While external bleeding can be stopped by a variety of methods, internal bleeding caused by injuries to organs can only be stopped with surgery. Whether internal injuries are sustained on a highway or a battlefield, a life can often be saved or lost depending on how fast internal bleeding can be stopped. Erin B. Lavik, Sc.D. and a team of researchers are working on developing nanoparticles that can assist blood clotting at the injured site (specially made nanoparticles automatically gather at the destined spot). Tests on the technique have been performed in vivo and in test tubes.
Lavik notes that the particles will make the biggest difference when uncontrolled internal bleeding occurs. The particles can reduce bleeding time by half and decrease total blood loss when compared to untreated injuries.
Doctors have a few choices for treating internal bleeding, although trauma remains the top cause of death in children and younger adults. The nanoparticles bind to activated platelets and helps them join to form blood clots. Activated platelets are characterized by glycoprotein and the particles are coated with molecules that sticks to the protein.
In initial studies done on rodents, the particles helped and prevented them of bleeding out due to brain and spinal injury. The nanoparticles were administered intravenously. Lavik does however admit that this does not necessarily mean that the treatment would be effective on humans. If nanoparticles are administered and this triggers an immune response, it would be an indication that the body is mounting a defense against the nanoparticle and that side effects are likely to occur. So the next step was to use a pig’s blood for testing. After adding nanoparticles to the pig’s blood, the team checked for an increase in complement, which is a key indicator of immune response activation. Complement was indeed detected, so the team had to find a way around this problem.
Different batches of particles with different charges were then manufactured and these were tested. Particles with a neutral charge were shown to be the most effective, but this did bring about another challenge. As the particles don’t have repulsive charge interactions with each other, they aggregated before even being injected. The team changed the solution in which the particles were stored by adding a slippery polymer to it. The polymer prevents the nanoparticles from sticking to each other.
Nanoparticles that remain stable at up to 122 degrees Fahrenheit (50 degrees Celsius) have also been designed. These can now be stored when on a scorching battlefield or in a hot ambulance.
Further studies are needed to determine whether the nanoparticles will stick to activated complement in human blood or not. Critical safety checks also need to be done to make sure the nanoparticles don’t cause non-specific clotting, which, if it happens, could cause a stroke. At least another five to ten years of study will be needed before a useful clinical product can be released to the market.
The researchers presented their work at the 252nd National Meeting & Exposition of the American Chemical Society (ACS).