90.9 WBUR - Boston's NPR news station
Top Stories:
PLEDGE NOW
Here and Now with Robin Young
Public radio's live
midday news program
With sponsorship from
Mathworks - Accelerating the pace of engineering and science
Accelerating the pace
of engineering and science

Building Tiny Human Organs With 3-D Printing

Dr. Sangeeta Bhatia has big ideas about her work with tiny organs. Using 3-D printing and human cells, she’s created a miniature human livers in her lab at MIT that can be used for testing drugs.

Dr. Bhatia is part of a bio-engineering revolution that is transforming the field of medicine. She tells Here & Now’s host Jeremy Hobson that her goal is to scale up the size of the micro-liver so it can be used as an alternative to human-to-human liver transplants.

Interview Highlights: Dr. Sangeeta Bhatia

On what her team has accomplished thus far

“We have built little human livers already that we can grow that contain about a million cells in animal experiments that we would then like to take to humans someday.”

“The livers we’ve built so far look a lot like a soft contact lens. We call them our contact lens livers, and they contain about a million liver cells. Your liver actually has about a hundred billion liver cells, so they need to be about a thousand times bigger.”

On how her team creates miniature human livers

“Building livers, you could use lots of different fabrication tools. So some of the older ones we used were simple molding strategies. The newer technologies that you’re thinking about are what we call additive fabrication technologies. So basically you build parts layer by layer, and you can do that several ways. You could do it with light, so you could use a light-sensitive material, and shine a pattern in every layer and end up with a 3-D part. You could have a powder and you could print glue, and then the glue could build a 3-D part out of a sort of vat of powder.”

“It’s different for every tissue. For the liver, what’s so interesting is that there’s no stem cell in the liver, so the normal liver actually can regenerate. It’s one of the only organs in the human body that can do this, and we’ve known this since the time of Greek mythology. There’s actually a wonderful old myth about Prometheus, who stole the fire from the gods, and his punishment was than an eagle, which was Zeus, would eat his liver every day, and every day, the liver would grow back. And so in the liver field, since that time, since the 8th century B.C., we knew the liver could regenerate and it doesn’t need a stem cell, and in fact, if we cut 50 percent of the liver out, it’ll be back in two weeks.”

On challenges her team faces

“At this point, we have so many fewer organs than we need that we would like to augment the supply, and ultimately, we would love to replace them, but I think we’re really a long way from that.”

“The biggest challenge is, for us, for building implantable organs, as I mentioned, are scale, right? So we have a million cells and we probably need to get to a billion or 10 billion. An interesting opportunity is actually not just thinking about building organs for patients, but actually building little tiny organs that you could do drug screening on. And this is a way that the fabrication technologies are really helpful, so we’ve made little micro livers. They’re about the size of the pin of a needle, and they allow us to do drug testing to test if drugs would be safe when they got into humans.”

Guest

  • Dr. Sangeeta Bhatia, director of the Laboratory for Multiscale Regenerative Technologies at MIT.

Transcript

JEREMY HOBSON, HOST:

At a conference of the American Diabetes Association over the weekend, researchers said more than 2,000 people have already been helped by a bionic pancreas. It uses a smartphone, a glucose monitor and an insulin pump to control blood sugar levels without finger pricks.

And if a bionic pancreas sounds pretty sci-fi and futuristic, what about a 3-D printed liver? That is being worked on as well by researchers at MIT. Sangeeta Bhatia's one of them. She's director of the Laboratory for Multiscale Regenerative Technologies at MIT. And she's with us in the studio. Welcome to HERE AND NOW.

SANGEETA BHATIA: Thanks. Hi, Jeremy.

HOBSON: So in the past few years, we've heard about using human stem cells and 3-D printing to create body parts. There was a 2-year-old who received a synthetic trachea, an 18-month-old who was given 3-D printed splints to support his weak windpipe. How far away are we from having a 3-D printed liver or heart?

BHATIA: Well, so this field that you're referring to is one that we call regenerative medicine. And it grew out of a field that started in the '90s called tissue engineering where we were trying to take cells and put them together with scaffolding materials and build organs.

And some of the organs that you're referring to are things that we think of as almost the simpler organs. They're more structural. Once you get into more complicated tissues that have coordinated functions, like the heart having to beat or the liver, which has about 500 functions, then we're getting into more early-stage research.

HOBSON: Becomes more complicated.

BHATIA: Exactly.

HOBSON: OK, but you're working on it. So is it something that could happen?

BHATIA: Yes, absolutely. So we have built little human livers already that we can grow that contain about a million cells in animal experiments that we would then like to take to humans someday.

HOBSON: You say little human livers. We're talking about livers that would fit in a mouse.

BHATIA: Exactly. And so the livers we've built so far look a lot like a soft contact lens. We call them our contact lens livers. And they contain about a million liver cells. Your liver actually has about a hundred billion liver cells. So they need to be about a thousand times bigger.

HOBSON: Well, how do you do that exactly? How do you 3-D print even a tiny liver?

BHATIA: So building livers - you could use lots of different fabrication tools. So some of the older ones that we used were simple molding strategies. The newer technologies that you're thinking about are what we call additive fabrication technologies. So basically you build parts layer by layer.

