How to rebuild your body with 3D-printed parts
3D printers can do more than just print metals and plastics: soon they’ll save lives too. As the 3D Printshow 2013 prepares to come to London, here’s our round-up of the cutting-edge ways in which biological printers are reshaping medicine. Sedeer El-Showk investigates...
Blood vessels are challenging to grow in the lab, but without them artificial organs would starve for want of nutrients. A team of bioengineers at the University of Pennsylvania has overcome this hurdle with a 3D printer that builds blood vessels from the inside out. The printer lays down an intricate network of sugar filaments to serve as a template for the inside of the vessels. A suspension containing the patient’s liver cells is added, and the cells grow around the sugar to form vessels. The sugar strands are then washed away, leaving behind a living network of blood vessels.
Eric Moger lost the left side of his face as a result of cancer several years ago. Chemotherapy eliminated the possibility of plastic surgery, leaving him with a gaping hole in his face. Thanks to 3D printing, he received a lifelike prosthetic face made of toughened nylon plastic earlier this year. Surgeons printed a mirror image of a 3D scan of the right side of his face, which was then attached to a titanium scaffold.
For less drastic cases, researchers at the Wake Forest Institute for Regenerative Medicine are working on a 3D printer that can print living cells directly onto burns and other wounds.
With nearly 50,000 cases of breast cancer diagnosed in the UK every year, there’s high demand for reconstructive surgery. Partial reconstruction following removal of only the tumour is especially difficult, leaving women with few good options. Research at the University of Texas at El Paso promises to fill the gap by printing a shape-fitted custom implant from the patient’s own fat cells. Using a modified HP Deskjet printer, they lay down layer upon layer of cells to create an implant that fits the excision while minimising the risk of rejection or other complications.
There are obvious advantages to 3D-printed bones – not only can they be custom-fitted to the break, but the technology is ideally suited to mimic the internal structures that make natural bones light and resilient. In June 2011, an 83-year-old woman in the Netherlands got a 3D-printed prosthetic lower jaw. Made of titanium powder fused together by a laser, it had working joints as well as cavities and grooves for muscles and nerves to reattach.
More like this
Just this year, US company OsteoFab went even further when they used 3D printing to replace most of a patient’s skull. Car crashes and other serious accidents can call for this sort of major reconstructive surgery, and 3D printing offers the necessary precision and speed at a much lower cost than traditional methods, making these operations cheaper and safer.
Amputees can reap the rewards of 3D printing too: printed prosthetics can be custom-fitted, avoiding the need to trim the bone. They’re also cheaper to make and easier to replace than traditional titanium or carbon-fibre limbs. Projects like Handie and Dextrus (see below), which are developing robotic hands, promise to dramatically cut the costs involved and bring these life-changing devices within reach of people with lower incomes.
Replacements for missing or underdeveloped ears are currently built using artificial materials or from transplanted rib tissue, but the results often look unusual and don’t perform very well. A team of doctors at Cornell University plans to remedy this with lifelike bioengineered ears. A 3D printer is used to print a mould that then serves as a template to shape the growth of collagen and cartilage. It takes only a few days for the ears to grow, and they can stay alive and healthy in the lab for several months. If the safety and efficacy tests go well, we may hear about the first human implant in just a few years.
Anthony Atala, the director of the Wake Forest Institute for Regenerative Medicine, is on a mission to make functional human organs with a 3D printer. The printer first builds a scaffold structure upon which it deposits layers of cells that combine to form an organ.
Atala has already successfully printed and implanted a bladder, and now he’s set his sights on more complex organs like the kidney and liver. His team has printed a kidney out of human cells, but getting it to work is the trick – for one thing, it needs proper blood vessels to function. While they work on that, the same technology has been used to print clusters of organ cells, like liver cells, which can be used in place of animal testing.