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Nanoparticles designed to distract the body’s immune system can be an effective tool to help target inflammation.

Researchers from the University of Michigan have found that injecting nanoparticles helps fight the immune system by diverting immune cells that cause inflammation away from an injury site.

Inflammation helps the body heal and fight off infections, but also can cause the immune system to overreact at times.

The researchers found in mice that simple plastic nanoparticles—delivered by IV—might be able to keep the neutrophil immune cells known to cause excessive inflammation “too busy” to cause inflammation.

“Neutrophils are the first line of defense,” Omolola Eniola-Adefeso, a professor of chemical engineering and biomedical engineering at Michigan, who led the research, said in a statement. “They are the most active and the most optimized to mount an inflammatory response.

“They're the underdogs of white blood cells and we're seeing that maybe we need to pay more attention to them.”

The researchers 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 found that only the neutrophils were banishing their plastic particles—that were designed to attach to the blood vessel wall, showing that the particles couldn’t bind or deliver drugs to diseased tissue.

However, after examining microscope video footage, the researchers realized that the neutrophils also vanished, as they weren’t binding to the blood vessel wall either.

“The 'oh my God' of horror about our particle turned into an excitement over these particles doing something to cells that had not previously been explored,” Eniola-Adefeso said. “These cool interactions between cells and particles got in the way of either one being able to do what they wanted to do.”

The research team then designed an experiment injuring part of the blood vessel wall in the microfluidic chips and confirmed that the neutrophils were redirecting their attention from creating inflammation at the injury site to carting the foreign particles away.

The chemicals used to attach the nanoparticles to the blood vessel walls are the same as those used by the neutrophils themselves, meaning the researchers must now find a coating that combines nonfouling materials with the targeting chemicals that will throw most white blood cells off the scent.

“To date, we've tried many nonfouling materials. But in the end, they foul because nature is very sophisticated,” Eniola-Adefeso said. 

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