A team of researchers in Holland have pioneered an inexpensive method for 3D printing bacteria into shapes and patterns, opening the door to a wide range of potential real-world applications from mother-of-pearl fake teeth to powerful new microlenses that boost the effectiveness of solar panels or cameras.
The lab is already using the technique to 3D print plaque onto cow’s teeth as a potential avenue for studying oral hygiene.
The technique could also be used in the bacterial production of graphene, the one-atom-thick material that is both the thinnest and the strongest compound ever discovered, with over 100 times the strength of steel.
“The possibilities are really wide-ranging — I could imagine materials in so many different categories,” said Dr. Anne Meyer of the Delft University of Technology in the Netherlands, one of the lead scientists of the team and an author of a paper on the technique.
Once viewed as something of a novelty, 3D printing has found a widening variety of applications from the production of artificial bones and organs to a candy store in Chicago that lets customers 3D print gummy bears into any shape they want. In 2014, astronauts 3D printed a special wrench in space to repair their spaceship after NASA sent only a digital design file for the tool to the craft.
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The team in Holland developed their method by modifying a $300 commercial 3D printer.
That low price tag is significant, because it makes the approach widely reproducible. Techniques for cellular printing for biological or medical applications are generally much more expensive, ranging from $5,000 to $200,000.
Over-the-counter commercial 3D printers operate by heating plastic to make it liquid enough to be patterned by the print-head. But that kind of heat kills bacteria.
So the team removed the heater from the print-head, and affixed a syringe filled with liquid bacteria. They used a syringe pump controlled by a custom computer program to control output.
“Then we had to develop some chemistry to make sure the bacteria stays where you print it,” Meyer said.
That involved mixing the live bacteria with a polymer called alginate, which solidifies when it touches calcium ions.
“As long as we have calcium on the surface, then as soon as the bacteria hits it, our stripe of bacteria becomes a rigid scaffold,” said Dr. Meyer.