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Ask-A-Scientist Podcast E6: Dr. Junjie Yao, glassfrogs researcher

Listen to our podcast episode or read the transcript below featuring Dr. Junjie Yao, glassfrogs researcher at Duke University, as we talk about camouflaging tricks by magical creatures, engineering biology and ChatGPT’s poetry.

“We’re lucky that we do what we love and we love what we do.”

“You have a problem to solve and you try to find the best engineering solution.” 

“What is the chance that you will have a good idea when you are taking a shower?”

Tanya: Hi everyone. Welcome to Ask a Scientist, a Science Journal for Kids podcast where we explore what it’s like to be a scientific researcher. I am Tanya Dimitrova and I am here with my co-host – Dr. Miranda Willson.

Miranda: Hey there.

T: Our guest today is Dr. Junjie Yao. He teaches Biomedical Engineering at Duke University. He did his Bachelor’s and Master’s degrees at Tsinghua University in Beijing, China, and his Ph.D. at Washington University in St. Louis, the United States.

Junjie’s work focuses on a technology called photoacoustic tomography and how it can be used to diagnose or even treat brain diseases like cancer. He also works with some tiny and unusual animals from South America called glassfrogs. (They’re called this way not because they shatter when they hit the floor but because they are transparent!) Junjie and his colleagues recently discovered that these frogs make themselves transparent while they sleep by hiding their red blood cells inside their liver! 

This research was published in the journal Science and here at SJK we recently adapted it for school students. Today, we will talk with Junjie about his work but we will also get to know – at least a little bit – the person behind the professional scientist. Hello Junjie, welcome to the podcast!

Junjie: Hi there, hi everybody. Thanks for having me. 

M: Your current research is at the cutting edge of biomedical science. But we’re going to start from the time you were a student yourself. What kind of school did you go to and what subjects did you take? 

J: I am from China, from a tiny small town. Funny thing is that town was so small it doesn’t even have its own name. It’s called 10 miles because it is actually 10 miles from another bigger town. So that’s where I was from. Of course I worked hard. I went to high school and I went to Tsinghua University in Beijing. That’s probably the best, I should say, science and technology university in China. My major was biomedical engineering and I was doing biomedical engineering in college, in my graduate school and now I’m teaching biomedical engineering at Duke University. So you can say I’m a medical engineer from the beginning. 

T: Would you say that the academic experience in a Chinese university is very different from, say, the United States?

J: When I came here to the States, I would say that there is a cultural difference. Here people, the teaching, the education are more focused on inspirational discussion and encourage students to be more creative and independent. I think that makes a lot of difference down the road for students to develop their own interests. 

T: And students can say ‘no’ to their professor, right?

J: They do that all the time. [laughter] I teach both undergraduate and graduate students and I can tell you, my first couple years of teaching were terrible! Because I was challenged so many times, so often in class. And sometimes I was not so prepared and I felt so embarrassed. But, you know, as I get better, I can take the questions better. And I do appreciate the students – their encouragement, their challenge, and their engagement in the class. I even give them bonus credits if they challenge. 

T: When you first came to the states for your PhD how old were you?

J: Let me do a quick math… I was 23. 

T: What was this transition like? Did you have any significant challenges?

J: The shock I had when I first came here was probably from the language. I remember that I came off the plane in Chicago. I transferred there. And I couldn’t even make a phone call because I couldn’t make a meaningful conversation with people working there at the airport. And I regretted it right away you know… Why did I come here? Should I just buy another ticket and fly back? But that was quickly overcome after I made friends with local students and got help from my professors. And of course, I work in a fantastic lab at Washington University and the people there are really supportive. So you know, I quickly overcame that language barrier.

Photoacoustic microscopy image of glassfrog blood vessels
(Credit: Yao lab)

Miranda: Let’s talk a bit about your field: biomedical engineering. It sounds simultaneously futuristic, sci-fi, and very complex. What’s good about it? What do you like about it? What draws you to it specifically?

J: That’s a good question. I teach students here at Duke and I think a common question people ask is ‘What is biomedical engineering?’ 

