Plastics that melt in the ocean offer new hope for cleaner seas
One day we can say goodbye to microplastics.
Plastic has become a permanent fixture in modern life—and that’s exactly the problem. Designed for convenience, it clogs oceans, chokes marine life, and lingers in ecosystems for centuries. Even when it breaks down, it often becomes microplastics that infiltrate food chains. Despite efforts like recycling, bans, and biodegradable alternatives, microplastic pollution remains an overwhelming challenge.
But scientists may have discovered a promising new approach: a type of plastic that doesn’t stick around. A study published in Science introduces “supramolecular plastics,” materials that dissolve safely into saltwater. These plastics are strong, versatile, and designed to disappear when exposed to the ocean. The material could help address one of the world’s most persistent environmental problems.
“With this new material, we have created a new family of plastics that are strong, stable, recyclable, can serve multiple functions, and importantly, do not generate microplastics,” said Takuzo Aida at the RIKEN Center for Emergent Matter Science.
Make biodegradable plastic
This new plastic is made using two key components. The first, sodium hexametaphosphate, is commonly used in food products and cleaning agents. The second, guanidinium sulfate, is a salt-based compound. When these two are mixed in water, they create a dense, interlinked network held together by molecular forces called “salt bridges.” Once this network forms, it can be dried and shaped into plastic films, molds, or even complex 3D-printed objects.
These plastics are built from two surprisingly common components: sodium hexametaphosphate, found in food and detergents, and guanidinium sulfate, a salt-based compound. When dissolved in water, they form a dense molecular network held together by salt bridges. Once dried, the material can be molded into films, containers, or even 3D-printed shapes.
Here’s the magic: in saltwater, those molecular bonds are disrupted. The network disintegrates back into its harmless building blocks—substances that marine bacteria can digest. In tests, thin films dissolved in hours; thicker pieces in just a few days.
Unlike many biodegradable plastics, which only break apart under industrial conditions or after lengthy exposure to heat, this plastic responds to the very environment it is most likely to end up in—the ocean. Even outside the sea, it is designed to decompose gradually, guaranteeing it doesn’t contribute to long-term waste. When buried in soil, for example, it naturally breaks down into organic compounds, unlike conventional plastics.
Also, the new material is non-toxic and non-flammable—meaning no CO2 emissions—and can be reshaped at temperatures above 120°C like other thermoplastics.
The plastics aren’t just eco-friendly; they’re also strong and versatile.
“While the reversable nature of the bonds in supramolecular plastics have been thought to make them weak and unstable, our new materials are just the opposite,” Aida said.
Tests showed that it performs as well as many traditional plastics, with the durability to hold up under heat and pressure. Its ability to be reused or recycled also sets it apart. The researchers demonstrated a process to dissolve and recover its key components, which can be used to create new plastics. This approach makes the material a candidate for supporting a circular economy, where waste is minimized, and materials are continuously repurposed.
The potential for this type of plastic is massive. Aside from 3D printing and medial materials, everyday items like food packaging and single-use containers, not to mention the biggie—plastic shopping bags—could be made from it.
While the science behind supramolecular plastics is innovative to say the least, bringing this material into widespread use will require time and investment. Manufacturing systems must be adapted to produce it commercially, and industries that rely on traditional plastics will need to see its value. Costs and durability in extreme conditions will need further testing, and policymakers must step in to encourage its adoption.
Still, the discovery represents an important shift in how plastics are imagined and designed. By creating materials useful for a finite time and then disappearing without harm, scientists are rethinking the very nature of waste.
Jordan Strickler
A space nerd and self-described grammar freak (all his Twitter posts are complete sentences), he loves learning about the unknown and figures that if he isn’t smart enough to send satellites to space, he can at least write about it. Twitter: @JordanS1981
Scientists urge plastic limit for lateral flow tests
A new study published in the Bulletin of the World Health Organisation (WHO) calls for urgent action to limit plastic waste in these essential diagnostic tools
Lateral flow tests have transformed global healthcare by enabling rapid disease detection and improving access to medical diagnostics.
However, their widespread, single-use design is creating an environmental crisis.
A new study published in the Bulletin of the World Health Organisation (WHO) calls for urgent action to limit plastic waste in these essential diagnostic tools.
Researchers from Heriot-Watt University and the University of Edinburgh propose limiting how much plastic is used in test kits to curb unnecessary plastic waste.
Their study, which analysed 21 different COVID-19 kits, highlights the significant variation in plastic usage and identifies opportunities for manufacturers to reduce material consumption without compromising effectiveness.
The weight of plastic varied from six grams to almost 40 grams per individual test.
Call to include maximum limits in test specifications
Companies or organisations that want to create lateral flow and similar tests use target product profiles.
These specify design elements that manufacturers must meet, whether cost, weight or size.
Professor Maïwenn Kersaudy-Kerhoas, co-lead of Heriot-Watt’s Global Research Institute in Health & Care Technologies, said: “We have found few target product profiles that mention the environmental impact of tests, and none provide quantitative measures
“We want these profiles to include a limit of four grams of plastic usage in the lateral flow tests cassettes, for example.
“Our study showed that was the average weight of plastic in test cassettes, so it’s achievable.”
“We hope this will be adopted as policy and an industry standard.”
Professor Alice Street, an expert in anthropology and health at the University of Edinburgh, added: “Improving access to essential medical testing should not come at the expense of environmental sustainability. Our findings show that reducing plastic waste in test kits is both feasible and necessary.”
Growing environmental impact
More than two billion lateral flow tests are produced annually.
In 2023 alone, the Global Fund to Fight AIDS, Tuberculosis, and Malaria invested in 53 million HIV tests and 321 million malaria tests.
While these tests expand access to healthcare, their plastic waste burdens waste management systems worldwide. In regions that lack proper disposal facilities, used test cassettes often end up in landfills and waterways or are openly burned, releasing pollutants. Even in developed nations, recycling these materials remains rare.
Pathways to greener diagnostics
The study suggests setting plastic usage limits in test kit manufacturing.
Professor Kersaudy-Kerhoas said: “The convenience of lateral flow tests is undeniable, but we must acknowledge the long-term environmental consequences of single-use diagnostics.
“If we do not act now, we risk creating an environmental crisis that undermines the health benefits these tests provide.”
The researchers urge policymakers, manufacturers, and global health organisations, including WHO, FIND, and PATH, to integrate environmental criteria into regulatory guidance and procurement processes.
By establishing sustainability benchmarks, they believe the industry can continue to provide essential diagnostics while reducing plastic waste.
Next steps
The Heriot-Watt team is calling for governments and health organisations to refine environmental standards in diagnostic manufacturing and implement policies that reduce reliance on virgin petrochemical plastics.
The full study, Mass of Components and Material Distribution in Lateral Flow Assay Kits, is available in the Bulletin of the World Health Organization (2025;103).
The Global Research Institute in Health and Care Technologies works closely with industry and sector partners to deliver innovative, sustainable and use-inspired solutions to global health challenges in a spirit of co-creation. It applies Heriot-Watt University’s world-leading research and engineering capabilities to tackle challenges in an ever-changing world.
Anyone interested in collaborating with the new Global Research Institute in Health and Care Technologies at Heriot-Watt University should contact the Global Research Innovation and Design team at GRID@hw.ac.uk.
Journal
Bulletin of the World Health Organization
No comments:
Post a Comment