Scientists aim to 3D bioprint human tissue in space

Earlier this month, the SS Sally Ride cargo capsule made its way to the International Space Station. The spacecraft was carrying hundreds of pounds of scientific experiments. One of them involves what’s called a 3D BioFabrication Facility, which can build human tissue and organs in space that scientists can’t make on Earth.

Marketplace’s Kimberly Adams speaks with Rich Boling, vice president at Redwire, which manufactures the equipment for these experiments. She asked him about how 3D printing works when you’re printing something that’s alive. The following is an edited transcript of their conversation:

Rich Boling: Printers that you might have in your office or at home have ink. And so, our bio printer also uses bio inks. Sometimes we use stem cells, sometimes we use very specific types of cells, muscle, vasculature, nerve, and mix that with a media — a nutrient media that keeps those cells happy and alive. And when you mix the two, then that’s how you create a bio ink. And our bio printer for space holds four separate bio inks at a time. We literally upload a file of what we want to print and the device goes to work with those four bio inks laying down layer upon layer upon layer, to print a construct. 

Kimberly Adams: What’s the benefit of 3D bioprinting in space? 

Boling: On Earth, when you want to bioprint a construct, as we call it, which is just a 3D assemblage of layers of cells, those layers tend to flatten out under the pull of gravity and settle out. So, it just never really can get very thick very effectively. You have to add in scaffolding, and that’s very difficult to do without adding things that can be lethal to the cells. But in space, there’s no sedimentation. You can bioprint and create a 3D construct that stays where you put all those elements.

Adams: Gravity really seems to be the issue here — this idea that the weight of the atmosphere can crush these very delicate structures that you’re trying to print. What about microgravity makes that process more effective? 

Boling: Things stay where you put them, that’s really the essence of it.  I can build even a void, a chambered heart, for example, in the “zero G,” or microgravity, and it doesn’t collapse. And you don’t need to add in these the scaffolding. 

But one might ask, “Well, what good is doing that in space to people on the ground who really need those tissues?” And you’re right. If we actually did the printing, put it back in the capsule and brought it back down from the International Space Station immediately, it would collapse. It would turn right back into almost a puddle that you would get on Earth, which is why we don’t.  

We do our printing inside of a special cassette and then [the astronaut] takes this cassette out of the bio printer to another one of our devices onboard the space station. And we actually apply to that printed construct all the same factors that your body does when you want to build your muscles at the gym. And then, eventually, over a period of weeks, you do have a piece of tissue.  

So we never say we print tissue. We print with cells, we condition into tissue, and then you can bring it back down to earth and it survives the pull of gravity. 

Adams: Describe for me what it looks like: this structure that you 3D print, compared to what comes out at the end of conditioning that you can safely bring back to Earth. 

Boling: So it really looks the same. You would have to look at it under a microscope to see the preconditioned series of layers. I don’t know if you’ve ever seen something that’s been 3D printed out of plastic — you can actually see one layer on top of the other saw this striation of layers. And on a microscopic level, that’s also what you’re seeing when you’ve just printed the construct. And we use bio inks that are not much thicker than water, because what you want to cell mobility you’d like to have, as the cells grow, and we feed them and they multiply, that they can grow into the layer above them or below them or move around and in three dimensions into one another and grow into each layer. But under the microscope, you would definitely see: before, a bunch of layers; and after, just one solid piece of tissue. 

Adams: So what we’re talking about here is: if I need a heart transplant, rather than going on a waiting list, you could take some parts of my own body and 3D print a heart for me at some point? 

Boling:  That certainly is the goal. It’s 22 people a day who are dying in the U.S. on organ donor waiting lists. And ultimately, we believe this is a solution for that. 

Now, again, this is not happening next year — I just want to set expectations for that — but it’ll be never if we don’t do what we’re doing this year and next year, and the next. And along that road to that goal, there certainly is applicability that improves human health along the way, too.

Related links: More insight from Kimberly Adams

Even if the space experiments are just getting started, some 3D bioprinting tech is already being deployed here on Earth. Last July, doctors used the cells from one patient to bioprint a new ear for her. Since it was made with the patient’s own cells, the ear was less likely to be rejected by her body. The transplant was part of a clinical trial of 11 patients, and the surgery was the first known example of using a bio printed implant made out of living tissues.

On the other hand, printing full-size organs will be far trickier than printing cartilage, which is less likely to collapse. As we just heard, microgravity is one possible solution for that dilemma. But scientists at Carnegie Mellon University have devised a way to suspend delicate structures in gelatin to stop them from collapsing on this planet. The YouTube science channel “Seeker” has a video showing the process in action.