T: Yeah, let’s start there.

J: It’s a combination of all the exciting stuff! Basically, we’re using engineering tools to study human biology. 

T: We are always interested to know how professional scientists like you manage to balance these different aspects of your work in professional life. On the one hand, you’ve got teaching, writing, doing the actual research, mentoring students. Then on the other, I hope that you actually have time with your family as well. And you have to take care of your health, and you have to sleep. Is it even possible to find the right balance? And and if so, how? 

J: Well, Tanya, that’s a great question. I think the answer to that question is probably very case-by-case-dependent. It also depends on your career status. So I can only speak from my own experience: the life-work balance is a tricky thing for a scientist. I always tell my students, or the potential students, or the potential scientists in the future that this is a kind of a weird job. It’s weird because you do this because you love it. We’re lucky that we do what we love and we love what we do. So that’s really lucky for us as scientists. On the other hand, it’s not like other jobs where you have a clear definition of when you start working and when you come off; where you can go home. So this is almost like a 24-7 type of job. And you always have something in your mind; you always have something you are thinking of; a question you are interested in or you’re puzzled about in the background. This is a job that needs you to be focused and to be concentrated almost constantly. But in the process, you enjoy the discovery, you enjoy the fun of great ideas. And that makes a difference.

T: Do you also sometimes discuss any research questions or hypotheses with your own son? I know you have a young son.

J: Yes, his name is James. You know, I’m busy in my work but whenever I go home, I try to enjoy the family life. So we talk about my work. To be honest, not all my work is so easy to understand but I try to explain my work to him. And I know he tries his best to understand. So there are always overlapping parts that we can both understand and enjoy. So the conversation can always go on.

Sleeping glassfrogs
(Credit: Jesse Delia)

M: So let’s talk a bit more about glassfrogs. Your research, which we adapted for kids, was about glassfrogs and their unique transparency. You and your colleagues discovered that glassfrogs become more transparent when they sleep and that this is primarily due to the storage of their red blood cells inside their livers. Can you tell us a little bit about how you came across these frogs in the first place?

J: OK. My life is focused on developing imaging technology and specifically photoacoustic imaging. This is a technology that uses light to listen to the biomolecules. So it’s a pretty cool process. We convert light into ultrasound. That’s why we can listen to the red blood cells when they are in the blood vessels. 

So we’ve had this technology for years. And we’re developing it to make a better system. And until three years ago, I had never heard of glassfrogs. I didn’t even know there were glassfrogs in South America. So I give credit to my postdoc Carlos. He was a glassfrog expert, he has tremendous experience with glassfrogs. He has a lot of field experience and has caught glassfrogs in the jungles. And we got a chance to talk and he had a pressing need for a technology that can help him study these tiny magic animals. Because at that time, he knew that the glassfrogs could turn transparent when they were sleeping, but he just didn’t know how they did that. 

So we were talking about this very magic animal and after I talked to him, I realized that we had the right technology just two doors down the hallway. It’s sitting in my lab. So that’s the moment that I realized that we could work together and we can help him answer that question. At the same time, we can develop and optimize our imaging technologies to help answer that very specific and important question. And that’s why I invited him to join my lab and we have been colleagues since then. 

So you never know when and where you will have a good idea or good discovery! You just work on your own research 24/7 and you’re prepared, you’re ready to take any new clue or new opportunity. And this is the example that when an opportunity came up and we grabbed it and we made a good discovery.

T: Success is where preparation meets good luck! So we received some questions from students who read your article. We’re going to start with the first one here.

J: I love questions. 

Adyant: Hi, I’m Adyant and I’m a seventh grader from California. So how are glassfrogs’ red blood cells able to perform their basic functions like nutrient and gas transport in the frog if they are stored away during sleep?

