Nanoplastics penetrate the lungs’ protective barrier: "We have no way to eliminate them," scientists warn

Czech researchers have discovered that nanoplastics can weaken the lungs’ natural defence system, raising fresh concerns about the health risks posed by the tiny particles now found almost everywhere in the environment. Using a special microscope, the scientists were able to observe exactly how nanoplastics behave inside the lungs.

Researchers at the J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences together with colleagues from Poland and Slovenia created an experimental model of a pulmonary alveolus, a tiny air sac in the lungs where oxygen enters the bloodstream. The project focuses on nanoplastics, microscopic plastic particles small enough to enter the human body through the air we breathe, and on how they may damage the delicate protective layer separating air from lung tissue.

“Surfactant is located on the surface of the pulmonary alveoli, which are the final pathway for air into our body. Air penetrates through the surfactant, and conversely, substances that we want to excrete pass back through it and are then breathed out,” explains Lukasz Cwiklik, head of the research team.

But together with air, we also inhale impurities, including those on the nanoscale.

“A lot of nanoplastics are created in our homes. These are not plastics that occur outdoors, but plastics that form in enclosed rooms without us realising it. Their sources include carpets, dishes and household equipment,” says Cwiklik.

Scientists wanted to find out how surfactant, the lungs’ border guard, copes with particles of artificial material a thousand times thinner than a human hair. They therefore obtained samples of polystyrene nanoparticles of precise sizes.

“At the Jagiellonian University in Kraków, they are able to create nanoparticles of various sizes using a grinder. The grinder imitates processes that normally happen at home, for example when we walk on a synthetic carpet,” explains Cwiklik.

Border control

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Experiments showed that plastic nanoparticles can become embedded in fatty, or lipid, structures within the surfactant, which allows them to pass through the lungs’ border control and into the interior of the organism.

“When we breathe, lipids move back and forth, and when a particle that likes lipids is embedded there, it is also able to travel further into the lipid structures beneath the surfactant. Because they are so small, we have no way to eliminate them,” adds Cwiklik.

Plastic nanoparticles, however, cannot simply be seen under a microscope. Scientists observe them indirectly — when they penetrate the surfactant, the surface tension changes and the sample bends light differently. This can be detected using a special instrument.

Scientists are now interested in how the human body could defend itself against the penetration of nanoplastics. After all, they cannot be removed from the air, and more and more particles are constantly being worn off from the objects around us. Besides the lungs, they also enter our eyes.