The identical distinctive construction that makes plastic so versatile additionally makes it inclined to breaking down into dangerous micro- and nanoscale particles.
The world is saturated with trillions of microscopic and nanoscopic plastic particles, some smaller than a virus, making them sufficiently small to intervene with mobile operate and even alter DNA. Researchers have discovered these particles in almost each surroundings they’ve studied, from Antarctic snow to human blood.
In a brand new research, scientists have mapped out the molecular mechanisms behind the widespread formation of those tiny plastic fragments. Since plastic first entered the market 75 years in the past, its use has develop into almost common—and so has the presence of nanoplastics.
The identical properties that make plastic sturdy and versatile additionally make it inclined to breaking down into nanoscale items. This breakdown is very frequent within the 75-80% of plastics categorized as semicrystalline polymers. The analysis was led by Sanat Kumar, Michael Bykhovsky, and Charo Gonzalez-Bykhovsky, professors of Chemical Engineering at Columbia Engineering.
In the event you take a look at a chunk of plastic by way of a strong microscope, you’ll see alternating layers of arduous materials and delicate materials. Within the arduous layers, plastic molecules are rigidly organized in robust crystal buildings. Within the delicate layers, the molecules lack construction and type a delicate, amorphous mass.
When 1000’s of those layers are stacked collectively, they create a fabric that’s light-weight, sturdy, and intensely versatile. Importantly these supplies derive their distinctive properties by way of the connectivity between the delicate and arduous phases.
In a paper printed March 28 in Nature Communications, the researchers clarify how nanoplastics type. They found that the method begins within the delicate layers, which develop weaker over time as a consequence of environmental degradation and may break off even when the plastic shouldn’t be beneath stress. By themselves, these delicate items break down shortly within the surroundings. Issues come up when the failure of a delicate layer permits arduous layers to interrupt off. These crystalline fragments are the nano- and microplastics that may persist within the surroundings for hundreds of years and trigger vital harm in residing issues, together with people.
We sat down with Kumar to be taught extra about this work.
How does this paper contribute to our understanding of nanoplastics?
There may be lots of anecdotal proof of nanoplastics — folks have discovered them everywhere and seen them type — however nobody had decided the mechanisms behind how they type.
What did you uncover?
75% of all plastic used has kind of a brick-and-mortar construction. It’s made from actually skinny alternating layers: arduous, delicate, arduous, delicate, and so forth. We’ve identified for the reason that Nineteen Fifties that the delicate stuff is holding the arduous stuff collectively.
What we present within the new research is how simply these delicate connectors break even beneath quiescent circumstances comparable to in a landfill. As soon as that layer fails, the arduous segments have nowhere to go — they scatter into the surroundings.
Why is that an issue?
These items float round, and a few find yourself in human our bodies. The smallest items move by way of cells and into the nucleus, the place they will begin messing with DNA. Nano- and microplastics, which appear to have related dimensions and shapes to asbestos, elevate the potential that they might trigger most cancers, coronary heart illness/stroke, and different ailments.
Is there an engineering resolution to deal with this drawback?
Our outcomes counsel that engineering the structure of the delicate layers to be extra resilient would lower the quantity of crystalline fragments that break off.
Clearly, focus must be positioned on this level to scale back the quantity of micro and nano plastics created by regular polymer degradation.
How can higher understanding nanoplastics enhance human well being?
Solely 2% of plastics are recycled, principally as a result of it’s too costly. However if you happen to simply throw plastic into the surroundings, it creates micro- and nanoplastics that seem like they’ll trigger well being issues.
If you concentrate on it that manner, if it’s a must to select between the well being issues that may very well be created by the nanoplastics vs. the price of recycling, then possibly it’s truly cheaper to recycle.
Reference: “Mechanism of quiescent nanoplastic formation from semicrystalline polymers” by Nicholas F. Mendez, Vivek Sharma, Michele Valsecchi, Vighnesh Pai, Johnny Okay. Lee, Linda S. Schadler, Alejandro J. Müller, Shelby Watson-Sanders, Mark Dadmun, Guruswamy Kumaraswamy and Sanat Okay. Kumar, 28 March 2025, Nature Communications.
DOI: 10.1038/s41467-025-58233-3
The research was funded by the U.S. Nationwide Science Basis and the Basque Authorities.
