Lipson is convinced that by democratising manufacturing and invention, 3D printing will change the world. “It’s nothing short of an industrial revolution,” he says. And the Fab@home kit isn’t the only option. Other open-source projects include RepRap, a 3D printer that is designed to be able to print replicas of itself, invented by Adrian Bowyer at Bath University, UK.
The immediate fruits of this personal manufacturing revolution will come from simple problem solving, like replacement glasses. But the world of medicine offers far more intriguing opportunities, and for many in the developing world it will provide a vital lifeline in villages and towns where there currently is none.
For instance, it’s not in the realm of fantasy to imagine printing replacement organs by squirting living cells rather than drops of ink. Organs could be created for transplant patients without any fear of an immune reaction, or new heart valves for transplanting directly into a patient on the surgeon’s table. These technologies are being developed already, albeit with extremely sophisticated printers. Simpler organs like skin, windpipes or blood vessels, will be the easiest to create, more difficult will be hollow sac-like organs, like the bladder or stomach, and hardest of all will be solid organs like the kidneys, heart and liver.
But there have been some notable achievements. Anthony Atala from the Wake Forest Institute for Regenerative Medicine in North Carolina printed a kidney, though a non-functioning one, on stage at a TED conference last year. Biologist Jonathan Butcher, Lipson’s colleague at Cornell, has already 3D-printed a working heart valve out of biological polymers. 3D printing allows complicated structures to be built easily, says Butcher. A heart valve has areas that need to be stiff and strong, other areas that need to be flexible, and a host of interconnecting, moving parts. Building a system as intricate as that using a mould instead would be mind-numbingly difficult Butcher suggests. “Anytime a tissue is anatomically complex... 3D printing will make a major impact,” says Butcher.
So far, Butcher has printed aortic heart valves and put them in a bioreactor, where stem cells are added that integrate with the polymers and eventually take over so that the valve is made entirely from human cells. The next step is to try this in an animal model, and Butcher is aiming for 2013 for that. The developments needed now are in the materials used as the inks, says Lipson, who is working with Butcher on the project. “Once people figure out the process it doesn’t require hi-tech,” says Lipson. Butcher agrees: “we’ve got the printing thing worked out,” he says.
Butcher anticipates that 3D printing could slash the cost of organ transplant surgery and help bring it to the developing world. “Some of the major costs for organ replacement are the limited supply and the transportation and storage costs,” he says. “3D printing-based tissue engineering creates a new organ from scratch, fundamentally removing those costs.” And even though new materials are needed, they needn’t be prohibitively expensive either. “We currently use about $10 of polymer to print a human sized heart valve,” says Butcher.
Personal medicine
Lipson also thinks that 3D printing could help to train doctors and surgeons. Removing a tumour accurately, for example, he says, could easily be practiced if a scan of the tumour site is made and then a replica printed. “There are ethical and cost issues with cadavers and animals, but a 3D printer can recreate what you need,” Lipson says. Not only that, but the texture of live tissues can be recreated: rigor mortis makes cadavers stiff and unrealistic for someone who wants to learn what surgery on a live patient really feels like.
