Major, uncontrolled blood loss can have major ramifications everywhere from the battlefield to the operating theatre. While blood-clotting medications can be used to stem the flow, often their purpose is thwarted by conflicting anti-coagulating drugs that thin the blood instead. But now scientists have developed a promising new hydrogel infused with snake venom that is drawn to the wound and shuts down bleeding in a matter of seconds.
"It’s interesting that you can take something so deadly and turn it into something that has the potential to save lives," says Rice University chemist Jeffrey Hartgerink.
Hartgerink and his team developed a nanofiber hydrogel that features batroxobin, a venom found in two species of South American pit viper. The blood-clogging abilities of batroxobin were first discovered in 1936 and in the time since it has been used in therapies to treat thrombosis and to control bleeding during surgeries. While its blood-clotting properties are long established, it was combining it with another long-term research project at Rice University that has brought out one of its more promising applications.
For some time, Rice researchers have been working on injectable hydrogel scaffolds built from peptide sequences that mimic natural processes to heal wounds with natural tissue. The baxtrobin used in this research isn't derived from hissing, real-life snakes, but is produced by genetically modified bacteria and then purified to rid it of other dangerous toxins.
By mixing their baxtrobin and nanofibers and loading them into a syringe, the researchers found themselves with an injectable liquid they've dubbed SB50. Testing showed that as the liquid was injected at the site of a wound, the nanofibers assemble themselves into a gel and the new material stopped bleeding within six seconds. Poking at the wound in the minutes following did not see the wound reopened.
One problem in particular the researchers say the new hydrogel can help overcome is when working with patients taking the anti-coagulant drug heparin, which blocks an enzyme called thrombin that instigates natural clotting and prevents blood loss.
"Batroxobin is also an enzyme with similar function to thrombin, but its function is not blocked by heparin," says Hartgerink. "This is important because surgical bleeding in patients taking heparin can be a serious problem. The use of batroxobin allows us to get around this problem because it can immediately start the clotting process, regardless of whether heparin is there or not."
Batroxobin is already approved for use by the US Food and Drug Administration, though Rice's new hydrogel is not. The researchers say several more years of testing are needed before it is cleared for clinical use.
The research findings were published in the journal ACS Biomaterials Science and Engineering.
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