Inventions that deal with water purification and sterilization issues are usually exclusively for researchers specializing in materials science, who are most interested in inventing new materials that perform these tasks, but surprisingly, among the list of researchers in the latest study in this field that came out of the University of California, San Diego, and published in the journal "Nature Communication", are scientists specializing in genetics, due to the nature of the new material invented by the researchers.
Polymer with biological system
The researchers called their new material "living matter", which is a three-dimensional printed structure made of a polymer extracted from seaweed with bacteria genetically engineered to produce an enzyme that converts various organic pollutants into benign molecules, and the bacteria are also designed to self-destruct in the presence of a molecule called "theophylline", which is often found in tea and chocolate, and this provides a way to eliminate them after they have done their job.
John Pokorsky, a professor of nanoengineering at the University of California and co-author of the study, said in a September 5 news release on the university's website, "What's new is that the polymer material is paired with a biological system to create a living material that can work and respond to stimuli in ways that ordinary synthetic materials cannot, so engineers, materials scientists and biologists at the UCLA Materials Research Science and Engineering Center have collaborated on this work."
The collaboration allowed biologists to apply their knowledge of genetics and cyanobacterial physiology to create living matter, explains Susan Golden, a faculty member in the School of Biological Sciences and co-author of the study in a press release published by the university's website.
How was it manufactured?
To create the living matter in this study, the researchers used alginate, a natural polymer derived from seaweed, moistened it to make a gel and mixed it with a type of water-dwelling bacteria that act photosynthesis, known as cyanobacteria.
The mixture was inserted into a three-dimensional printer, and after testing various three-dimensional printed geometries of their materials, the researchers found that the grid-like structure was optimal for keeping the bacteria alive, as the chosen shape has a high surface-to-volume ratio, which places most cyanobacteria close to the surface of the material to access nutrients, gases and light, and increasing the surface area makes the material more effective in removing pollution.
As a proof-of-concept experiment, the researchers genetically engineered the cyanobacteria present in their material to continuously produce an antiseptic enzyme called lacaz, and studies have shown that the enzyme can be used to neutralize a variety of organic pollutants, including bisphenol A (BPA), antibiotics, pharmaceutical drugs and dyes.
Get rid of the blue dye
In this study, the researchers demonstrated that their material can be used to disinfect contaminated Nile scarlet, a blue dye widely used in the textile industry.
The researchers also developed a way to eliminate cyanobacteria after removing contaminants, and genetically engineered the bacteria to respond to a molecule called theophylline, in which the molecule stimulates bacteria to produce a protein that destroys their cells.
"Living matter can act on contaminants of interest, and then a small molecule can be added afterwards to kill the bacteria, and in this way, we can alleviate any concerns about the presence of genetically modified bacteria remaining in the environment," says Pokorski.
The researchers suggest that the best solution is to have bacteria destroy themselves without adding chemicals, and this will be one of the future directions of this research.
"We're excited about the potential this work can lead to, the exciting new materials we can make, and that's the kind of research that can come together when researchers with interdisciplinary expertise in materials and biological sciences come together," Pokorsky adds.
Commercial production of the material
For his part, Pokorsky does not see any major obstacles to the commercial production of the material, saying in special statements via e-mail to Al Jazeera Net, that "the basic material is derived from algae and the resources necessary for the growth of cyanobacteria are available, namely air, water and light."
They can now think about potential use cases, whether it's large-scale water treatment or a smaller, more distributed network, he explains.
On the possibility of considering developing their new material to work with other pollutants such as plastic particles, a problem that has become more serious, he said, "We will work on this, as biology provides a range of potential resources that can be reused for environmental decontamination purposes, and the current material has the ability to disinfect industrial dyes, fine chemicals and pharmaceuticals, and we expect to integrate new biological functions in the future, including handling plastics."