We use many plastic products just once, but the material sticks around for years. So researchers looked for a way to fix that with living plastics that self-destruct on command.
Zhuojun Dai, a corresponding author on the study in ACS Applied Polymer Materials, said, “The realization that traditional plastics persist for centuries, while many applications, like packaging, are short-lived, led us to ask: Could we build degradation directly into the material’s life cycle?”
How the Technology Works
Many microbes break long polymer chains down into smaller pieces using enzymes. The team wanted to improve how well this happens. Instead of using one enzyme, Dai and his team, including Jin Geng and Dianpeng Qi, engineered the bacteria Bacillus subtilis.
This bacteria produces two polymer-degrading enzymes. One enzyme acts like a random chopper that cuts long chains into smaller pieces. The second enzyme slowly chews those pieces from each end.
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“By embedding these microbes, plastics could effectively ‘come alive’ and self-destruct on command, turning durability from a problem into a programmable feature,” Dai explained.
To test this, the team mixed dormant spores of the bacteria with polycaprolactone, a polymer used in 3D printing and some surgical sutures. The resulting plastic had the same mechanical properties as the plain material.
A New Way to Tackle Plastic Waste
When they added a nutrient broth at 122 degrees Fahrenheit (50 degrees Celsius), the spores activated and broke the plastic all the way down to its base building blocks in just six days. The team’s process was so efficient that it did not leave behind any microplastic particles.
To test this in a real-world example, the researchers made a wearable plastic electrode out of their living plastic. It performed exactly as expected and degraded completely within two weeks.
In the future, the team hopes to create a trigger for the spores in water, where much of our plastic pollution ends up. And while this test only looked at one type of polymer, this same approach could eventually work for other plastics, including the ones we use in single-use packaging every day.
