This past summer, a plane went into an ascent and plunge 30,000 feet. The goal was not thrill-seeking, but something more daring: for about 25 seconds at a time, the parabolic flight lifted the occupants into a state of simulated weightlessness, allowing a high-tech printer to spit out cardiac stem cells into a simplified structure of an infant’s heart.
Impressive though this may be, it’s just a brick in the road toward an even bolder goal. Executives at nScrypt (the makers of the stem cell printer), Bioficial Organs (the ink provider), and Techshot (who thought up the heart experiment) are planning to print beating heart patches aboard the International Space Station by 2019. The printer will fly up on a commercial rocket.
Private spaceflight companies like Blue Origin and SpaceX have been criticized as vanity projects for plutocrats surfing on taxpayer investments. But the emergence of these companies has led to nose-diving prices for sending goods and equipment into space. Today it costs roughly $5,000 to launch one kilogram of stuff, compared to $30,000 during the space shuttle era.
So a growing number of entrepreneurs and researchers are looking to use this relatively cheap access to harness the unique qualities of low Earth orbit—including its vacuum, microgravity, unlimited solar power, and extreme temperatures—for manufacturing. Their experiments are already spurring innovations in medicine, technology, and materials science. Eventually, if it takes off, orbital fabrication could revolutionize the way we make things.
A heart transplant patient can spend months waiting for a new ticker. After he gets one, he’ll need to take immunosuppressants for the rest of his life, so that his body won’t reject the foreign organ. A heart printed from the patient’s own stem cells could get to him faster, with a lower chance of immune rejection. It could also be perfectly tailored to fit the dimensions of his original heart.
But it turns out that gravity is a real problem when it comes to printing hearts on Earth. For printable bioinks to grow, the broth of stem cells and nutrients needs to have a watery consistency to ensure the cells are mobile enough to knit together into healthy heart tissue. Because of this watery consistency, to grow a heart on Earth, you need a support structure.
“If you think about the heart, you’re really talking about four big open voids wrapped in muscle,” says Eugene Boland, chief scientist at Techshot. Unfortunately, scientists haven’t devised a scaffold for growing stem cells that can later be removed or dissolved without damaging the nascent organ.
By printing organs in space instead, Techshot thinks it can grow whole hearts without the use of a scaffold.
“If we try to do it on Earth, it would look pretty for about a second and then just kind of melt all over the table,” says Boland. “It would look like you just poured a Jell-O mold and then tried to immediately serve it, it would glob on your plate into this gelatinous mess.”
But microgravity helps the heart maintain shape without a scaffold. That’s partly because low gravity makes printing 3D shapes more direct. On Earth, complex 3D objects such as a model heart need to be printed as 2D layers that are overlaid on top of one another in a time-consuming process. nScrypt CEO Kenneth Church calls this “2-and-a-half-D.” Printing in microgravity allows the object to be spit out in genuine 3D, improving speed by up to 100 times.