Two groups of undergraduate students at Duke University have been creating biomedical devices for their senior design projects with a campus rarity – a titanium 3D metal printer.

Over the past few years, 3D printers that make plastic objects have become somewhat commonplace – Duke’s Innovation Co–Lab has more than 60 of them for use by faculty, staff and students. Metal 3D printers, however, are an entirely different beast, requiring much more infrastructure and a steeper learning curve.

But as the Duke students working out the kinks in the system this past year will tell you, it’s been well worth the investment.

“The metal 3D printer allows us to make designs that could never be fabricated by traditional manufacturing processes,” said Sam Morton, a senior studying mechanical engineering. “It allows us to make actual biomedical devices out of titanium that we can then test and get feedback on from the surgeons we’re working with.”

“The turnaround is so quick,” echoed Dr. Robert Isaacs, associate professor of neurosurgery at the Duke University School of Medicine, who is working with Morton on his project. “You come up with a plan or notice a problem in a prototype, and then almost in no time, Sam comes back and delivers exactly what you just said. You think it, and then you’re holding it. It’s incredible.”

The two groups of seniors are pursuing separate biomedical devices – an intricate titanium spacer for spinal fusion surgeries and titanium scaffolds for large bone defects. Both share common requirements and challenges.

Spinal fusions are common procedures meant to alleviate back pain caused by two vertebrae rubbing together as a disc of cartilage fails. Surgeons insert the device resembling a small, hollow Lego between the two vertebrae, promoting the growth of bone around the device to fuse the two bones and stop future movement.

Similarly, titanium scaffolds provide strength and support to surgically removed portions of other bones while encouraging regrowth.

Current devices for both procedures however, have several drawbacks. Metal–based devices are often too hard and opaque to the imaging technologies doctors use to see how well the bone is growing. Plastic devices are not as strong and do not facilitate as much bone growth. The two senior design projects sought to create 3D printed devices that would have the best of both worlds. Complex, sponge–like details encourage bone growth in and around the implant while minimizing the amount of metal used and allowing doctors to image the results afterward.

“The titanium 3D printer is a really great opportunity because it lets you create structures that you couldn’t make using normal manufacturing techniques,” said Samantha Sheppard, also a senior in mechanical engineering. “We’re able to create porous structures that are better for bone ingrowth and that really could only be made with this printer.”