Plastic waste persists in nature for centuries, even though the items themselves are used for only minutes. In the quest for a solution, scientists are developing “living” polymers that contain dormant microorganisms, which begin breaking down the material upon receiving a specific signal.
Chinese researchers have introduced a self-destructing “living” plastic in the journal ACS Applied Polymer Materials. Genetically modified bacteria embedded within it completely decompose the material in six days, without generating microplastics—offering a potentially new approach to tackling single-use waste.
The study utilized the bacterium Bacillus subtilis, which naturally produces an enzyme that breaks down polymer chains. The scientists engineered the bacterium to generate two different enzymes that work together for more efficient degradation.
The first enzyme cleaves long polymer chains at random points, forming short fragments. The second enzyme then breaks these fragments down into individual monomers—the fundamental building blocks.
Spores of the modified B. subtilis were incorporated into polycaprolactone, a polymer used in 3D printing and surgical sutures. The resulting “living” plastic exhibited mechanical properties similar to those of standard polycaprolactone films and remained robust under normal conditions.
To activate the bacteria, a nutrient broth heated to 50 °C was applied to the film. The spores awakened and began producing both enzymes. Due to the sequential action of the enzymes, the material did not merely disintegrate into tiny pieces; instead, it fully decomposed into monomers over six days, preventing the formation of microplastics.
“Embedding these microbes allowed the plastic to essentially ‘come alive’ and self-destruct on command, turning durability from a drawback into a programmable feature,” explained co-developer Zhuojun Dai.
To demonstrate a practical application, the researchers created a wearable plastic electrode from the “living” material. The device functioned properly and, after activation, fully degraded within two weeks.
“Living” plastic can be used in products that need to be strong for a limited time but should not persist after disposal, the authors note.
In the future, the team plans to develop a method for activating the spores in water, where a large amount of plastic pollution accumulates.
Although the experiments were conducted with a single polymer, the scientists believe the strategy can be adapted to other materials, including plastics used for disposable items.
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