And you can do that several ways. You could do it with light. So you could have a light-sensitive material and shine a pattern in every layer and end up with a 3-D part. You could have a powder and you could print glue, and then the glue could build a 3-D part out of sort of a vat of powder.

HOBSON: So how would you, for example, build something that then could do what you say is so difficult, which is to have a heart that beats?

BHATIA: So the sort of the tricky bit is not so much the material printing, which I was just talking about, but the living cells. So you need to get human cells, and then you need them to be happy outside of the body. And so inside the body they're happy because they have, what we call, a microenvironment that keeps them that way.

And so you basically need to kind of re-create that in your printed parts that they will do the function that you're interested in. So if you're a heart cell, you care about it contracting. If you're a liver cell, you care about it metabolizing the drugs that you take. If you're a beta cell, which is in the pancreas, you care about making insulin. So depending on what tissue it is, you're trying to re-create the environment so that the cell will do the function you're trying to exploit.

HOBSON: Now, when you say get human cells, how easy is that?

BHATIA: So it's different for every tissue. For the liver, what's so interesting is that there's no stem cell in the liver. So the normal liver actually can regenerate. It's one of the only organs in the human body that can do this, and we've known this since the time of Greek mythology.

There's actually a wonderful old myth about Prometheus, who stole the fire from the gods. And his punishment was that an eagle, which was Zeus, would eat his liver every day. And every day the liver would grow back. And so in the liver field we say since that time, since the 8th Century B.C., we knew the liver could regenerate, and it doesn't need a stem cell.

And in fact, if we cut 50 percent of the liver out, it'll be back in two weeks. So that's an amazing capacity. We just need a few liver cells and then we think we could grow that 10 billion that we need. In other organs, there is not this capacity. And in those cases, you probably need a stem cell to grow the tissue of interest.

HOBSON: Some people have ethical issues with this kind of technology - 3-D printing organs, if that ends up happening in a big way - that you're messing with mother nature. This could lead to human cloning. How do you respond to that kind of criticism?

BHATIA: So I think that new technology development is always fraught with controversy. One thing that's interesting about this sort of messing with human nature argument is that if you go back historically to transplantation, the same thing was said then. So the earliest transplants were done in the '50s, and these were twins where one kidney was transplanted into another. And it was the same idea - you're messing with human nature. You're taking a human life that was destined to end and rescuing that person with an organ from someone else.

Really it's just an extension of the same argument. But now transplantation is no longer controversial. And I see this as really an extension of transplantation. Instead of taking cells in the organ that they grew up in, you're taking them out and putting them in a new scaffolding.

HOBSON: Well, and it brings up a question, which is, do you see this replacing traditional organ transplants at some point?

BHATIA: At this point we have so many fewer organs than we need...

HOBSON: Yeah.

BHATIA: ...That we'd like to augment the supply. And ultimately we would like to replace them. But I think we're really a long way from that.

HOBSON: Still a long way away.

BHATIA: Still a long way away.

HOBSON: What are the biggest challenges at this point for you?

BHATIA: So the biggest challenges for us for building implantable organs, as I mentioned, are scale, right? So we have a million cells, and we need to probably get to a billion or 10 billion. An interesting opportunity is actually not just thinking about building organs for patients, but actually building little tiny organs that you could do drug screening on.

And this is a way that the fabrication technologies are really helpful. So we've made little microlivers. They're about the size of the pin of a needle. And they allow us to do drug testing to test if drugs would be safe when they got into humans.

HOBSON: When you look forward and think of your dream scenario, if all of your work comes to fruition, what will be the result?

BHATIA: So we would like to print an organ that is about 10 percent the size of a normal liver, which we think can support a large number of patients. And what we would do is we would implant them, not where the liver is, actually in the belly, in the peritoneum. And they would hook up to the blood vessel of that person, and then they wouldn't need a transplant. That's the goal.

HOBSON: Sangeeta Bhatia is a doctor and researcher, director of the Laboratory for Multiscale Regenerative Technologies at MIT. Sangeeta, thank you very much.

BHATIA: Thank you. Transcript provided by NPR, Copyright NPR.


Please follow our community rules when engaging in comment discussion on this site.
Robin and Jeremy

Robin Young and Jeremy Hobson host Here & Now, a live two-hour production of NPR and WBUR Boston.

November 24 24 Comments

Jose Antonio Vargas May Soon Become Documented Immigrant

The activist and journalist is one of the undocumented immigrants expected to receive protection from deportation.

November 24 7 Comments

Doctor: Hard-To-Abuse Painkillers Won’t Fix Overdose Crisis

There's a question of whether the new technology of addictive painkillers will help stem the epidemic or help fuel it.

November 21 5 Comments

Students Protest University Of California Tuition Hikes

In spite of protests on University of California campuses, the board voted to hike tuitions by about 5 percent every year for the next five years.

November 20 3 Comments

The Man Behind ‘Mockingjay’

Francis Lawrence describes the rewards and challenges of bringing "The Hunger Games" books to the screen.