Taking inspiration from the natural materials like bones and minerals, the researchers at Massachusetts Institute of Technology (MIT) have created first man-made living materials using E.coli bacteria. The unique feature of this new invention is that the created material has properties of both living and non-living things.
The researchers coaxed the bacteria cells to produce biofilms that can incorporate nonliving materials like gold nanoparticles and quantum dots.
Timothy Lu, an assistant professor of electrical engineering and biological engineering, and his colleagues have shown that it is possible to incorporate gold nanoparticles and even quantum dots to create “living materials.”
Illustrating examples, he say, self-healing material could help absorb and conduct electricity in solar cells. These materials could also spot tears and fix themselves without an external command.
In a news release, Lu said, “Our idea is to put the living and the nonliving worlds together to make hybrid materials that have living cells in them and are functional. It’s an interesting way of thinking about materials synthesis, which is very different from what people do now, which is usually a top-down approach.”
The new invention is a simple representation of the power of this approach, which according to the researchers could pave the way for futuristic self-assembling materials that could be used in solar cells and biosensors.
Lu and his colleagues worked with the bacterium E coli to create the new material in lab. E coli was used as it naturally produces biofilms that contain so-called “curli fibres” – amyloid proteins that help E coli attach to surfaces. These fibers are made of a chain of protein subunits called CsgA and help the bacteria attach to the surface.
To develop the material, researchers essentially hijacked “biofilm production” to force bacteria to use gold nanoparticles and quantum dots. The cells were also engineered so that they could communicate with each other and change the composition of the biofilm over time.
The natural ability of bacterial cells to produce CsgA were diabled and then it was replaced with an engineered genetic circuit that produces CsgA but only under certain conditions — specifically, when a molecule called AHL is present. The researchers programmed these cells to produce different types of curli fibres under certain conditions. This helped them to control the biofilms’ properties and create gold nanowires, conducting biofilms, and films studded with quantum dots, or tiny crystals that exhibit quantum mechanical properties.
The research was published in the journal Nature Materials.