Synthetic Cells: The Next Bioengineering Frontier

Summary

Short Wave — “Synthetic Cells: The Next Bioengineering Frontier”

NPR, October 13, 2025 | Host: Regina Barber | Guests: Kate Ademala (University of Minnesota), Drew Endy (Stanford University)

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Episode Overview

This episode explores the rapidly advancing field of synthetic biology—specifically, the quest to build a living cell from non-living components. Host Regina Barber is joined by synthetic cell pioneers Kate Ademala and Drew Endy. Together, they demystify why building synthetic cells is so challenging, what it might enable for bioengineering and medicine, and how approaching life from scratch opens up new ways to understand biology at the most fundamental level. The conversation is colorful, accessible, and full of creative analogies, making the fascinating frontier of synthetic cells understandable—and exciting.

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Key Discussion Points & Insights

1. What Makes Living Cells So Complex?

• Vast Numbers, Small Scales
  • Humans contain around 30 trillion cells—far outnumbering the stars in the Milky Way (00:25).
  • Despite centuries of study, we still lack a full “ingredient list” for even the simplest living cell.
• The “Black Box” of Biology
  • “There is no natural living cell that we can have a full chemical ingredient list for… it's kind of like a black box.”
    — Kate Ademala (00:50)
  • Complexity means a trial-and-error approach (“tinker and test”) dominates current bioengineering efforts (01:15).

2. The Synthetic Cell Dream: Goals and Possibilities

• Why Build Synthetic Cells?
  • Synthetic cells could be programmed to:
    • Enable new cancer therapies
    • Manufacture medicines more efficiently
    • Support green energy projects (artificial photosynthesis/fuels)
      (02:03)
  • The field promises fundamental scientific insights and practical applications.
• Still Mystery at the Core
  • “As the engineers learn how to construct cells, there will still be profound mysteries… that will lurk underneath.”
    — Drew Endy (02:30)
• Turning Science into Engineering
  • Building cells is transitioning from a speculative project to a systematic, engineering-driven enterprise.
  • “Building cells from scratch is no longer a research project. It's now an engine...”
    — Drew Endy (02:47)

3. Visualizing the Cell: A Walkthrough

• “Building as a Cell” Analogy (Discussion: 04:25–07:31)
  • To understand a cell’s complexity, imagine scaling it up to the size of a large building (100 meters):
    • Proteins become the size of basketballs.
    • Ribosomes (the protein-makers) are person-sized.
    • DNA would be kilometers long, packed and coiled through the “building.”
    • Cells are packed almost like a hoarder’s bookstore, with 20–40% filled with “stuff” (molecules).
  • “Imagine a bookstore that's 50% full of books and you could just barely move through it…”
    — Drew Endy (06:26)
  • Everything inside is in constant rapid motion—the “basketball”-sized protein zips through the full “building” in a second.
  • This level of chaotic, dynamic activity is what makes cellular replication so mysterious and hard to model.

4. Building a Cell from Scratch: The Synthetic Approach

• Engineering a Predictable Bookstore
  • “The synthetic cell would be like a bookstore that you're filling one shelf at a time... Because we built it from the parts that we know about and we know what they're supposed to be doing, then we can actually understand and most importantly, predict where they go.”
    — Kate Ademala (07:43)
  • Control, predictability, and understanding are core motivations.
• Bottom-Up vs. Top-Down Approaches (08:40–12:36)
  • Three Lineages in Synthetic Biology:
    1. Origins of Life Researchers: Recreating early cells to study life's beginnings.
    2. Minimal Genomes: Stripping existing cells down to basics for insight into essential functions.
    3. Engineers: Building new systems from molecular parts—now capable of assembling complex gene circuits (09:08–09:59).
  • Past “synthetic cells” often relied on “top-down” genetic swaps—using a living host cell. True synthetic cells involve assembling from nonliving components—a “bottom up” process that offers full creative control.
  • “When Kate's talking about building a cell from scratch, we are not subject to [lineage] constraint because she gets to choose every block of DNA that goes into that system.”
    — Drew Endy (11:01)
  • Analogy to LEGO or Minecraft: leaving an existing world (“lineage land”) to create entirely new biology from scratch (12:00–12:36).

5. How Close Are We? What Counts as Synthetic Life?

• Defining Life Itself is Tricky
  • “There is no good definition of life… if it quacks like a cell, moves like a cell, then it's starting to be a cell-like entity, and that's where the field is.”
    — Kate Ademala (13:04)
  • Current synthetic systems perform many cell-like functions, but aren’t as complex as natural cells (13:04–13:29).
  • Progress is rapid and ongoing; this isn’t just science fiction or a dream for future decades.

