Pour-on nanotechnology stops bleeding in seconds


10 October 2006

Researchers at the Massachusetts Institute of Technology, US, have created a liquid that stops bleeding in any tissue in a matter of seconds. It is a discovery that they claim has the potential to revolutionise surgery and emergency medicine and could even make it easier to reattach severed limbs.

Rutledge Ellis-Behnke and colleagues worked from the nanoscale, using individual amino acids to create a self-assembling peptide. It looks exactly like water but when applied directly onto injured tissue it halts bleeding. This is the first time nanotechnology has been used to control bleeding, claims Rutledge.

The remarkable discovery was made by accident during an experiment in which the liquid was used to stimulate nerve repair in the brains of rats. Ellis-Behnke's group, whose work is focussed on central nervous system repair, found that the liquid mended the nerve cells as predicted, but caused a strange side effect.  

'When we used the liquid during the surgery we thought that the animals had died. The bleeding in the brain stopped and that normally indicates that the heart has stopped beating,' Ellis-Behnke told Chemistry World. 'When we realised what had happened, we made a note of it and then went back to the drawing board to test it.' 

In tests on skin, liver, lung, blood vessels and a variety of other tissue, Ellis-Behnke and his colleagues were able to use the liquid to halt bleeds in less than 15 seconds. The mechanism for this ability remains something of a mystery. 

'It isn't clotting that we're seeing. We tested for all of the things you find in all blood clots; fibrin, thrombin and platelets and none of them were there,' said Ellis-Behnke. 'Either this is acting as some kind of molecular band aid or we are stopping bleeding via a completely new direction that we have never seen before.'

Once the liquid touches an internal organ, it forms a gel; the amino acids assemble into fibres and stop the bleed. The degradable peptide then breaks down into non-toxic products as the tissue heals. 

These products can even be used by cells to rebuild damaged tissue, according to the researchers. During the study, the liquid was used successfully internally and externally, before breaking down to be incorporated into the healed tissue or excreted in the urine. 

Surgeons currently spend up to 50 per cent of their time during surgery packing wounds in order to reduce or control bleeding, so if Ellis-Behnke's liquid works it would make a profound difference. Promising results in an animal model mean that human trials could begin in as little as three years, he said. 

'This could even be used on the battlefield,' added Ellis-Behnke. 'If a limb is removed, this could be applied to the severed limb as well as the wound on the body. It would stop the drying out and decay of the tissue and keep it clean so it would be easier to reattach.' 

Victoria Gill

References

R G Ellis-Behnke et al., J. Nano. 2006, DOI: 10.1016/j.nano.2006.08.001

Polyphosphate crucial for clots

The linear polymer polyphosphate plays an important, but previously unsuspected, role in blood coagulation.