Injectable synthetic blood clots stop internal bleeding to save lives


Scientists at MIT have developed a synthetic system that can stem internal bleeding, to help more people survive long enough to reach a hospital after a traumatic injury. Two components come together at the wound to form a clot, without doing so elsewhere in the body where it might be dangerous.

Traumatic events like car crashes can cause internal bleeding, and if patients don’t reach a hospital in time they can be fatal. Finding ways to stop the bleeding can extend that window, potentially saving lives.

The MIT team has now developed a synthetic system that could be injected by first responders to stem internal bleeding. It does so using nanoparticles and polymers that work to boost the formation of natural blood clots.

Normally, cells called platelets are attracted to the site of a wound, where they trigger a cascade of processes that form a sticky clot. A protein called fibrinogen is also important for maintaining the structure of these clots.

The new system is made up of two major components – nanoparticles that recruit platelets, and a polymer that mimics fibrinogen. The nanoparticles are made of a biocompatible material called PEG-PLGA, and have a peptide that helps them bind to activated platelets. This means that they accumulate where there are higher concentrations of platelets, such as wounds, and work to draw even more to the area. The size of these nanoparticles has also been optimized to be between 140 and 220 nanometers, which keeps them from building up in organs like the lungs where clots can be dangerous.

Importantly, the team also created a crosslinker system, with a chemical group on the nanoparticles that binds to a tag on the fibrinogen-mimicking protein. This helps the two components in the synthetic clotting system find each other at the site of a wound and plug it up more efficiently.

“The idea is that with both of these components circulating inside the bloodstream, if there is a wound site, the targeting component will start accumulating at the wound site and also bind the crosslinker,” said Celestine Hong, lead author of the study. “When both components are at high concentration, you get more cross-linking, and they begin forming that glue and helping the clotting process.”

The team tested the system in mouse models of internal bleeding, and found that the system with two components worked about twice as well as a version containing just the platelet-recruiting nanoparticles. No significant immune reaction was seen either.

Of course, animal studies don’t always translate to humans, so there’s still plenty of work left to do before this could be used in the clinic, if ever. But it’s an intriguing technique that could one day save lives in emergency rooms or the battlefield.

New Atlas, 26 April 2023