Scientists at Lawrence Livermore National Laboratory scientists have developed a method for 3D printing of living microbes, enhancing the potential to use engineered bacteria in a variety of industrial processes such as recovering rare-earth metals, cleaning wastewater, and detecting uranium.

Through a novel technique that uses light and bacteria-infused resin to produce 3D-patterned microbes, researchers successfully printed artificial biofilms that resemble the thin layers of microbial communities that occur in the natural world.

The researchers suspended the bacteria in photosensitive bio-resins and “trapped” the microbes in printed biofilms as thin as 18 microns – nearly as thin as the diameter of a human cell – using LED light from a 3-D printer, also developed by LLNL, called the Stereolithographic Apparatus for Microbial Bioprinting.

“We are trying to push the edge of 3D microbial culturing technology,” said LLNL bioengineer William “Rick” Hynes. “We think it’s a very under-investigated space and its importance is not well understood yet.

“We’re working to develop tools and techniques that researchers can use to better investigate how microbes behave in geometrically complex, yet highly controlled conditions,” Hynes added. “By accessing and enhancing applied approaches with greater control over the 3D structure of the microbial populations, we will be able to directly influence how they interact with each other and improve system performance within a biomanufacturing production process.”

Although they may seem simple, Hynes said microbial behaviors are extremely complex and are driven by spatiotemporal characteristics of their environment.

How microbes are organized can affect a range of behaviors, such as how and when they grow, what they eat, how they cooperate, how they defend themselves from competitors, and what molecules they produce, Hynes said.

Previous methods for producing biofilms in the laboratory offered scientists little control over microbial organization within the film, limiting the ability to understand the complex interactions seen in bacterial communities in the natural world, Hynes explained. The ability to bioprint microbes will allow scientists to better observe how bacteria function in their natural habitat and investigate technologies such as microbial electrosynthesis, in which “electron-eating” bacteria convert surplus electricity during off-peak hours to produce biofuels and biochemicals.

Results of the LLNL research was reported in a paper published in the journal “Nano Letters.”