6. Why It Matters

• Delivering the Promise of Bioengineering
  • “Building a cell from scratch is absolutely essential to realize the promise of bioengineering… we cannot keep running our economy on petrochemicals, on oil. We have to build more equitable economy. We have to really understand biology on this very fundamental molecular level. And all those things will not happen unless we truly understand this very basic building block, which is a cell.”
    — Kate Ademala (13:46)
  • Only by building and understanding cells at the fundamental level can science and engineering deliver on promises of greener, more sustainable, and equitable products and industries.

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Notable Quotes & Memorable Moments

• “Biology, from the chemical point of view, is actually really boring... it uses only 22 amino acids out of hundreds possible... We want to do things that biology never bothered doing.”
  — Kate Ademala (01:41)
• On the “cell as hoarder" analogy:
  “It's like a hoarder of molecules.” — Drew Endy (06:26)
  “It's like those terrible bookstores… get organized!” — Regina Barber (06:28)
• “I would love for somebody to build a building that's a cell…” — Drew Endy (05:22)
• On possibility and creativity:
  “Every time you build something, you're limiting the possibilities because you have to make choices. And biology has been making those choices for over 3 billion years… we're now revisiting all those alternatives. That's the fascinating part...”
  — Kate Ademala (12:36)

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Timestamps for Key Segments

• [00:25] – Introduction: The sheer number and complexity of cells
• [01:01] – Introducing Kate Ademala; the black box of cellular biology
• [01:41] – Amino acids, biological limitations, and synthetic possibilities
• [02:03] – Potential societal applications of synthetic cells
• [04:25] – Visualizing a cell as a giant building; scaling up biology
• [07:43] – The engineered “inventory” of a synthetic cell
• [08:40] – Historical groups and approaches in synthetic biology
• [10:21] – The distinction between synthetic genomes and synthetic cells
• [11:01] – Escaping lineage: bottom-up synthetic cellular engineering
• [12:36] – Revisiting alternative biological solutions
• [13:04] – How close are we? What qualifies as life?
• [13:46] – Why this work matters for the future of science, engineering, and society

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Tone and Language

The episode blends scientific rigor with playful analogies and an encouraging, open-minded tone. Both guests and the host frequently use metaphors and pop culture references (e.g., bookstores, LEGOs, Minecraft) to clarify concepts, making the topic approachable for all listeners.

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This summary captures the major themes, technical insights, and quotable moments from an engaging, thought-provoking episode that welcomes everyone into the vanguard of what might soon be a new era in biology—and engineering.

Transcript

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[Regina Barber]

There are more cells in your body than there are stars in the Milky Way galaxy. Our galaxy has a couple hundred billion stars. And inside me and you, each of US has around 30 trillion human cells. 30 trillion cells are the fundamental building blocks of life. But that doesn't mean they're simple. Biology still doesn't have a full picture of how exactly a living cell works.

[Kate Ademala]

There is no natural living cell that we can have a full chemical ingredient list for. And we don't know all the genes, even in the simplest cell. So it's really kind of like a black box.

[Regina Barber]

That's Kate Ademala, a biological engineer at the University of Minnesota. She wants to do what only nature has done, build a cell from scratch. A synthetic cell that replicates itself, but was made in a lab.

[Drew Endy]

All of bioengineering right now is Edisonian tinker and test. Tinker and test. We don't know when we go to make something happen if it'll work or not until we build it and test it.

[Regina Barber]

Drew Endy is an engineer at Stanford University and part of a community co founded by Kate called Build a Cell. This is an international group of researchers with the same goal to build a cell from the bottom up, piece by biological piece.

[Kate Ademala]

If you look at the entirety of biology, it actually, and I'm going to piss off a lot of biologists by saying that, but biology from the chemical point of view is actually really boring. It uses only 22amino acids out of hundreds possible amino acids. And that's another motivation for engineering cells from scratch, is we want to be able to invent things, to do things that biology never bothered doing.

[Regina Barber]

If scientists can create cells, they can be programmed to do all sorts of things. And scientists have touted the dream of synthetic cells as a new solution to the world's problems. Synthetic cells could be programmed to act as part of new cancer therapies, can create new medicines easier and cheaper. They could even be made to produce artificial photo to help with green energy projects. And somehow that would just be the beginning.

[Drew Endy]

I truly believe that as the engineers learn how to construct cells, there will still be profound mysteries in biology and life that will lurk underneath.