J: That’s a great question and that is also part of the reason why this frog is so magical. They have red blood cells almost the same as us. So the red blood cells in our body carry oxygen and also do a gas exchange with the cells and also deliver other nutrients that are needed for metabolism. So in glassfrogs, red blood cells do the exact same thing. So they are required to maintain the basic functions in the tissues. In that sense, it’s crazy that they will store 90% of their red blood cells in their liver when they’re sleeping. That means those red blood cells are useless. They’re not functioning although they are still there. But they are not doing their job and so that means the frogs are basically in near-death mode. So they basically do not consume oxygen, they do not consume nutrients and they are in a minimal metabolism status. So they do not consume as much oxygen becomes they need very little oxygen when they are sleeping. And they can do this for 10 hours a day. And that’s why they can keep their red blood cells in their liver when they’re sleeping – because they don’t use them.

T: I notice you use the word ‘magical’ awfully much for a hardcore scientist and engineer. What’s up with that?

J: That’s because I’m a hardcore fan of Harry Potter. [laughter] I read Harry Potter like multiple times. I know for seven books it’s more than one meaning of a word and I read that multiple times. 

And you know, the more I work on science and especially since I worked with glassfrogs, I think magic is the best way I can describe this small creature. And not because I know they have an invisibility cloak just like Harry Potter does. But also because it’s the way that nature designs the system.

T: We have another question from a student.

Polina: Hi, my name is Polina and I’m a volunteer at Science Journal for Kids and Teens and today I have a few questions for you. Are there any differences between transparency of glass frogs between males and females and different life stages – tadpoles and adults?

J: That’s a great question. Yes. The answer is yes. There is a difference between females and males for the obvious reason that females carry eggs sometimes. So that’s another reason why they want to be more transparent – because they want to be safe. And that’s the difference between a male and a female. Females do have other tricks to play to be better protected. 

And between different developmental stages – you know, frogs, they come from tadpoles so that’s where they have very different body shape. So there are different ways for them to become more transparent. But I wouldn’t say – as tadpoles they are not so transparent because they haven’t developed the way or the same capability to handle red blood cells yet. So they are more transparent when they are adults. 

T: We have another question from Polina.

P: Are there any other amphibians or animals with similar transparent skin adaptations?

J: Glassfrog is probably the only one we know of right now. I’m sure there are others we haven’t discovered yet. And why this is so interesting for us – it’s because glassfrogs are similar to us as they are land animals. 

You will find a lot more transparent creatures (when I say ‘creatures’ it sounds like Harry Potter but what I mean is transparent animals) in the ocean because the water is transparent. So it is much easier for them to develop transparency. On the other hand, land animals are rarely transparent because, you know, the environment is very different, and also we need red blood cells to carry the oxygen to supply the nutrients.

Fun facts about glassfrogs

M: You write that these findings could contribute to the development of treatments for human medical conditions. Tell us more about that.

J: Yes, you know the ultimate goal for us to study glassfrogs is because they are inspirational and they can help us to understand biology and they can help us potentially one day to treat disease. One disease I’d mention is stroke. Basically, that’s where, in most cases, the blood vessels are clotted because the red blood cells conjugate together. And if you think about that, it’s a daily thing for glassfrogs! They do have red blood cells coming together for 10 hours a day and they do not develop clotting at all. And they actually share almost the same red blood cells as we do. So how do they do that trick? We believe glassfrogs do have some chemicals in their bloodstream that can help them from clotting the red blood cells.

T: So you mean if we can synthesize this type of chemical – the one that works on humans – it could be a medication to prevent strokes or to treat strokes with the first sign of the stroke?

J: Exactly, exactly. So that’s the hope. And that’s what we’re working on.

M: We always like to end with a fun Pie-in-the-Sky question. So thinking about all of your interests in biomedical engineering if you had a million dollars, or maybe for you it would need to be a little bit higher, but let’s say you had unlimited funds, what is one burning research question that you would like to try and answer?

J: Okay, first of all, I appreciate your offer. I do want to have unlimited money to do research. [laughter] 

M: You got it!

J: I ask the same questions often time not just to myself but also to my students. I say: ‘Hey, you know, James, if you have unlimited money and resources what would you want to do?’  

So for myself, the answer is: I want to study the brain. So, I want to study the brain in the sense that the brain is such a unique organ: it consumes about 20% of the oxygen and nutrients of the whole body. And imagine, relatively speaking, how small the brain is. It’s very metabolically active and it is so complex. 

