BIOPRINTING OUR FUTURE BODIES
From chapter 6 (ELYSIUM, Films from the Future: The technology and Morality of Science Fiction Movies
In 2016, a quite remarkable series of images started to permeate the internet. The images showed what looked like the perfectly formed outer parts of a human ear. But, unlike a real ear, this one was emerging, as if grown, from an iridescent pink liquid held in a laboratory petri dish.
The ear was the product of a technique that scientists around the world had been working on for some years: the ability to, quite
literally, print replacement body parts. Inspired by developments in 3-D printing, researchers were intrigued to see if they could
achieve the same effects using human cells. The idea was relatively simple: If a matrix of living cells and a permeable but shape-holding material could be formed using a modified 3-D printer, it should be possible to build up three-dimensional human tissue samples, and even complete organs. Of course, the devil was in the details, as even the simplest tissue samples have a highly complex architecture of capillaries, nerves, connecting tissues, and many different cell types. But early enthusiasm for “bioprinting” 3-D tissue samples using sophisticated cell-containing inks, or “bio-inks,” paid off, and research in this area is now leading to quite revolutionary technological breakthroughs. And while Elysium-like medical pods that reconstruct damaged bodies in seconds will always be beyond our grasp, 3-D printed replacement body parts may not be as far off as we think.
The year 2016 might have been a landmark year for bioprinting, but it was far from the first successful attempt to 3-D print biological structures. Some of the earliest attempts to use 3-D printing technology with biological materials date back to the early 2000s, and by the mid-2000s, an increasing number of papers were beginning to appear in the scientific literature on bioprinting. But these early approaches led to materials that were very basic compared to naturally formed tissues and organs. Unlike even the simplest natural tissues—the cartilage that forms the structure of ears, for instance—they lacked the fine structure that is inherent in the stuff we’re made of. Scientists had begun to make amazing breakthroughs in printing 3-D structures that looked like viable body parts, but they lacked the essential ingredients necessary to grow and function as effectively as their biological counterparts.
This was only a temporary setback, though, and the 2016 ear was proof that the technology was progressing by leaps and bounds. The ear, created by Anthony Atala and his colleagues at Wake Forest School of Medicine, was printed from a bio-ink mix of rabbit ear chondrocytes—cells that form cartilaginous tissue—and a hydrogel that enabled a persistent three-dimensional structure to be formed while keeping the cells viable. The shape of the ear was based on a 3-D scan of a real ear, and when printed, it looked uncannily like a flesh-and-blood human outer ear. What made it unusual, though, was the inclusion of microscopically fine channels threaded through
its structure, allowing nutrients to diffuse to the cells and enabling them to stay alive and multiply. (The petri-dish ear was just one of three tissue constructs produced by Atala and his team to demonstrate their technique. They also bioprinted a mandible fragment of a similar size and shape to something that could be used in facial reconstruction, and a rat skullcap bone.)
Atala’s team effectively demonstrated that it’s possible to print simple body parts that remain alive and healthy long after the printing process is finished, and that are potentially useable as transplantable replacements. But despite this, bioprinting continued to be dogged by the extensive challenges of reproducing naturally- occurring biological materials, and doing this fast enough to prevent them beginning to die before being completed. It’s one thing to be able to print something that looks like a functioning replacement body part, but it’s something completely different to bioprint tissue that will behave as well as, if not better than, the biological material it replaces.
Part of the challenge here is the sheer complexity of human tissues. Most organs are made up of a finely intertwined matrix of different types of cells, materials, and components, which work together to ensure they grow, repair themselves, and function as they’re supposed to. Embedded within this matrix are vital networks of nerves and capillaries that relay information to and from clusters of cells, provide them with the fuel and nutrients they need to function, and remove waste products from them. Without comparable networks, bioprinted parts would remain crude facsimiles of the tissues they were designed to replace. But building such complexity in to 3-D printed tissues would require a resolution far beyond that of Atala’s ear, and an ability to work with multiple tissue types simultaneously. It would also require printing processes so fast that cells don’t have time to start dying before the process is complete.
These are tough challenges, but at least some of them began to be directly addressed in 2018 by the company Prellis Biologics. Prellis is working on a hologram-based 3-D bioprinting technology that, rather than building up organs layer by layer, near-instantaneously creates three-dimensional structures of cells and support material in a specially prepared liquid suspension. By creating a light hologram within the liquid, the technique forms brighter “hot spots” where the light-sensitive liquid is cured and set, creating a semi-solid matrix of cells and support material. If the “hot spots” are a three-dimensional representation of an ear, or a kidney, the living architecture for the 3-D-printed organ can be produced in seconds. But here’s the clever bit. Above the resolution of the system, which is a few micrometers, complexity is essentially free, meaning that it can be used to produce extremely complex three-dimensional tissue structures with ease; including embedding capillaries within the organ that’s being printed.
In other words, we’re getting close to a technology that can reproduce the structural complexity of something like a kidney, capillaries and all, in a matter of hours. Reflecting this, Prellis’ ultimate goal is being able to print the “entire vasculature of a human kidney in twelve hours or less.”
Whether this technology continues to develop at the current breakneck speed remains to be seen. I’m a little skeptical about how soon we’ll be able to print replacement body parts on demand, as biology is constantly blindsiding us with just how deeply complex
it is. But, despite my skepticism, there’s no doubt that we are getting closer to being able to print replacement tissues, body parts, and even vital organs. And while we’re still a world away from the fantastical technology in Elysium, it’s shocking how fast we’re beginning to catch up. With advances in high-speed, high-resolution and multi-tissue bioprinting, it’s conceivable that, in a few years, it will be possible to 3-D-print a replacement kidney or liver, or jaw bone, or skin grafts, using a patient’s own cells as a starting point. And even if we can only get part of the way toward this, it would revolutionize how we’re able to treat diseased bodies and extend someone’s quality of life. With kidney disease alone, it’s estimated that over 2 million people worldwide depend on dialysis or kidney transplants to stay alive, and the number of people needing a new kidney could be as high as 20 million. The ability to print replacement organs for these people could transform their lives. But why stop there? New livers, new bones, new hearts, new limbs; once we crack being able to print replacement body parts on demand that are fully biocompatible, fully viable, and act and feel just like their naturally grown counterparts, our world will change.
This is quite amazing stuff. In a world where there remains a desperate need for new technologies to counter the ravages of disease and injury, it’s a technology that promises to make millions of lives better. And yet, as Elysium reminds us, just because we can cure the sick, that doesn’t mean that everyone will benefit. As bioprinting-based medical treatments become available, who will benefit from them, and what are the chances of this leading to a two-tiered society where the rich get to live longer, healthier lives and the poor get to sit on the sidelines and watch? This is a scenario that already plays out daily with less sophisticated medical technologies. But if bioprinting turns out to be as revolutionary as it promises, it could drive a much bigger social wedge between people who are rich enough and powerful enough to constantly be upgrading their bodies with 3-D-printed parts and those who are destined to be left struggling in their wake.
This is the scenario that plays out in Elysium, as the inhabitants of the orbital enjoy access to medical facilities that those left on Earth can only dream of. But it’s only one of a number of ways in which powerful technologies lead to social disparity in the movie. Another, and one that is near and dear to my professional heart, as it’s an area I focused on for many years, is just how risky workplaces can become when their owners put profits before people, regardless of how sophisticated the technology they are producing is.