Good news from Phys.org: 3D-printed 'living material' could clean up contaminated water
Researchers at the University of California San Diego have developed a new type of material that could offer a sustainable and eco-friendly solution to clean pollutants from water.
Dubbed an "engineered living material," it is a 3D-printed structure made of a seaweed-based polymer combined with bacteria that have been genetically engineered to produce an enzyme that transforms various organic pollutants into benign molecules. The bacteria were also engineered to self-destruct in the presence of a molecule called theophylline, which is often found in tea and chocolate. This offers a way to eliminate them after they have done their job.
The researchers describe the new decontaminating material in a paper published in Nature Communications.
To create the living material in this study, the researchers used alginate, a natural polymer derived from seaweed, hydrated it to make a gel and mixed it with a type of water-dwelling, photosynthetic bacteria known as cyanobacteria.
The mixture was fed into a 3D printer. After testing various 3D-printed geometries for their material, the researchers found that a grid-like structure was optimal for keeping the bacteria alive. The chosen shape has a high surface area to volume ratio, which places most of the cyanobacteria near the material's surface to access nutrients, gases and light.
The increased surface area also makes the material more effective at decontamination.
As a proof-of-concept experiment, the researchers genetically engineered the cyanobacteria in their material to continually produce a decontaminating enzyme called laccase. Studies have shown that laccase can be used to neutralize a variety of organic pollutants including bisphenol A (BPA), antibiotics, pharmaceutical drugs and dyes.
In this study, the researchers demonstrated that their material can be used to decontaminate the dye-based pollutant indigo carmine, which is a blue dye that is widely used in the textile industry to color denim. In tests, the material decolorized a water solution containing the dye.
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