Hemorrhage is the leading cause of death following battlefield injuries. There are many forms of commercially available hemostats to date, including sponges, powders, sheets, gauzes, and hydrogels, which exhibit effective hemorrhage control. But none of them can provide fast, temperature-sensitive treatment of hemorrhage in a controllable manner.
Now, researchers from the Terasaki Institute for Biomedical Innovation (TIBI) have developed an injectable, temperature-sensitive, shear-thinning hydrogel (T-STH) hemostat that works rapidly at body temperature to stop bleeding from a wound.
To impart the composite hydrogel with shear-thinning capabilities, the researchers used a polymer called poly(N-isopropyl acrylamide) – due to its temperature-sensitive mechanical properties – and mixed it with laponite, a blood-coagulating agent.
In initial experiments, researchers produced an optimized T-STH formulation, and it was demonstrated that the material could stop bleeding when subjected to quickly changing temperatures, such as during the treatment of traumatic wounds. After injection into the body, the T-STH becomes a solid and hemorrhage-controlling material. When exposed to a cold saline wash, it changes to a soluble material that can easily be washed away.
Moreover, this formulation showed 50% reduced blood clot time over negative controls, was shown to be non-toxic, and degraded at rates favorable for short-term hemorrhage control.
The formulation was further tested in a laboratory model set up to mimic human blood flow. Blood from simulated injuries was collected, and the results showed that the T-STH was significantly able to reduce blood loss at the injury sites and form an effective plug against further bleeding at different blood flow rates. In another experiment, researchers reproduced the results using mouse models with bleeding injuries.
The team says this technology allows anyone to treat victims of traumatic injuries immediately and effectively. Once patient stability is achieved, the T-STH hemostat can easily be removed using a cold saline wash without leaving residues or causing re-bleeding of the wound. The saline wash also allows for the removal of any debris lodged in the wound.
In addition, there is a potential for improvement with the addition of faster coagulants, antibiotics for infection control, and molecules that promote tissue regeneration. There are also possibilities for a sprayable version of the T-STH to treat lacerations and abrasions.
“The development of a temperature-sensitive hemostat enhances the effectiveness and simplicity of immediate treatment for traumatic injury and has the potential to save many lives,” said Ali Khademhosseini, Ph.D., TIBI’s Director, and CEO. “It is one of many ongoing and impactful research efforts from our biomaterials platform.”
- Marvin Mecwan, Reihaneh Haghniaz, Alireza Hassani Najafabadi, Kalpana Mandal, Vadim Jucaud, Johnson V. John, and Ali Khademhosseini. Thermoresponsive shear-thinning hydrogel (T-STH) hemostats for minimally invasive treatment of external hemorrhages. Biomaterials Science, 2022; DOI: 10.1039/D2BM01559E