Space may be the final frontier, but to boldly go where no one has gone before will require the development of new technology that allows humans to travel farther into deep space. One such technology may be bioprinting, given its potential to 3D print critical tissues for treatment in a place that’s far from any hospital.
Rendering of Techshot and nScrypt BioFabrication Facility in an EXPRESS rack. (Image courtesy of nScrypt.)
To begin bioprinting efforts in space, two well-established companies, Techshot and nScrypt, have partnered to create the 3D BioFabrication Facility (BFF), which is set to make a journey to the International Space Station (ISS) in February 2019. To learn more about the technology and the upcoming mission, engineering.com spoke to nScrypt CEO Ken Church and Rich Boling, vice president of Corporate Advancement at Techshot.
In 2016, the partners demonstrated the ability of a BFF precursor to 3D print cardiac and vascular structures in zero gravity with adult human stem cells.Why 3D print heart tissue in microgravity? On Earth, it’s nearly impossible to fabricate tissue with sufficient thickness, without using a scaffold. A scaffold, however, can also be an obstacle to the mobility of cells, nutrients and growth factors, according to Church.
The above vascular structure was bioprinted aboard a microgravity flight. (Image courtesy of Techshot.)
“While petri dishes are excellent in the lab, many of those struggle beyond a certain thickness. How do we get to that thickness? That’s the question,” Church said. “A lot of groups have made proclamations about growing [organs], but I think we should all be clear and honest about that. What we’re doing at this point is growing grafts, such as a skin graft or a bladder graft. If you want to grow a complete organ, you have a whole 3D structure that you must deal with. Today we use scaffolds, and that is a great and promising way, but scaffolds sometimes get in the way.”
Because scientists haven’t yet developed a scaffold that can be removed or dissolved without damaging the growing tissue, Church wondered if it might be possible to print stem cells without using a scaffold and without gravity. The team hypothesized that a material with low viscosity might form a puddle on Earth but could possibly hold its structure in microgravity, making a scaffold unnecessary.
The Techshot and nScrypt team was thrilled to see its hypotheses proven during parabolic flight tests, with the bioprinter successfully fabricating not a two-dimensional layer of tissue, but an actual three-dimensional structure. Once gravity returned a minute later, however, the heart tissue compressed to half of its height. On the ISS, the team believes that it might be possible for the stem cells to maintain shape while they grow into a beating heart.
Once the BFF is installed aboard the ISS, it will perform some initial prints before 3D printing a cardiac patch designed to heal a damaged heart. Key to the experiment is the bioreactor cassette, which provides nutrients to the tissue and removes toxins, while also using electrical and mechanical stimulus to push the cells into becoming beating heart tissue.
In addition to being designed to 3D print organic tissue in space, the BFF is capable of producing thick, vascularized tissue, a notoriously difficult task in the world of bioprinting. This capability is due in part to nScrypt’s more than15 years of experience in the bioprinting arena.
The BFF consists of a customized and space-hardened nScrypt 3D Bio Assembly Tool (BAT), in which bioink is 3D printed into a cell culturing bioreactor cassette designed by Techshot and conditioned in the company’s Techshot ADvanced Space Experiment Processor (ADSEP). nScrypt is known for its fine and precise dispensing technology, with the firm’s SmartPump, which is featured in the BFF, able to 3D print details as fine as 10 microns with 100 picoliter volumetric control.
While nScrypt is an expert at 3D printing, Techshot has over 30 years of experience in making hardware that can be flown into space and function in zero-g, a process Techshot’s Rich Boling described as “flyabilization.” “We saw an opportunity to expand our catalog of on-orbit hardware and never entertained the idea of working with anybody other than nScrypt to make this happen,” Boling said.
He went on to describe some of the features necessary to flyabilize nScrypt’s BAT 3D printer. This included making the machine robust enough for launch and using certain materials, types of wire and specially soldered circuit boards to meet NASA’s specific requirements.
To properly culture the tissue once it’s been printed, the team will be using Techshot’s ADSEP payload (seen in the video above), which has been flown on two Space Shuttle flights and once on the ISS (seen in the video below). The stem cells will be printed into a tissue culture cassette, which an ISS crew member will remove and insert into the ADSEP. There, it will remain for 45 to 60 days, with nutrients flowing through it and waste being removed, ultimately forming a heart patch that, when stimulated electrically and mechanically, will actually beat like organic heart tissue.
“Our first experiments are very much related to how the zero-g environment is going to affect cell mobility,” Chruch said. They will test the ability to 3D print stem cells in vertical, horizontal and other orientations to determine how this affects the movement of cells. Church anticipates that, without the pressure of gravity, the tissue should become thicker than is possible on Earth.
The Final Frontier
These experiments will then be returned to Earth aboard a SpaceX rocket, the only vehicle capable of retrieving objects from the ISS, at which point the Techshot and nScrypt team will analyze its work. If successful, the team will then send up materials for evermore complex tissues and, possibly, even organs, ultimately building toward the goal of aiding journeys into deep space.
With a BFF aboard a deep space vessel—or the Lunar Orbital Platform-Gateway meant to orbit the moon—crews could 3D print organs or tissue necessary for life-saving procedures. Additionally, because nScrypt has demonstrated the ability to print with a wide variety of media, we can imagine a similar system being used to print medicine, food and other objects.
However, the partners don’t aim only to print organs in space, but also hope to use the technology on Earth. “Everyone [on the team] has their reasons for why they’re performing this work, but many of us are touched personally by some kind of issue in our families or something where, if we could grow tissue to this extreme of a level, we could actually help them,” Church said.