So if I had unlimited money, I would work on technologies that can help us to unlock more secrets about the brain. And the fundamental goal is to help us gain knowledge, to develop new even better tools to answer the questions other people may have or the other research topics they come up with.

M: Well, if I find unlimited funds somewhere I’ll pass them your way.

J: Please, send me a check, yeah. [laughter]

T: Junjie, thank you so much for your time today. It was so much fun chatting about glassfrogs, magical creatures, Harry Potter and, by the way, your life as a biomedical engineer. 

J: Thank you very much. Thank you for your time.

M: Did you know that you can directly read one of Junjie’s scientific papers stripped from its complex scientific jargon and made understandable to readers as young as 4th grade in school? The link is in the shownotes. You can also Google its title: How do glassfrogs become transparent? Or directly go to Science Journal for Kids and search for ‘frogs.’

T: Actually, as a bonus today, we’re including some deleted scenes…

J: Most importantly, what is the problem we have? Sometimes it’s a very fundamental problem – something we don’t know. We need to ask a colleague or get help from Google or chatGPT.

Tanya: What?! You use ChatGPT in your work? 

J: All the time. So I can talk about that more. 


Tanya: OK, now, please, tell us more about ChatGPT. We want to hear how you use that in your lab. 

J: So when chatGPT came up, it was a shock, I should say, to people who are not really working on the AI field. How crazy it is, I mean, you can just take your question, your problem, and come up with, I should say, a pretty good solution. So the first response was, I should say, concern from the professors about how students are going to use ChatGPT to do their homework and to do their essays. But eventually, I think everybody made peace with that. You know, students find a way to use ChatGPT in the correct way and professors find a good way to use ChatGPT to do their research.

So what we do in the lab is, you know, ChatGPT is pretty good at summarizing literature. So in many cases, they do a better job than yourself. So you can use that to basically summarize all the previous research you are interested in. And you can use ChatGPT to get you in the right direction of references to do a more in-depth reading. 

And, on top of that, ChatGPT is pretty good at writing. So we actually use ChatGPT to check our writing. Especially for students who are not native speakers and that helps us to get to a good starting point for writing manuscripts. 

And, also, we write poems about our research using ChatGPT. And sometimes we get really good writing about our research. It’s amazing. I highly suggest or recommend everybody to try it. 

M: Can we get a copy of that? Please, we want to hear it.

J: Sure, we have 2,000 of them. 


In the realm of emerald hue,
A creature dwells, unique and true.
A glass frog, a captivating sight,
With translucent skin, a sheer delight.
Its belly, a window to its core,
Revealing organs, nothing more.
Through its skin, the heart beats strong,
A mesmerizing rhythm, a melodious song.
In rainforests of Central and South,
This tiny being, a nature's mouth.
With skin so clear, it does blend,
Evading birds, a crafty trend.
Camouflaged amidst the leaves,
A master of hiding, one believes.
Its legs and belly, transparent grace,
Ensuring safety in its dwelling place.
Oh, glass frog, a mystical creature,
Guardian of the forest's hidden feature.
In arboreal realms, you dwell,
A secret world only you can tell.
A quarter's size, yet full of might,
You vocalize your presence at night.
But beware, for trespassers beware,
Underneath the clear skin, a warning glare.
So let us admire this jewel of the wild,
The glass frog, nature's splendid child.
A testament to beauty and adaptation,
A wonder deserving of our fascination.

Read by: Karen Watts 

T: That’s all for today. This podcast was produced with help from our research assistants Natalia Torres Behar, and students Adyant Bhavsar and Polina Symonenko. Sound engineer Maria Mihailova and hosts Miranda Willson and me, Tanya Dimitrova. Thank you for listening. Subscribe to this podcast to receive notifications about the next episode of Science Journal for Kids’ Ask-a-Scientist. Till then.

All glassfrogs image credit: Yao lab

Title photo: Yao lab

You can read the adapted article here:

How do glassfrogs become transparent?

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