Scientists Are Now 3D Printing Human Tissue Inside the Body: Here’s What That Means

May 27

Written By Michele Edington (formerly Michele Gargiulo)

Medical Disclaimer: While most bioprinting takes place in laboratories using tissue models, a truly in-body printing method (called DISP) has recently been demonstrated in animal studies, but remains experimental and far from human medical use.

Tons of people die each year waiting on an organ transplant. That’s not new news, according to UNOS, around 13 people per day or around 6,000+ per year. My uncle was one of them, so I’ve seen the devastation up close from this sort of tragedy.

We’ve tried so many things to get these numbers down, from using animal organs to mechanical ones that keep you alive until the organ you need becomes available. This is the first time though, I’ve read about 3D printing them.

From Ink to Organ

The future of walking into a clinic with a worn-out joint or an ulcerated organ and walking out with newly printed tissue forming inside you without using scalpels is pretty absurd to think about.

Scientists have developed a way to 3D print living tissues directly into the body, just hop skip and jumping over the need for external implants or surgical trauma (if you’ve ever had surgery you know what I’m talking about). The printer which is sometimes as thin as a pencil, uses a bio-ink made from living cells, growth factors, and nutrients. It’s like a pencil dipped in life itself, ready to write an organ into place.

Guided by real-time imaging and AI, these robotic tools deposit living gel into precise internal locations. Like inside your knee or even your spinal cord, or maybe even your heart, eh you get the picture. Once the cells are laid, they begin to grow and grow and grow. They find their way to integrate in with your body and heal itself. This is really not just a medical innovation, I think it’s the reprogramming of recovery itself.

At the core of this miracle is bio-ink which is a gel-like substance carrying stem cells, collagen, amino acids, and all the scaffolding needed to mimic real tissue. The printer is often inserted through a small incision or a natural orifice (yikes, sorry guys). It slides into the body with robotic precision, armed with imaging sensors that map its environment in real time, like a weird GPS for the human interior that Mrs. Frizzle might’ve had.

Once it reaches it’s target area (whether it’s a torn ligament or a damaged artery) it begins to print. That little guy can build new life in real time. Each deposit is an act of cellular faith, sort of like a scaffold to be filled. It can signal a new beginning for tissue that forgot how to rebuild itself.

If you’ve read The First Real Memory Implant Just Happened, this is its biological cousin. Just one shapes thought while the other shapes flesh.

Who’s Leading the Charge

A few key names are at the forefront of course.

Carnegie Mellon University, whose “FRESH” printing technique allows for soft, flexible structures to be printed directly in place is a big name to keep an eye on in this creation. Harvard’s Wyss Institute, which focuses on synthetic organs and living scaffolds is another worth mentioning.

Prellis Biologics is a biotech startup working on vascular structures for printed tissues that might just blow up into something big if it works. Oh, and of course, DARPA, the U.S. military’s advanced research agency, which sees potential for battlefield medicine that could make the future look like printing a patch, saving a life, and carrying on into battle. DARPA likes the idea of a future where a wounded soldier doesn’t need evacuation and instead, a medic kneels beside them and prints new tissue right there in the field.

While it sounds completely insane, or like one of my crazy books I read, it’s actually being tested in real-time.

Under traditional medicine, you might face months of rehab and a thick scar. But now, a flexible printer could slide into your body, patch what’s broken, and be out before the anesthesia wears off. These new tissues heal faster and more naturally because they’re printed in exactly the right spot with biological cues your body actually understands. Our current method is a little rougher than this, placing the organ in the general area it should be then letting the body heal itself.

For those suffering on a daily basis from arthritis, ulcers, stroke damage, or spinal trauma, this could be life reprinted. We once carefully coaxed healing into our systems, but now, we’ll find ways to whisper it into code then into our cells.

The FDA has approved early versions of this technology for clinical trials, but the path from lab to hospital is as delicate as the tissues we’re printing.

What Could Go Wrong

Ahh, the part I’m extra good at in life: looking for all the things that could go wrong. I mean, damn, am I good at catastrophizing life. I’d like to blame my trauma, but eh, could very well just be me, my grandma does the same thing. Like all great leaps, this one could stumble and fall if the printed tissue doesn’t receive enough blood flow, which could lead to it dying.

If the bio-ink ratio is off, it could lead to scar tissue, or worse, promote tumor growth, which would obviously be very bad.

If immune responses aren’t understood well enough either, rejection becomes a possibility. Think of it like baking sourdough (because that’s the best metaphor I can come up with at the moment, sorry), the yeast must be alive, and the dough must be folded gently. You’ve got to watch the temperature and make sure the bread doesn’t proof at the wrong time, etc etc. The stakes are higher here, yeah, of course, but it’s just an analogy, and I’m just a sommelier.

We’ve learned, through science and bread as well, that timing, temperature, and technique means everything.

The Good

That’s the obvious, wild frontier is growing organs next. We’re talking about entire hearts, kidneys, and lungs printed and personalized, so you never have to pray for a donor match again. The dream is a hospital where your own cells are harvested, printed into the organ you need, and installed with minimal invasion. No waiting lists or immune-suppressant drugs that you have to take for the rest of your life, and no second-hand life.

Already, researchers are printing vascular systems, like the veins and arteries that once made organs unprintable. Now they’re finding ways to make blood flow where once there was only scaffold. We’re ten years away (maybe less, maybe more, depends on how all these tests go) from viable printed organs. That’s not a rumor I’m spreading after hanging by the waterjug at work either, that’s in peer-reviewed journals.

This isn’t just good for people either, it’s good for animals, too. Many cosmetic companies rely on animal skin for testing, but with printable human skin now viable, cruelty can finally bow a little bit to science. Even pharmaceutical companies could shift their protocols as the lines between synthetic and biological blur, lab-grown ethics may finally eclipse lab-grown cruelty.

The Human Body at Home

If you’re like me, you probably first learned anatomy from a board game. Operation…that little buzzing game of tweezers and giggles, is a surprisingly charming way to bring this topic to light with kids or friends.

No, it won’t teach you bio-ink ratios, but it reminds us of one thing: healing takes precision.
Operation Board Game on Amazon

You never know where a little plastic wishbone might lead and this is also super fun to break out after you’ve had too much Chianti and are with some friends or a drunk husband.

Watching the Future Arrive

I write about science not because I am a scientist, but because I’m constantly in awe of what people in the world are doing and working on. I absolutely love to dream about the future and what it might bring.

This isn’t the end of the body as we know it, but a re-beginning, and I’m excited to see where it leads us all.

References

Gao, Z., Hu, D., Li, X., Xu, Y., & other authors. (2024). Imaging-guided in vivo 3D bioprinting of functional materials in deep tissue via focused ultrasound. Science, 385(6694), 539–546. https://doi.org/10.1126/science.adt0293

California Institute of Technology. (2024, August 2). Ultrasound-guided printing inside the body could offer new treatments. EurekAlert!. https://www.eurekalert.org/news-releases/1082646

3D Printing Industry. (2024, August 2). Using ultrasound to print inside the body: Caltech unveils Deep Tissue In Vivo Sound Printing technique. https://3dprintingindustry.com/news/using-ultrasound-to-print-inside-the-body-caltech-unveils-deep-tissue-in-vivo-sound-printing-technique-239487/

IEEE Spectrum. (2024, August 5). Bioprinting inside the body is now possible with sound. https://spectrum.ieee.org/bioprinting-inside-the-body