The identical distinctive construction that makes plastic so versatile additionally makes it vulnerable 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 intrude with mobile operate and even alter DNA. Researchers have discovered these particles in almost each atmosphere 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 vulnerable 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 have a look at a bit of plastic by way of a robust microscope, you’ll see alternating layers of exhausting materials and mushy materials. Within the exhausting layers, plastic molecules are rigidly organized in sturdy crystal buildings. Within the mushy layers, the molecules lack construction and type a mushy, amorphous mass.
When hundreds of those layers are stacked collectively, they create a fabric that’s light-weight, sturdy, and very versatile. Importantly these supplies derive their distinctive properties by way of the connectivity between the mushy and exhausting phases.
In a paper printed March 28 in Nature Communications, the researchers clarify how nanoplastics type. They found that the method begins within the mushy layers, which develop weaker over time on account of environmental degradation and may break off even when the plastic is just not underneath stress. By themselves, these mushy items break down rapidly within the atmosphere. Issues come up when the failure of a mushy layer permits exhausting layers to interrupt off. These crystalline fragments are the nano- and microplastics that may persist within the atmosphere for hundreds of years and trigger vital harm in dwelling 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’s loads of anecdotal proof of nanoplastics — folks have discovered them far and wide and seen them type — however nobody had decided the mechanisms behind how they type.
What did you uncover?
75% of all plastic used has form of a brick-and-mortar construction. It’s made from actually skinny alternating layers: exhausting, mushy, exhausting, mushy, and so forth. We’ve identified for the reason that Nineteen Fifties that the mushy stuff is holding the exhausting stuff collectively.
What we present within the new research is how simply these mushy connectors break even underneath quiescent circumstances comparable to in a landfill. As soon as that layer fails, the exhausting segments have nowhere to go — they scatter into the atmosphere.
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’ll begin messing with DNA. Nano- and microplastics, which appear to have comparable shapes and sizes to asbestos, increase the potential that they might trigger most cancers, coronary heart illness/stroke, and different ailments.
Is there an engineering resolution to handle this downside?
Our outcomes recommend that engineering the structure of the mushy 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 for those who simply throw plastic into the atmosphere, it creates micro- and nanoplastics that seem like they will trigger well being issues.
If you consider it that approach, if it’s important to select between the well being issues that might 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 Ok. Lee, Linda S. Schadler, Alejandro J. Müller, Shelby Watson-Sanders, Mark Dadmun, Guruswamy Kumaraswamy and Sanat Ok. 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.