3D printing has grown from a niche manufacturing process to a $2.7-billion industry over the past two decades, and now scientists are working to apply 3D printing technology to the field of medicine by printing with living cells.
More sophisticated printers and software, and advances in regenerative medicine have made this possible.
Kevin Shakeshaff, a professor of pharmacy at the University of Nottingham in England, has been working on technology that can “print” a custom body part. An image of a jawbone defect can be fed into a computer and a replacement can be printed to precisely fill the defect using the patient’s own cells, Shakeshaff explains.
“The tissues of our body are structured at the level of single cells – using 3D printing, we can position cells in precise places.”
To print this type of bone replacement, the 3D bio-printer creates a scaffold in the bone shape and coats it with adult human stem cells, which can develop into many different tissue types. The printer’s “ink” consists of a polymer called polylactic acid and a gel-like substance called alginate. This delivers the hard, mechanical strength of bone, along with a cushioning material for the cells. The printed artificial bone can be implanted in the body, where the scaffold will degrade and be replaced by new bone grown by the body within about three months.
“The first advantage is you get something in the exact shape of the defect you’re trying to replace,” Shakeshaff says. “More subtly, you have the ability to organize where the cells go within the scaffold,” which leads to better blood vessel formation and ultimately better bone formation.
Researchers at MIT have also developed a new approach to designing and printing artificial bones. By using computer optimized designs of soft and stiff polymers placed in a pattern to replicate nature, they are testing 3D printed artificial bones that are durable, lightweight, and environmentally sustainable.
“This research is a wonderful example of how 3D printing can be used to fabricate complex architectures that emulate those found in nature,” says Jennifer Lewis, professor of Biologically Inspired Engineering at Harvard University.
Perhaps a more common need than regenerating a bone, is fixing a broken one. When Jake Evill, a design student at Victoria University in New Zealand, broke his hand it made him think that the whole plaster or fiberglass casting process was woefully outdated. So, he designed an improvement. His idea uses input from an X-Ray, plus a 3D scan of the broken limb and feeds the dimensions and data into the computer to create an exoskeleton-type cast that looks like it could be part of a Spiderman outfit. The prototype is called the Cortex cast and it protects the broken bone with optimal support and an exact fit.
To create the cast, the broken limb is 3D scanned and the data is reconstructed into a 3D model. The output from that process is a digital file which then goes to a 3D printer. The resulting cast is ultra-light, hygienic and anatomically accurate. Made from nylon, it snaps together easily and applies the appropriate pressure on the fracture or break point.
The Cortex cast is also breathable, lightweight, recyclable and washable. It is less bulky than a regular cast and also lets in plenty of air, which prevents that stuffy, itchy feeling.