The Life Scientific: Dame Pratibha Gai

0:00This BBC podcast is supported by ads outside the UK.

0:30Dame Pratibha Gai:at Whole Foods Market. Ask yourself, what are your best people spending their time on right now? Expense reports, receipt chasing, month-end close that takes weeks. You become what you spend on, and that's not what you're building toward. Brex is the intelligent finance platform that eliminates that work before it starts. AI agents that handle the manual stuff automatically, so your team can spend their time on what actually compounds. It's time to get Brex AF. Learn more at brex.com slash AF.

1:27these substances that are rearranging themselves to give rise to new substances with the properties we need. But chemical reactions are far from perfect. They're often inefficient and their weight products can be harmful to the environment. Understanding them down to the atomic scale has been a sticking point for chemists. Perhaps not surprising given just how small atoms are. Enter the young scientist Pratiba Gai. Not satisfied with the conventional wisdom that claimed it couldn't be done, she spent much of her career pioneering novel microscopes to bring the seemingly inaccessible world of chemical reactions into sharp atomic focus.

2:05Today Pratibha is Professor Emeritus of Chemistry at York University and her microscope, known as the Environmental Transmission Electron Microscope, is housed in many labs around the world, allowing scientists like herself to observe chemical reactions in real time in exquisite atomic detail and then tinker with them to create products that are not only better for you and me but the environment too. Professor Dane Pratiba Guy, welcome to The Life Scientific. Thank you very much for having me, Jim. Pratiba, I mentioned that chemical reactions are the backbone of modern society, but could you just elaborate on how pivotal they are?

2:43They impact our everyday lives. For example, the medicines we take, the food production for the food we eat, products that we use in our everyday life and climate control processes, they all come from chemical reactions. That's how important they are. And presumably, economically, they're hugely important. Economically, they're extremely important because they put trillions of dollars into the global economy and therefore we need to understand how they work. As I said, chemical reactions are also often inefficient and can create harmful waste. Is there a commonly used product that illustrates that problem?

3:16You know, healthcare companies make paracetamol, which is made using their process, and one of the steps uses sulfuric acid, for example. And there is a waste disposal issue of this acid, and it's not environmentally friendly. And so we came up with a process to get rid of this sulfuric acid step and make this reaction happen. And now it is a very environmentally friendly process. And the microscope you've pioneered allows you to investigate chemical reactions right down to the level of atoms themselves. Exactly. And for example, a grain of salt contains millions of atoms. So imagine if you're eating a CRISPR or something, you will be eating billions of salt atoms.

3:59So it's really very tiny. But as you know, atoms make up everything, right? Yeah. It's a basic building block of matter. Given the minute scale involved, how would you describe the challenge of what you were trying to do, seeing right down to the level of atoms? Yeah, it's like looking at moving golf balls on the surface of the moon from the planet Earth. OK. Can you see them? That's how complicated it is. So that's why we went in steps. We're going to come back to how you achieved this feat with your microscope, Pratiba. But let me first take you back. You were born in Maharashtra state in India, growing up in the 1950s.

4:37What do you remember of being a young child? OK, I have two older brothers, one younger sister and one younger brother. And my father worked in the civil service and my mother was a homemaker. But my father was transferred to different cities in India. India is a big country, so I was exposed to different diversity of opinions, which really helped me in my international career later on. Right, which involves travel. Yes, indeed. And did you, as a young girl, have a particular interest in science? I wanted to be a medical doctor like many of my classmates, but my chemistry teacher was a very knowledgeable lady and she gave me a book on Madame Marie Curie.

5:17And I read that and I was mesmerised because here is a young lady who leaves her homeland, goes to another country for better educational opportunities and overcomes all the obstacles on the way and does something wonderful for humanity and that really inspired me to become a scientist. You saw a parallel in your own life. Because in India in those days, men had a lot of opportunities compared to women. So I thought she might have faced similar obstacles, but she overcame those. You were about eight or nine years old at the time. And I gather you're already imagining studying in Cambridge. Is that right?

5:58Because she was teaching us about gases and she said these gases were discovered in Kevin Nish Laborator, Cambridge University. And I wrote it down and I thought the name was beautiful. And then I said to her, can I study there someday? And she laughed and said, oh, no, no, that's too far away. And it's in the woods and it's very difficult. In the woods. In the woods. It's very difficult to get in. And I was really curious about that. It was in my head all the time. We're going to come back to that shortly. But by the time you were in your teens, you were starting to imagine a future in science.

6:33I gather you wanted to follow in the footsteps of your oldest brother who was studying to become an engineer. My oldest brother is about eight years older than me, so I always looked up to him for inspiration. And they were talking about engineering all the time, they were building things, so I got into building things. And that really inspired me a lot. So, you know, I naturally got into engineering and science and that kind of thing. What about your parents? What ideas did they have for you? They wanted me to go into medical doctor and marry another doctor and settle at home. This is what was expected, right?

