Major internal bleeding is a very serious condition that requires immediate attention, and it's difficult to treat non-surgically. Scientists from Russia's ITMO University are working on an effective means of doing so, however, in the form of injectable magnetic nanoparticles.

One of the challenges in developing medication for the treatment of internal bleeding is that you don't want it to cause blood clots throughout the vascular system – only at the bleeding site.

Led by Vladimir Vinogradov, the research team has attempted to address this concern by creating nanoparticles consisting of an enzyme known as thrombin, wrapped within a porous matrix composed of the mineral magnetite – thrombin triggers the formation of blood clots, when it interacts with a naturally-occurring protein called fibrinogen.

When tested in a model blood stream set up in a lab, the nanoparticles didn't cause clots as long as they were evenly distributed throughout the blood vessels – in fact, the thrombin in them was less active that it would be if free of the magnetite matrix.

When a magnet was used to concentrate them at a simulated vascular injury site, though, and a shot of fibrinogen was added to give the thrombin an activity boost, they caused a clot to form 6.5 times faster than would otherwise have been the case. This in turn resulted in 15 times less blood being lost.

The scientists now hope that a drug containing the nanoparticles could ultimately be injected into patients' bodies, with the particles then guided into place by externally-applied magnetic fields.

"It is important to keep their size down to 200 nanometers; otherwise they will not be suitable for injection," Vinogradov says of the nanoparticles. "In addition, mild synthesis conditions are required so that the thrombin molecule does not break down and lose its activity completely. Finally, we could only use biocompatible components. We checked the toxicity of our particles with human cells and made sure they are completely safe even during prolonged exposure."

Plans call for animal trials to take place next. A paper on the research was recently published in the journal Scientific Reports.