3D-Printed Bacteria Cages: Researchers Create Incredible Microscopic 'Zoos' To Observe Bacterial Interactions [STUDY]
We've seen 3D printers for everything from a prosthetic foot for a duck to space pizza to invisibility cloaks, and now we can add one more novel use to the list: microscopic bacteria "cages." Researchers at the University of Texas at Austin are studying how bacteria interact and infect people by housing the stuff in 3D-printed enclosures, creating little observable "zoos" of bacteria. The cages replicate biological conditions that bacteria would find in environments like the human body.
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"It allows us to basically define every variable," said Jodi Connell, a postdoctoral researcher at the College of Natural Sciences at the University of Texas. "We can define the spatial features on a size scale that's relevant to what a single bacterium feels and senses. We can also much more precisely simulate the kinds of complex bacterial ecologies that exist in actual infections, where there typically aren't just one but multiple species of bacteria interacting with each other."
The 3D printing of the cages starts with a gelatin substance which bacteria thrive in. The gelatin is liquid when warmed but becomes firm at room temperature. Photosensitive molecules in the gelatin react to the lasers of a 3D printer, causing the gelatin molecules to link together into whatever shapes the researchers desire. Those shapes are created when a digital film projector shows a 2D image in the gelatin, which the lasers then imprint.
"Then we do another layer, and another, and so on, building up," said Jason Shear, a professor of chemistry University of Texas. "It's very simple. We're basically making pictures and stacking them up into 3-D structures, but with incredible control. Think about the thickness of a hair on your head, and take 1 percent of that, and then take about a quarter of that. That's about the size of our laser when it's brought to its smallest point."
In a proof-of-concept experiment using the 3D cages, the University of Texas researchers arranged bacteria "core-and-shell," with the skin-infecting Staphylococcus aureus bacteria enclosed within a layer of Pseudomonas aeruginosa, a bacteria involved in a variety of diseases. The core-and-shell method gave the researchers the opportunity to see how both bacteria reacted when an intruder entered.
"[Staphylococcus and Pseudomonas] are really common bacteria that are often found together in infections, and it makes sense that they would have mechanisms to sense each other," said Shear. "What the technology allows us to do is put them in conversation with each other, in very precise ways, and see what happens. In this case the Staph sensed the Pseudomonas, and one result was that it became more resistant to the antibiotics."
The researchers detail their methods in a study titled "3D printing of microscopic bacterial communities," published in today's Proceedings of the National Academy of Sciences.
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