7:06I expected and somebody that they would find, probably. And not many women took science as a career. What did that feel like? It was very disappointing, obviously, and that's probably the first time I experienced gender bias in my own home, as it were, because some professions were off-limits to women, so I didn't like that. And you wanted to do what your older brother was doing? Yeah, I wanted to be a scientist. But what happened when I was a teenager, I was selected for the All India National Science Talent Scholarship, which is administered by the government of India. It's an excellent scholarship because it covered all my science education.

7:44So I didn't have to ask my parents for anything. And so I said to them that, yeah, I'm going to study here and here. I mean, having got that scholarship as a teenager, did your parents, were they proud of you? Very proud. Not many women got that award. And so they said, OK, you do science. By 1970, Pratibha Gai, now in your early 20s, you'd completed an undergraduate degree and then a master's in physics and maths at the Indian Institute of Technology in Mumbai. What was that like? It was an amazing experience because I met students from all over the country and because the girls in my hall of residence were doing engineering most of the time, electrical engineers, mechanical engineers, that really opened my eyes that girls can do anything.

8:32And also the girls were going to the United States for the PhD. So I got the idea as well and I applied to the US and I got into one of the top institutes there. But then my brother, who was studying in the UK, he returned to India as a professor and he said, why are you going to the US? Cambridge is the best place to study. Remember that Cambridge was in the back of my head. That was your dream. So I applied and I got admission. So your dream to study at the Cavendish Laboratory of Cambridge came true. Absolutely. So you're awarded a scholarship to do a PhD in physics. Did the Cavendish look like that place in the woods?

9:12It absolutely looked like that. It was a beautiful, small place in the woods. What was it like when you arrived? I went to register myself, and then I found that in our metal physics class, I was the only female student. I said, where are the ladies? I've come thousands of miles away to study here. No ladies. I thought there would be more women because I had several women in our hall of residence when I was doing masters. So anyway, I was the only lady in my class and I looked around all these men, but they were incredibly helpful. They showed me how to cut metals with lathe machine and showed me how to use the electron microscope.

9:51So it was then at Cambridge where you were first introduced to the electron microscope. Correct. Your task was to learn how to use it and come up with a research project for your PhD. Now, we should explain here that an electron microscope is not like a traditional optical microscope, because instead of light, it uses a beam of electrons fired onto the sample. And these instruments are typically very expensive. And they're also very big, aren't they? Often a few metres high. Let's say you have a sample of material that you want to look at, which you've put inside the chamber. How does the microscope work?

10:28Basically, a beam of electron comes through and you collect deflected electrons which contain information. And so it allows us to get structure and composition of these materials, which is very important. So you're using an electron microscope. What was your project? I decided to work on compound semiconductors. And you find semiconductors in almost all electronic devices these days. And LEDs now, because these compound semiconductors that I was going to work on, nobody had looked at defects which control the electrical properties. When you say defects? Defects are imperfections. You know, people are not perfect, right?

11:04We all have defects, imperfections. Crystals have the same problem. They're not perfect. And these semiconductors have a crystal structure. Yeah, crystal structure and some atoms may be missing, some atoms may be added, etc. So they form a defect. But these are incredibly important to understand how the electrical currents are possible or not possible in the semiconductor. And in understanding these defects, the idea was that you could improve the properties? Yes, we could try and eliminate the defects. If they are there, try and improve the properties. I was the first one to actually see these defects structure and analyse them in these complex semiconductors.

11:43Imagine that for a research student, we had amazing reviews that it laid the foundation of defect structures in the entire field. after we published the work, France, Germany, United States, they all started working on this. That's a nice thing to be able to do as a PhD student, to make a breakthrough like that early in your career. Well, after your PhD, Pratiba, you moved to Oxford University. The chemist J.S. Anderson there had been looking for someone like you with electromicroscopy experience, and he wanted to better understand the structure and composition of the compounds he was making. What was it like working with him?

12:22It was an absolute privilege because he was the world-renowned solid-state chemist. He was about to retire and I was about to start my career. So he taught me all the chemistry I know and how to make synthesized compounds and how to use chemical techniques to understand them, etc. So I switched from physics to chemistry because of his influence. And I thought that chemistry was fascinating. As a physicist, I still think physics is important, but that's fine. So you switched from physics to chemistry and soon after that, Pratiba, this is now the mid-70s, you set up your own research group at Oxford in the Department of Materials to use the electron microscope to explore chemical reactions.

