Microplastics are everywhere.
In our water, our food, even the air we breathe.
The tiny fragments, fibers and films, less than 5 millimeters long, are often made of what’s known as “forever chemicals,” which can take thousands of years to break down.
They’ve been found in human organs — even placentas — as well as plants and animals.
And their effect on human health is still largely unknown, according to Matt Simon, a science journalist at Wired and author of the book A Poison Like No Other: How Microplastics Corrupted Our Planet and Our Bodies. But wait, because there is bad news.
New research suggests that the micro- and nanoplastics (MNPs) present in textiles, car tires, and packaging are polluting the environment and can reach the human brain in a matter of hours.
Micro and nanoplastics are fragments with dimensions less than a millimeter invading all terrestrial and marine environments.
They have become a major global environmental issue in recent decades and, indeed, recent scientific studies have highlighted the presence of these fragments all over the world even in environments that were thought to be unspoiled.
The latest study, conducted on mice, found that nanometer-sized particles could pass through the blood-brain barrier (BBB) within just two hours after oral administration.
The research team performed short-term uptake studies on mice with orally administered polystyrene micro- and nanoparticles of varying sizes. They found that nanometer-sized particles were able to reach the brain, while larger particles were not.
To understand the transport mechanism of these particles, the team conducted coarse-grained molecular dynamics simulations on the interaction of DOPC bilayers with a polystyrene nanoparticle in the presence and absence of various coronae. They discovered that the composition of the biomolecular corona surrounding the plastic particles played a crucial role in their ability to pass through the BBB.
In particular, the team found that cholesterol molecules enhanced the uptake of the contaminants into the membrane of the BBB, while the protein model inhibited it. These opposing effects could explain the passive transport of the particles into the brain.
The study’s findings are concerning, as the accumulation of MNPs in the brain can potentially cause harm to neurological function. The research highlights the importance of properly disposing of plastic waste and reducing our reliance on plastic materials.
The study was conducted by a team of researchers from the Max Planck Institute for Polymer Research, Johannes Gutenberg University Mainz, and the Max Planck Institute for Biophysical Chemistry. Their findings were published in the journal ACS Nano.
The structure and composition of MNPs are closely related to the source material and the most abundant plastic polymers of which they are composed are polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), nylon (PA), cellulose acetate (CA), and thermoplastic polyester (PET).
In the environment, MNPs are easily transported and spread by wind and water currents due to their low density and size; these characteristics and their resistance to biological degradation make them particularly bio-accumulative and resistant to environmental decomposition.