Add snake venom to the growing list of new ways to help stop bleeding, as a team of researchers from Rice University have found that adding batroxobin, a toxin produced by two kinds of South American pit viper, to a nanofiber hydrogel enhances its abilities as a coagulant.
As lead author Vivek Kumar from the Rice Departments of Chemistry and Bioengineering and his colleagues reported recently in the journal ACS Biomaterials Science and Engineering, they took a self-assembling peptide hydrogen capable of preventing blood loss on its own, then added 50 μg/mL of batroxobin in order to make it even more effective as a clotting agent.
The resulting hydrogen, which has been called SB50, is injected as a liquid but quickly becomes a gel that conforms to the site of a wound, thus keeping it closed. It can promote clotting in seconds, making it useful during surgical procedures – particularly when they involve patients using anti-coagulant drugs to thin their blood.
Hydrogel proves effective, even when anti-coagulants are present
Batroxobin’s value as a clotting agent has been known for decades, Rice chemist and study co-author Jeffrey Hartgerink said in a statement. Since 1936, it has been used to remove extra fibrin proteins from blood to treat thrombosis, as a topical hemostat, and to help determine how long it takes blood to clot in the presence the anti-coagulant drug heparin.
“From a clinical perspective, that’s far and away the most important issue here. There’s a lot of different things that can trigger blood coagulation, but when you’re on heparin, most of them don’t work, or they work slowly or poorly,” Hartgerink explained. “Heparin blocks the function of thrombin, an enzyme that begins a cascade of reactions that lead to the clotting of blood.”
He added that batroxobin is “an enzyme with similar function to thrombin, but its function is not blocked by heparin. This is important because surgical bleeding in patients taking heparin can be a serious problem” This type of snake venom, Hartgerink added, is able to “immediately start the clotting process, regardless of whether heparin is there or not.”
Latest clotting breakthrough still requires FDA approval
The Rice-led team used genetically modified and purified batroxobin to avoid contaminating it with other types of toxins, then combined it with synthetic, self-assembling nanofibers. Next, the substance can be loaded into a syringe and injected into a wound site, where they reassemble into a gel. Tests have demonstrated that it can stop bleeding in as little as six seconds.
Hartgerink said that he and his colleagues believe that SB50 “has great potential to stop surgical bleeding, particularly in difficult cases in which the patient is taking heparin or other anti-coagulants. [It] takes the powerful clotting ability of this snake venom and makes it far more effective by delivering it in an easily localized hydrogel that prevents possible unwanted systemic effects from using batroxobin alone.”
Before the substance can be used clinically, however, it must first be approved by the FDA. While Hartgerink noted that batroxobin on its own has already received such approval, their new hydrogel has not, and the process could require several more years worth of testing before SB50 can be used in hospitals and clinics.
It joins several other recent breakthroughs that could help stop wounds from bleeding faster and/or more effectively than currently available methods. For example, earlier this month, a team from the University of British Columbia created a self-propelled powder that could go against the flow of blood to treat severe bleeding, and a new gel made from algae was shown to effectively stop hemorrhaging in severe wounds far faster than ordinarily.
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Feature Image: Thinkstock
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