13:04Why did you want to be able to do this? Okay, chemical reactions, as we said, they are central to modern society. So we need to understand what they do. So if you don't see it, you don't understand what is actually breaking the reaction or making the reaction. So that's why I was interested to see them. OK, so let's dig into a bit of chemistry now, because for many chemical reactions to take place, you need what's called a catalyst. What is a catalyst and what does it do? A catalyst is a material which we add to chemical reaction to speed up the process. Otherwise, they may take years. So adding catalyst can bring it down to a few hours or a few days or something like that.

13:44And these catalysts, they're solids like metal particles and metal oxides. And you wanted to engineer a microscope that would enable you to observe these chemical reactions taking place in real time. Yes. Why was seeing the reaction in real time important? Catalysts are continuously changing, just like cooking, right? That's why we need to actually watch these reactions in real time. So it allows us to look at good defects and bad defects. And we want to be in the regime of good defects, which are actually making the reaction rather than breaking the reaction. The other thing about chemical reactions is that they require specific temperature and pressure for those reactions to take place.

14:25But the space inside the electron microscope where the sample is placed, where you want to look at these chemical reactions, is empty space. It's a vacuum. So this was a problem you'd obviously need to address for the reactions to take place. It needs temperature, it needs pressure. But first tell me, why is a vacuum necessary in an electron microscope? OK, electron microscope, we use vacuum because otherwise electrons scatter. So we want to maintain the integrity of the electron beam so it can go through the sample. That's why we have vacuum. Which doesn't suit, obviously, the purposes for you just studying your chemical reaction.

15:01So you wanted to adapt the electron microscope to watch these chemical reactions in real time and not in a vacuum, but at the required temperature and pressure. Now, at the time, you had a background in both physics and now also in chemistry. But presumably you'd also need an engineer to build the microscope. Because there was nobody around, I had to build a microscope myself. Having two engineer brothers playing around with different machines and things had helped me a little bit. But I had technological help from a technician. So between us, we came up with this engineering. People were surprised, but I found it not at all daunting.

15:39Were people surprised because you didn't have the background or were they surprised because you were a woman? Because I'm a woman. Whenever I was under the machine, you know, with the screwdriver and thing, they would go up and down to make sure that they were seeing a woman. Well, your first step was to build what you called a nanoscale reactor, a tiny vessel that you place inside the electron microscope. And inside of the vessel is where the chemical reaction takes place. Now, that allowed you to evade the problem of the vacuum and control the temperature and pressure inside this vessel. Can you just give us a picture of this?

16:16What did you put inside? We put a catalyst material and we put the gas and temperature inside the cell. What you're trying to do, I guess, is recreate chemical reaction that typically in the real world would happen on an industrial scale. Yes. But you're doing it in this tiny little vessel. Yeah, amazingly. What you see in the tiny vessel is exactly what happens in the 100-foot reactor. So that's why it is so important to understand. So what did this microscope allow you to see? It took me to the nanoscale resolution. So I could look at these imperfections or defects in oxide catalysts and I could figure out which were good defects, which were bad defects, which were making the reaction or breaking the reaction.

16:59Your microscope meant you could now watch chemical reactions happening in real time to a single nanometre, just a millionth of a millimetre. That's pretty impressive stuff. But you'd mentioned this was a male-dominated field. Did that affect how seriously your work was taken at the time? Yes, at that time there was no woman physics professor in Britain that I was interested in. And I was able to do everything by myself. I could make compounds, I could do electron microscopy, I could do the calculation. And everybody told me that if you are a woman, they won't get published. So it was just myself as an author.

17:39So I didn't know whether it was well-founded or not, but I believed I had to be careful. So I put my initials in my early papers, you know, P.L. guy, so they wouldn't know. Because your initials hid your gender? gender. It was so bad. They all got accepted in Journal of Science, Nature, and also got a very nice grant as well. Well, having published in the top journals, the chemical and life sciences company DuPont, based in Delaware, in the US, had noticed your work and invited you to join the company. They had problems with their chemical processes, and they wanted you with your microscopy skills to improve those processes.

18:20So you started work at DuPont as a research fellow. Alongside this, you were appointed as adjunct professor of material science at the University of Delaware. What was it like working at DuPont? It was fantastic. I just call it my paradise time. I saw women in all positions there. I didn't see any gender bias. I didn't see any gender pay gap. Did you still feel the need to disguise your gender by using your initials and publications? No, in the US they encourage you to put your names on. So if you look at my papers, as soon as I went to the US, all my names are Pratibha Guy. OK, so what was it that DuPont wanted your help with when you arrived?

18:59DuPont is the mother of many polymers. You know, for example, nylon they discovered in the 1930s. It was a hotbed of research. and DuPont had these chemical reactions making polymers and their competition was actually claiming that it's their process. So using high precision electron microscopy which showed that the chemical reaction was actually DuPont's invention and not the competition's. So by proving that the processes were the same, DuPont could stop their competitors from using it? Yes, exactly. Well, I'm sure they were very pleased. Very pleased indeed. So then they told us that you can do what you want.

