Microscopic plastic particles can penetrate the important protective wall of the brain, according to a study carried out in part in Finland

Very small plastic particles have been found to accumulate in the human body, into the bloodstreamto the lungs, placenta and into breast milk. A recent study shows that so-called nanoplastics can even penetrate the brain’s blood-brain barrier.

The observation is important because the blood-brain barrier is a protective barrier between the bloodstream and the brain. It is formed by the dense inner surface of the capillary blood vessels of the brain, which prevents harmful substances from entering the brain tissue from the blood.

“When we understand how nanoplastics get through the blood-brain barrier, it is also possible to develop ways to prevent possible harm from them”, research director Shark Lehtonen from the University of Eastern Finland says in the bulletin.

The blood-brain barrier was grown in a laboratory, so the experiment was not performed on a human brain. According to Lehtonen, even this laboratory result is worrying. If plastic particles can accumulate in the brain, the question arises whether the accumulation affects brain health in the long term, he summarizes in an email.

For research researchers from the universities of Eastern Finland, Padua and Birmingham and the Helmholtz Center for Environmental Research participated.

Nanoplastics are very small plastic particles, less than a micrometer in diameter, i.e. smaller than a millionth of a meter. The public also talks a lot about microplastics, which are larger.

In general, small plastic particles can be said to be everywhere. They are in the wind, in drinking water, indoor air, in fruits and in steak. Toothpastes, lipsticks, eye shadows and shower gels contain microplastic granules. Particles are released from plastic packaging, worn car tires, fertilizers and street dust.

Previously A US study found plastic particles in 51 brain samples. The samples were obtained during routine autopsies.

Mostly there were 30 times more polyethylene particles in the brain as much as in the liver and kidneys. Plastic bags and packaging materials are made from it, and advanced polyethylene is also used in artificial joints.

The amount of plastics also increased in samples of different years 2016–2024. The assumption was that the plastic particles ended up in the brain because of its high blood flow. The liver and kidneys are perhaps able to take care of the slag more efficiently than the brain.

This research however, has not yet been peer-reviewed.

Fresh The research led by Lehtonen examined the propagation of nanoparticles using a clever method. The researchers followed the migration of polystyrene and polyvinyl chloride (PVC) particles with the help of the element gadolinium added to them.

According to Lehtonen, the particles of these plastics are common in the environment. However, different plastics behave in different ways in the body, and in this study PVC particles penetrated the cells more.

This same method was already shown earlier at the University of Eastern Finland, how plastic is transferred from plants to fish. First, lettuce was grown in soil with nanoplastic particles. Lettuce was fed to the fly larvae and they were fed to the fish. Plastic particles were eventually found in the fish’s body.

It was now discovered that nanoplastic particles in plasma are quickly covered with various biomolecules. The cover formed by them significantly weakens the access of nanoplastics to the cells. It can provide clues to protect the brain.