Toothpaste-like gel stops bleeding when injected into blood vessels

The new biomaterial would replace current treatment options that don’t work for all patients.   

Patients on blood thinning medications or those who can’t form blood clots need medical help to prevent uncontrolled bleeding that can quickly become life-threatening. In a new Science Translational Medicine study, researchers introduce a hydrogel that can rapidly and easily block the flow of blood.

Aneurysms or other forms of uncontrolled hemorrhaging are often treated by inserting a tiny metallic coil into the person’s blood vessel. But for 47 percent of patients who cannot form blood clots this isn’t a permanent solution and they’ll bleed again. This is also no small problem. In 2010 25 million people were prescribed warfarin in the United States, which is an anticoagulant or blood thinning drug that prevents blood clots in patients with heart conditions, stroke risk or risk of thrombosis after an operation.

“Current therapies that try to occlude blood vessels and stop bleeding in cases of internal bleeding do not work for a major segment of population that are on anticoagulant medication or have disorders which prevents their blood from clotting,” says Ali Khademhosseini, professor at Harvard Medical School and Brigham and Women's Hospital. “Our material provides a solution to this issue and allows for a new standard of care that replaces metallic coils, which are expensive and complicated to use.”

Together with Rahmi Oklu, interventional radiologist at Mayo Clinic, Khademhosseini developed the new biomaterial, known as shear-thinning biomaterial (STB), by combining gelatin – which gives it a consistency similar to toothpaste – and nanoparticles.

This is an image highlighting the injectability of the biomaterial through a catheter. The biomaterial can maintain its shape upon injection, only becoming liquid after a force is applied. Inset is a zoomed image of the shear-thinning biomaterial extruded from the catheter tip. Credit: Ali Khademhosseini.
This is an image highlighting the injectability of the biomaterial through a catheter. The biomaterial can maintain its shape upon injection, only becoming liquid after a force is applied. Inset is a zoomed image of the shear-thinning biomaterial extruded from the catheter tip. Credit: Ali Khademhosseini.

The new material can be delivered through a catheter inside the blood vessels to prevent bleeding. It flows through the catheter but once inside the blood vessel it will retain its shape and block it. The gel will then naturally degrade over time.

"This work is an example of how bioengineering can help address the challenges that clinicians and patients face," said Khademhosseini. "Our work thus far has been in the lab, but we are on a translational path to bring this new biomaterial for embolization to the clinic to improve patient care."

Researchers tested the new material in rodents and then pigs because the dimensions of their blood vessels are similar to humans.

“We are aiming to push the clinical application of the material through extensive toxicology studies and subsequent FDA approval pathway,” says Khademhosseini, who hopes to have the material on the market in three to five years.

Featured image courtesy of NIH.