3-D Printing May Save Your Life
3D printing has come a long way in recent years – with low cost on-demand printing services like Shapeways available to everyone, DIY open source printer kits going for $600 (or even less), and steady progress in the professional sector, it’s easy to forget what it was like before we could just send a file out and have a unique physical part within hours. The kinds of things that this enables are really pretty remarkable, and they extend well beyond the realm of typical product design that we’re used to. For example, Cornell University researchers recently made headlines by using 3D scanning and printing in their quest to help patients overcome a congenital deformity called microtia. Children born with microtia usually have functional inner ears so they should be able to hear, but the external ear is severely deformed or totally missing so their hearing ends up being greatly impaired. What surgeons are doing now is carving a new ear from the patient’s own rib or from a foam material, but as you can probably imagine, the resulting ears aren’t exactly ideal functionally or aesthetically (and the process is not very pleasant for a young child!). So, Jason Spector and Lawrence Bonassar at Cornell took a 3D scan of a healthy ear (potentially the patient’s own ear since microtia doesn’t always affect both sides), used a specialized 3D printer to create the resulting model in a hydrogel material, injected it with collagen and then implanted it with millions of cartilage cells. The result is a reasonably accurate copy of a functional ear made out of living tissue – all within about a day and a half. Currently they’re still using animal cells and one of the major remaining challenges is getting human cartilage to grow reliably in a lab, so unfortunately they are not quite ready to implant the ears in human patients, but they have proved it will be possible.
Copying something as complex as a living ear is a pretty impressive feat, but being made of cartilage means they don’t need blood vessels in their structure so they’re much simpler than other organs that it would be nice to make copies of. Creating structures as intricate as blood vessels out of living cells is an enormous challenge, but luckily some progress is being made. A biotech company called Organovo is working with Autodesk to develop 3D bioprinters that do exactly that. So far they can only create tissue fragments up to about 1mm in size, but even that is apparently enough to be useful for pharmaceutical testing already. Researchers at the University of Pennsylvania and MIT are pursuing an alternate solution to the same problem using a modified low-cost 3D printer and sugar. In a surprisingly simple process that has parallels to the age old process of lost wax casting, the researchers simply printed out a network of suspended strands of sugar (a mixture of sucrose, glucose and dextran to be more precise) surrounded by a wall, flooded the cavity with living cells suspended in a gel, then when the gel hardened they flushed out the sugar with water leaving behind living tissue with an internal vascular structure. They were even able to pump nutrient-rich liquid through the channels to keep the surrounding tissue alive, not far off from how natural tissue and blood vessels function.
It’s pretty humbling to see accomplishments like these when I think about the amount of time and effort it took for me just to build a simple FDM 3D printer (a MendelMax 1.5), but I’m always fascinated by what’s possible when people push the technology to new limits.