[Regina Barber]

Synthetic biology is not a reality yet, but it's on the horizon. Especially now that engineers have taken the helm.

[Drew Endy]

Building cells from scratch is no longer a research project. It's now an engine, which means we can plan to do it and anticipate deadlines. And it's right in front of us.

[Regina Barber]

Today on the show DIY Cells. We dive into what it would look like to be inside of a cell, why scientists are bothering with making a cell from scratch, and how engineers are leading the field. I'm Regina Barber and you're listening to Shortwave, the science podcast.

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[Regina Barber]

Okay, Drew, before we can build a cell, we have to understand them. And I've always had a really hard time visualizing, like, what's happening inside of a cell, but you have this, like, really cool way to think of them, like, as a building, right?

[Drew Endy]

Yeah. The question that motivates thinking about a cell as a building is are cells intrinsically complicated or are they just, do they just appear to be complicated because they're so darn tiny and, and so we can't see what's going on? And so as a mental exercise, imagine taking a cell that might be a millionth of a meter across, a micron, super tiny. And now imagine making it magically 100 meters long.

[Regina Barber]

Scale it up.

[Drew Endy]

So we're going to scale up, we're going to multiply the size of a cell by a factor of 100 million with a magic wand. You know, the cell's not this solid object. It's an object comprised of smaller objects, molecules. And so now we can, at this scale of 100 meter cell, a building size cell. By the way, I would love for somebody to build a building that's a cell.

[Regina Barber]

Yeah. And just have like, we could all like doing the things inside the cell and like moving things.

[Kate Ademala]

Totally.

[Drew Endy]

Or like Roombas or whatever. But so a protein inside this Building size cell is going to be about as big as a basketball. And then the thing that makes proteins, the ribosome, this molecular machine that makes proteins from genetic instructions, that's going to be about as tall as a person. And then the DNA inside cells is DNA, the genome, the genetic instructions. That DNA for our cell is going to go back and forth across the cell over a thousand times, right? If the building's 100 meters long, the DNA is going to be kilometers long, and it's going to be coiled up and wrapped up and packed inside the cell. And then another thing that shows up is if you're inside a cell in this building, the buildings can be packed maybe 20% to 40% of stuff.

[Kate Ademala]

Wow.

[Drew Endy]

It's like a hoarder of molecules.

[Regina Barber]

It's like those terrible bookstores, you know, where they have those piles of books and you're like, get organized. Like that place.

[Drew Endy]

Imagine a book. Imagine a bookstore that's 50% full of books almost, and you could just barely move through it. Now, there's one more wrinkle that blows my mind. The molecules inside the cell are moving. They're not fixed in one position, and they're moving spontaneously because the molecules are free to move due to the energy of the system. And so that protein, that's a little basketball in this big building is moving so fast, it's able to go through the entire building within a second. And so that's, that's what's incredibly interesting to me when we start to think about how are these systems working? How are these cells making other cells? How are they alive? If we could see it and follow it in real time, I'm 100% certain we could figure it out. It's just that it's moving so fast and it's so darn tiny, we haven't been able to follow it exactly right yet.

[Regina Barber]

Well, see, this is, this is where we get to the next question, Kate, is that what if we could build a cell so that we could understand it better? So, like, how would you describe the synthetic cell you're building towards?

[Kate Ademala]

The synthetic cell would be like a bookstore that you're filling one shelf at a time, you know what sections you want. And using Drew's analogy, you're filling it to have all the books that you're interested in, but because you're putting them in, you know where they go, you know what books you put in, and you know where they're supposed to move. It's still tiny. But because we built it from the parts that we know about and we know what they're supposed to be doing, then we can actually understand and most importantly, predict where they go. Because it's not just about understanding where they used to go. It's about predicting where they are going to go, where you do something. And that would be a synthetic cell. It would be a bookstore with a really good inventory. Because we know what goes into a synthetic cell and we can grow it. And that's the most fascinating to me as an engineer, is I don't want to just build something complex. I actually want to know why it works the way it does.

[Regina Barber]

Okay, so Drew, when did the idea of building a cell, a synthetic cell, start to seem possible? Like, what's the history here?

