organic solvent. They then squirt a jet of this solution from an electrically charged hypodermic needle — the electric field stops the stream breaking up into droplets.

As the jet flies through the air, the solvent evaporates and the fibrinogen molecules stick together into fibres a thousand times narrower than a human hair, at just 80 millionths of a millimetre wide. This is about the same thickness as fibrinogen fibres in normal blood clots.

These fibres hit a rotating steel drum, and gather into a tangled mat. The researchers remove the mat when it gets to about a tenth of a millimetre thick, by which time it is strong enough to act as a wound dressing.

A sheet of this fibrinogen gauze should both stop bleeding quickly and speed up the healing process, claims Bowlin's team. It should act as a scaffold into which tissue-forming cells can grow and move. A snippet, for example, would help staunch shaving nicks.

The next step is to make shaped biodegradable scaffolds to guide the regrowth of damaged tissues. Bowlin and colleagues hope to combine different kinds of material in one mesh, including the skin protein collagen and growth factors, to stimulate the formation of specific tissue types.

References

Wnek, G. E., Carr, M. E., Simpson, D. G. & Bowlin, G. L. Electrospinning of nanofiber fibrinogen structures. Nano Letters, 3, 213 - 216, (2003). |Article|