Hong Kong and American scientists have accidentally discovered a submicroscopic material that can stop bleeding within 15 seconds. The experts from Massachusetts Institute of Technology and the University of Hong Kong made the discovery while working on a brain-cell regrowth project earlier this year. Application of this material during surgery could reduce the time doctors spend on controlling bleeding, which is usually half the time spent at the operating table. International journal Nanomedicine published the finding that described the first time scientists had been able to use a simple biodegradable liquid to stop bleeding in wounded rodents within seconds. When the transparent liquid containing protein fragments called peptides was applied to open wounds, the peptides reassembled into a 'nanoscale' protective gel that sealed the wound and stopped bleeding. A nanometre is about a millionth of a millimetre. Once the wound healed, the non-toxic gel broke down into molecules that the body's cells could use to repair tissue. But the researchers still do not understand the exact mechanism of the liquid's action. They applied the material to brain, liver, skin and spinal-cord tissue of rats and hamsters and stopped bleeding immediately in almost every case. They estimated that it would take three to five years before clinical trials began and at least 10 years before it was widely used in hospitals. 'In performing a surgical operation, doctors have few effective methods to stop bleeding without causing other damage,' said So Kwok-fai, chair professor of HKU's department of anatomy. Present tools used to halt bleeding in surgery include pressure from clamps, heat and sponges. 'It is estimated that as much as half of surgical time is spent working to control bleeding,' Dr So said. 'But with our new discovery, we believe that the time to perform an operation could potentially be reduced by up to 50 per cent.' Research team leader from MIT's brain and cognitive sciences department, Rutledge Ellis-Behnke, estimated the new method might cost US$200 to US$300 for a gastric ulcer surgery.