Nanoparticles Minimize Brain Injury from Trauma

Researchers at Rice University and Baylor College of Medicine have found that nanoparticles can reduce brain damage that occurs during treatment of even relatively mild trauma. Infusion of clusters of chemically linked carbon nanotubes called PEG-HCC rapidly and effectively neutralize free radicals produced by cells at the injury site.

Cells at the site of a brain trauma, even a relatively mild one, release large amounts of superoxide, a radical oxygen compound that is part of the body's defense to prevent infection. Under normal conditions, this toxin is kept at reasonable levels by the superoxide dismutase enzyme which neutralizes it. However, on occurrence of an injury, much more superoxide is produced which overwhelms the dismutase's ability to clear it. This is where the nanoparticles come in.

The PEG-HCC nanoparticles can immediately and completely neutralize large amounts of superoxide. This is because each nanoparticle can combine with and neutralize hundreds of thousands of superoxide molecules. In contrast, superoxide dismutase neutralizes one molecule at a time. Co-author James Tour noted in the press release that "it's really radical annihilation. There's no such mechanism in biology."

While excessive superoxide generates damaging toxic free-radical chemicals, the main problem with superoxide is that it is also disrupts circulation regulation. It prevents blood vessels from dilating and constricting appropriately which can produce brain damage beyond the point of injury.

The treatment, of course, cannot be applied during the initial burst of superoxide at the time of injury. However, a second burst of free radicals occurs post-injury during resuscitation when medical experts are trying to restore blood pressure. It is during this 'reboot' of the blood flow that the nanoparticle treatment is effective.

The PEG-HCC nanoparticles have other biological applications. It was actually while they were being developed and tested for delivery of chemotherapeutics such as paxital and cetuximab to treat cancer, that the antioxidant properties were noticed. While testing for liver toxicity, researchers noticed that the PEG-HCC was enabling the liver cells to survive longer than normal. It wasn't just non-toxic but it was actually protective.