Researchers suggests that an injection of nanoparticles may be able to help fight the immune system when it goes haywire, researchers at the University of Michigan have shown. The nanoparticles divert immune cells that cause inflammation away from an injury site. Inflammation is a double-edged sword. When it works, it helps the body heal and fights off infections.

But sometimes, the immune system overreacts. An acute lung injury, sustained by inhaling smoke, for instance, can lead to runaway fluid production that essentially drowns a person. Now, experiments in mice suggest that simple plastic nanoparticles, delivered by IV, may be able to keep a type of immune cell called a neutrophil, too busy to cause inflammation. Other diseases in which neutrophils because excessive inflammation include sepsis and the hardening of the arteries, or atherosclerosis.

Omolola Eniola-Adefeso said, "Neutrophils are the first line of defense. They are the most active and the most optimized to mount an inflammatory response," said Omolola Eniola-Adefeso. "They're the underdogs of white blood cells, and we're seeing that maybe we need to pay more attention to them." She didn't start out looking to redirect the immune system with nanoparticles.

Rather, her work has been exploring the dynamics within blood vessels that help or hurt the ability of nanoparticles to deliver drugs to the blood vessel wall and beyond. In experiments, her students ran blood through artificial blood vessels channels etched into a chip and lined with the same kind of cells that line blood vessel walls.

At first, they saw only that the neutrophils were banishing their plastic particles, which were designed to attach to the blood vessel wall. This was a problem because if the particles couldn't bind, they couldn't deliver drugs to diseased tissue. The neutrophil concentration was like the concentration found in the blood of uninjured mice. Instead, the neutrophils were taking the particles to the liver, where they could be removed from circulation.

Her group will also continue troubleshooting nanoparticles as vehicles for targeted drug delivery. One way to keep the neutrophils away is to coat the particles with so-called nonfouling materials that are resistant to picking up proteins from the blood. Because the chemicals that the team uses to attach the nanoparticles. It is attached to the blood vessel walls are the same as those used by the neutrophils themselves, a coating that combines nonfouling materials with the targeting chemicals will throw most white blood cells off the scent.

Otherwise, few other groups have been taking the membranes from the cells, which naturally travel to the targeted tissue. In occurrence, the neutrophils that attach to the blood vessel wall and putting nanoparticles inside them. Like the alien in human skin from the film "Men in Black."