[Drew Endy]

Yeah, I'll give my version. And then I beg Kate to chime in too. I see there's three different factions or groups that we're interested in, are interested in the topic. One are the folks who are interested in the origins of life. Where does life come from? And so that tribe, if you will, or group has been working towards building cells for a very long time. Then there's another group that's been taking natural cells and whittling them down to remove all the extra pieces they can and building synthetic genomes with just the stuff needed to keep it going and making a type of minimal synthetic cell starting from natural cells. And that's been going on for a couple decades. And then over the last Decade plus, the third group, the engineers, are arriving, and genetic engineering is 50 years old. That starts by moving small numbers of genes around. By 2010 or so, the people from that group are getting good enough that they can begin to put together 30 or 40 gene systems, making sophisticated biochemical pathways in natural cells.

[Regina Barber]

Okay, so, Kate, I was going to ask you about that. That's more of the bottom up approach. That's what was going on in 2010 when, like Drew just said, this group of scientists, they like, quote, built a genome from scratch and used it to control a cell. Only the genome was synthetic. Right. Like, how is build a cel your effort different and maybe even like improving on that research?

[Kate Ademala]

The build a cell is different than just the construction of a cell with synthetic genome because there was a living recipient cell that was the recipient of that genome transplantation. So it wasn't building a cell from nonliving components. We learned a ton in the last decade, decade and a half now about how molecules come together to drive those very basic processes of biology. So now we're finally starting to be able to conceptualize how we would go about not just making a synthetic genome, but booting up the whole thing from scratch. And that gives us this full operational control over every element of it.

[Regina Barber]

Yeah.

[Drew Endy]

There's a subtle point in what Kate's describing that's central to building cells from scratch, which is we're not constrained to any one natural cell. So all of life on earth in nature descends or derives from the life that's already here. That's lineage. Right. We come from our parents and so on. If you're minimizing a natural cell, you're operating within the context of lineage. And if you wanted to understand it, you can take this top down approach, as you say, which is to begin to remove pieces bit by bit and see if it's still alive. I think of it as whittling or, you know, sculpting a block of marble. You're removing everything that's not needed. When Kate's talking about building a cell from scratch, we are not subject to that constraint because she gets to choose every block of DNA that goes into that system.

[Regina Barber]

And that's the bottom up method.

[Drew Endy]

That's the bottom up, exactly. The way I think about it metaphorically, is I imagine we're all part of this giant world called lineage land. And if we leave that continent or world, go to a new world, you know, we. We just get to build new things. And it's. It's a very. It's a very subtle mental shift.

[Kate Ademala]

Yeah.

[Regina Barber]

It makes me think of the Lego movie of like the different lands.

[Kate Ademala]

Yes.

[Regina Barber]

And like, one's already built versus like, if you just go to like, an open area or like in Minecraft where you go into somebody's like, realm already that already exists, versus, like, going to your realm where you can build something. Kate's like, yes, yes.

[Kate Ademala]

Every time you build something, you're limiting the possibilities because you have to make choices. And biology has been making those choices for over 3 billion years. So we did reject a lot of possible alternatives, and we're now revisiting all those alternatives. That's the fascinating part of it, is we can see what else can be done with biological parts.

[Regina Barber]

So where is the field right now? Like, how close are you to creating synthetic life?

[Kate Ademala]

It's very difficult for me to answer that because there is no good definition of life. But we're getting to the point where if it quacks like a cell, moves like a cell, then it's starting to be a cell like entity, and that's where the field is. We don't have the complexity that approaches the natural biological cell. But we have systems that can perform all the functions of a cell.

[Drew Endy]

This is not something that's decades into the future. This is something that's a very active field making progress in real time.

[Regina Barber]

Yeah, last question. There are many scientists that are working towards this goal, including both of you. Why is building a cell from scratch so important?

[Kate Ademala]

Building a cell from scratch is absolutely essential to realize the promise of bioengineering. When the field was started by Drew and others, they made huge promises. They said, we'll be able to make things with biology, will be able to have this green economy. Those promises have to be realized because the way the world is going right now, we cannot keep running our economy on petrochemicals, on oil. We have to build more equitable economy. And we have to really understand biology on this very fundamental molecular level. And all those things will not happen unless we truly understand this very basic building block, which is a cell. And really, I believe we will not be able to understand a complex natural cell unless we can actually build it.

[Regina Barber]

Kate Drew, thank you so much for talking to me today about synthetic cells. I learned a lot. Thank you so much.

[Drew Endy]

Thanks for having us.

[Kate Ademala]

Thank you. It was a pleasure.

[Regina Barber]

Shortwavers, thank you for listening. And if you want to help us out, follow us on the NPR app or whatever other podcasting app you use. This episode was Produced by Burleigh McCoy, edited by our showrunner Rebecca Ramirez, and fact checked by Tyler Jones. The audio engineer was Jimmy Keeley, Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave from n.

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