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This new slime bath could help scientists 3D print the medical implants of the future

So it works kind of like a Jello salad

3D printing in a slime bath boosts precision

This slime bath could be the future of 3D printing medical implants.

Posted by The Verge on Thursday, May 11, 2017

A newly developed goop could be the key to 3D printing delicate objects. Scientists have discovered that suspending fragile 3D-printed structures in a Jello-like goo while the liquid ink hardens keeps them from warping or sagging. This could eventually improve the manufacturing of things like personalized medical implants — but for now, the new technique is still in its proof-of-concept stages.

Say you want to 3D print a thin, hollow, or otherwise fragile object — like a replacement windpipe, for example. The 3D printer lays down layers of a material like silicone until enough builds up to form a tube. But there’s this lag time between when the printer first squirts out the liquid ink, and when that ink solidifies — which presents a problem: how do you keep your structure from collapsing or bending before it fully hardens?

Video: Science Advances

That’s why researchers led by Thomas Angelini and Chris O’Bryan at the University of Florida developed a new material called an organogel that can support the liquid ink as it hardens. It’s made out of squishy, microscopic, chemical balls that are packed together in mineral oil, according to their new study published in Science Advances.

“I like to explain it like a ball pit in McDonald’s,” O’Bryan says. “Just, shrunk down to sizes that are one-hundredth the size of a human hair.”

The gel is basically a microscopic chemical ball pit, where squishy balls of gel are packed together in oil.
Video: Science Advances

Under most conditions, the organogel acts like a gooey solid that envelopes the 3D-printed structure and keeps it immobile. But during the actual printing process, the 3D printer’s nozzle puts just enough pressure on the organogel that the goo turns into a fluid right at the tip — flowing around the nozzle as it squirts silicone ink in a 3D pattern. The nozzle is kind of like the kid in that ball pit: it can push the balls aside, but as soon as it passes, the balls fall back into place behind it.

Using this new setup, the scientists 3D printed an extremely thin-walled windpipe that took 24 hours to harden — time when it could have bent or collapsed without the organogel’s support. They also printed out what they affectionately call the “sea anemone,” a strange little Cthulhu creation that squirts water through its tentacles.

Video: Science Advances

The reason they made their little water-squirting monster and another tiny eyedropper-looking pump was to show that objects printed with this new technique were tough enough to pump liquid without bursting or leaking. This will be important if this method is ever harnessed for 3D printing more streamlined, customized medical implants. In fact, most of their creations were hardy enough for the researchers to scoop them out of the support gel and wash off — except for a particularly delicate mesh that was too flimsy to be moved.

Video: Science Advances

Custom-printed medical implants are already out there: a man received a 3D-printed replacement for a missing part of his skull a few years ago, and a 3D-printed tube shored up an infant’s windpipe in 2012 after a birth defect left the child unable to breathe. The advantage of this new method, the authors write in their study, is that it allows for much finer and more precise printing. Until it finds its way to the clinic, the scientists could always use their new technique to make their little tentacled Cthulhu some friends.

Video: Science Advances