Science & Technology
Soldering offers a new better way to treat wounds.
If you cut yourself, your options are to reach for a plaster or, if the cut is nasty, to go to a doctor to have it stitched or glued.
That seems a rather limited choice.
Medical researchers have been trying to develop another way to join the edges of a wound, inspired by something routinely done to gas pipes and electronics: soldering.
And an innovation developed at the Swiss Federal Institute of Technology (eth) in Zurich, in co-operation with the Swiss materials-science institute Empa, suggests this might soon become a practical reality.
In soldering, an intermediate material is heated until it melts and bonds with the two surfaces that are to be joined.
The material of these edges has a higher melting point and remains solid (otherwise it would count as welding).
For tissue, the intermediate material is not a metal alloy, but a paste of biocompatible material, such as albumin, a protein that is an important constituent of blood.
When heated, the paste develops chemical bonds with living tissue on both sides.
As healing progresses, the two sides reconnect and the paste is removed by the body's natural cleaning procedures.
Closing wounds by soldering has several important advantages, says Oscar Cipolato, a phd candidate at eth, who presented preliminary results on April 5th at the Photonics Europe conference in Strasburg, France.
The bond it produces is strong and watertight, something that cannot be guaranteed with stitches.
If a wound is interna -- after surgery, for instance -- a leak could cause an infection.
But soldering tissue has turned out to be difficult in practice, which means it is not commonly done.
Heating the soldering paste is done by shining a laser onto it, from which the paste absorbs energy.
But controlling the heating precisely is tricky.
The paste needs to reach about 80°c to work.
If the temperature is too low, the soldering material will not fully melt and the bond will be weak.
But if it is too high, it risks burning the surrounding tissue.