Nanoparticles Can Save Lives By Controlling Serious Blood Loss

Highlights

• Blood loss is the main cause of death in most trauma cases.
• External bleeding can be controlled, but internal hemorrhage can only be controlled by surgery.
• Role of nanoparticles in speeding up clotting and controlling blood loss was studied.
• Nanoparticles have the potential to reduce blood loss and save life.

Nanoparticles are particles that measure less than 100 nm across one dimension at least. Due to their small size, they attain certain specific physicochemical properties such as a high surface area to volume ratio. This property makes them useful in several fields including medicine.

Blood Clotting Explained Simply

In any blood vessel injury, the body controls bleeding by a complex interplay between various constituents of the vessel wall lining (endothelium) and platelets followed by activation of clotting factors.

In most minor injuries, the normal physiological mechanisms mentioned above are sufficient to control blood loss and prevent serious hemorrhage.

With larger external injuries, the wound may have to be sutured to control severe blood loss.

In trauma and accident cases, the issue is complicated further by serious injuries both externally and internally. Internal injuries and hemorrhage have to be treated only by surgery at present.

How do Nanoparticle Work to Stop Bleeding

In order to address the need for controlling bleeding related deaths, especially in trauma cases, researcher Erin B. Lavik and her team have developed a nanoparticle that helps in quick clotting.

This nanoparticle is capable of binding with activated platelets at the site of blood vessel injury. It acts as a bridge connecting neighbouring platelets and helps to form clots, thereby controlling the bleeding.

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To ensure that there is no non-specific binding, this nanoparticle is coated with a substance that can only stick to a glycoprotein found on the surface of platelets.

Studies in Rodents

Initial studies conducted in rodents showed that nanoparticles administered intravenously could prevent them from bleeding to death due to brain or spinal injuries. However Lavik admits that further research and studies are necessary to prove its efficacy in humans.

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Tweaking the Nanoparticle for Testing in Humans

In order that the nanoparticle be safe for human use, it should not activate the immune system and trigger an immune response which would be problematic.

To test whether the immune system is activated, nanoparticles were added to pig’s blood and levels of complement (key in immune responses) were tested. Unfortunately they were found to be high.

To try and reduce the immune response effect, Lavik and her team created nanoparticles with different charges and found that neutrally charged nanoparticles evoked the least immune response.

However neutral particles had a tendency to clump even before they were injected. This was overcome by adding a slippery polymer to the nanoparticle storage solution that prevented their clumping.

Other Modifications

Also suitable modifications were made to ensure that the nanoparticles remained stable at high temperatures of 50^oC (122^oF) and still be effective, such as in the hot and sweltering conditions that could be expected in a battlefield.

Future Studies Planned on the Nanoparticles

Studies on human blood are being planned to check for immune response and complement activation.

Additional safety measures are being included to ensure that the particle does not cause non-specific clotting, leading to stroke.

If the study progresses well, it is hoped that a useful clinical product may be available within the next 5 – 10 years.

References:

1. Nanoparticles that speed blood clotting may someday save lives - (http://phys.org/news/2016-08-nanoparticles-blood-clotting.html)

Source-Medindia