Researchers at the University of California at San Diego have developed a new type of material that could offer a sustainable and eco-friendly solution for keeping water free of pollutants.
Dubbed “engineered living material,” it is a 3D-printed structure made of a seaweed-based polymer combined with genetically modified bacteria to produce an enzyme that converts various organic pollutants into safe molecules. The bacteria were also designed to self-destruct in the presence of a molecule called theophylline, often found in tea and chocolate. This allows you to eliminate them once they’ve done their job.
The researchers describe the new decontamination material in a paper published in the journal Nature Communications.
“What’s innovative is to combine a polymeric material with a biological system to create a living material that can function and respond to stimuli in ways that conventional synthetic materials cannot,” said John Pokorski, professor of geoengineering at the University of California, San. Diego is a co-author of the study. supervised the work.
The work was the result of a collaboration between engineers, materials scientists and biologists at UC San Diego’s Center for Materials Research and Materials Engineering (MRSEC). Leaders of the multidisciplinary group include molecular biology professors Susan Golden and James Golden and geoengineering professor Shaochen Chen.
“This collaboration has allowed us to apply our knowledge of cyanobacterial genetics and physiology to the creation of living material,” said Susan Golden, faculty member in the School of Biological Sciences. “We can now be creative in designing new functions of cyanobacteria to produce more useful products.”
To create the living material in this study, the researchers used alginate, a natural polymer derived from seaweed, moistened it to form a gel, and mixed it with a type of aquatic photosynthetic bacteria known as cyanobacteria.
The mixture was fed into a 3D printer. After testing different geometric shapes of the 3D-printed material, the researchers found that the lattice structure was best suited to support bacterial life. The shape chosen has a high surface area to volume ratio, allowing most cyanobacteria to settle close to the surface of the material, providing access to nutrients, gases and light.
The increased surface area makes the material more effective at decontamination.
In a proof-of-concept experiment, the researchers genetically modified the cyanobacteria in their material to continuously produce a disinfecting enzyme called laccase. Studies have shown that laccase can be used to neutralize a variety of organic pollutants, including bisphenol A (BPA), antibiotics, pharmaceuticals, and dyes.
In this study, the researchers demonstrated that their material could be used to purify a contaminant based on indigo carmine dye, a blue dye commonly used in the textile industry to dye jeans. During the tests, the material was discolored due to an aqueous solution containing dye.
Researchers have also developed a way to kill cyanobacteria after removing contaminants. They genetically modified the bacteria to respond to a molecule called theophylline. The molecule causes the bacteria to produce a protein that destroys their cells.
“The living material can act on the contaminant of interest, and then you can add a small molecule to kill the bacteria,” Pokorsky said. said. “In this way, we can remove concerns about the persistence of genetically modified bacteria in the environment.”
The researchers state that the preferred solution is to kill the bacteria without adding chemicals. This will be one of the future directions of this research.
“Our goal is to create materials that respond to stimuli already present in the environment,” said Pokorsky.
“We are inspired by the possibilities this work opens up, by the exciting new materials we can create. This is the type of research that could result in researchers with interdisciplinary backgrounds in materials science and biological sciences joining forces. All of this is made possible by our interdisciplinary research team at UC San Diego’s MRSEC. ” Source
Source: Port Altele
