Clay "Smart Bandage": Injected into the body, stops bleeding in one minute

When severe trauma leads to internal bleeding, every second counts. The medically termed "golden hour" refers to the critical window between injury and effective treatment. However, for deep internal bleeding, traditional external pressure hemostasis is often ineffective. Recently, a research team at Texas A&M University drew inspiration from ancient remedies and developed an injectable "smart bandage" using clay. This bandage rapidly expands and stops bleeding within the body, reducing clotting time from six or seven minutes to one or two minutes.

In the United States, traumatic injury is the third leading cause of death after heart disease and cancer, with a large number of deaths caused by uncontrollable bleeding. Hemorrhagic shock can be fatal in a short time, with many patients dying within one to two hours of injury. To address this challenge, Professor Akilesh Gahavar of the Department of Biomedical Engineering at the university, along with Professors Duncan Maitland and Tyler Weil, are developing a series of injectable hemostatic materials specifically designed to treat deep internal bleeding that is difficult to manage using traditional methods.

The key material in the study was surprising: clay. In fact, using clay to stop bleeding is not a modern invention. Ancient civilizations in China, Mesopotamia, Egypt, Greece, and Rome all record the use of clay paste applied to wounds to stop bleeding. Modern science has revealed the underlying principle: the silicate particles in clay have water-absorbing and tissue-adhesive properties, which accelerate blood clotting.

However, directly applying clay particles to internal bleeding poses significant risks. Nanoscale silicate particles can be washed away by the bloodstream, traveling through blood vessels to uninjured areas and causing fatal blood clots or embolisms. The key to technological breakthroughs lies in precisely delivering clay to and securing it at the bleeding point.

The research team proposed two innovative solutions.

The first approach combines nano-silicate particles with an expanding foam. This foam remains stable before being injected into the body, but upon contact with body temperature, it rapidly expands and fills the wound space, sealing the ruptured blood vessels. Because the foam forms a unified structure, the clay particles are firmly fixed and will not detach or spread.

The second approach employs a "microband" design. Multiple strip-shaped structures are coated with coagulation nano-silicates. Each strip is made of two different materials, one of which is sensitive to body temperature. Upon injection, the sensitive side contracts and curls, and the multiple strips intertwine to form a foam-like structure. Even if a single strip detaches, its tiny size is insufficient to block major blood vessels, thus minimizing the risk of clotting.

Two recent studies published in *Advanced Science* and *Advanced Functional Materials* show that these new hemostatic dressings can reduce bleeding time by nearly 70%. Normal human blood takes six to seven minutes to clot, but with these materials, clotting time is reduced to one to two minutes.

The research team's ultimate goal is to develop a simple enough life-saving device that injured individuals can use immediately after injury. This means that they cannot rely on sophisticated equipment in the operating room; the materials must be fast, effective, and require no specialized operation.

"If these materials can get into ambulance first aid kits and soldiers' backpacks, they could save a lot of lives," Gahavar said. "If they can save 30% to 40% of patients with hemorrhagic shock, that would be a huge achievement."

Currently, this research has received funding from the U.S. Department of Defense and the National Science Foundation. The team is continuously advancing the clinical translation of the technology, which is expected to provide new hemostasis solutions for trauma first aid, battlefield first aid, and everyday accidental injuries in the future.

Source: Texas A&M University