19:38So this gave you the opportunity you'd been waiting for to pioneer a microscope that would allow someone to watch a chemical reaction beyond the nanoscale, which you'd already achieved, of course, but now zooming in 10 times smaller down to the size of the atoms themselves. How did you feel about this prospect? I was extremely excited and I wanted to be the first human being to watch this reaction. And my spouse was also involved, Edward Boyce. He's also a Cambridge graduate where I met him. And then we had a technologist who was an electron microscope engineer. So he could make the parts in the workshop and put it together.

20:16So we really started three people in a small lab like this, three people against the world. What you were doing here was adapting the existing electron microscope. What did the new task involve? We had to completely re-engineer the inside of the electron microscope. One is to use the electron microscope sample chamber itself as a reactor. So rather than putting a vessel inside this chamber that's in vacuum, the whole chamber becomes the environment for the sample. And then what we did was to drill a hole through the imaging lens to put the gas in. It's like drilling a hole through a person's heart because imaging lens is the heart of the machine.

20:54You're basically sort of destroying a multi-million dollar instrument. It was an extremely nerve-wracking situation because even if we had made a fraction of a nanometre error, we could have killed the poor machine. What did the rest of the scientific community think about what you were doing? Scientific community thought that it was not going to be possible. High temperature, gas pressure conditions, atoms would not be stable. but my calculations proved that it was possible so we went ahead anyway and also the scientific community did not know that we were proceeding with the project because we wanted secrecy.

21:31There are many companies, institutes with better resources than we had and we are just three people and if they come to know about it they would just put it out first and in science you have to be the leader. Well by the end of 1993 Pateba you'd built your microscope, the environmental transmission electron microscope and you began testing it with simple model chemical reactions. But to be confident it will be useful in the real world, you needed to test a commercial sample, starting a complex real world chemical reaction inside the microscope. One evening in 1995, you had the opportunity, but you decided to do the experiment when your colleagues were out.

22:13They had already seen the model systems and I wanted peace and quiet to really see. I was desperate to see if all our efforts had worked. And so I put this red light saying, experiment in progress, please don't open the door. And then I put the industrial sample in and put the gases in. So you got going with the experiment, adjusting the temperature and pressure in the microscope, passing the sample in gas form over this catalyst. and firing the beam of electrons through the sample to image the atoms moving in real time. While you were waiting for it to happen, what was going through your mind?

22:52I was extremely nervous, so I was waiting with anticipation to see what was going to happen. Because it took a few hours, didn't it, to run the experiment. Yeah. And I gather partway through, you were interrupted. Despite my putting a red light on saying, do not enter, it was dark, a gentleman opened the door and came inside, And I said, please close the door. I'm trying to do probably the world's first experiment here. And then he sat next to me anyway, and he took a little notebook, started to scribble some notes. We're going to come back to that man in a moment. But first, back to the experiment.

23:26Having waited, what did you see? First time probably in the world, I saw atomic structure changing, actually atomic level reaction. So you can actually see them moving around as the temperature and gas change. And it was absolutely thrilling, eureka moment for me because we had put in so much effort, so many years of hard work. And so it basically opened up the whole new field of looking at reactions at the atomic level. And this man sitting down next to you quietly taking notes, who was he and what was he doing there? It turned out it was my lucky day. It turned out he was the chief scientific editor of the flagship magazine of the American Chemical Society.

24:07and this magazine goes around the world. So he asked me if he could write an editorial on this fascinating thing that he had just seen. So our papers were accepted and he wrote a three-page editorial. So the whole world came to know about it. How come he was there in the first place? He was actually going to interview the big boss of DuPont and then he lost his way. Just by accident? Just by accident. It was my lucky day, I must admit. Back to your microscope, Pratibha. you could now observe atoms moving in real time in a chemical reaction. So you began to investigate at the atomic level how reactions occur and begin to improve them.

24:45In 2007, you and your husband Edward came back to the UK to co-found the York Joel Nanocentre at the University of York, where as professor of electron microscopy, you refined the engineering of a microscope to make it even more powerful. What was this one capable of doing that the previous version couldn't? The previous version gave us atomic level, which is a string of atoms. And then this one allowed us to look at individual atoms by adding scanning. So by scanning across the sample, you're able to zoom in to the motion of individual atoms rather than a string. Correct. We went to the single atoms.

25:24Being able to study chemical reactions at the atomic scale has sparked some fantastic innovations, like creating novel products or making chemical reactions more efficient and environmentally friendly. While the advances to the various chemical reactions that you've made with the help of your microscope are under patent with various companies, you made the decision not to patent the microscope itself. Why was that? First of all, I'm not interested in making money from science and I wanted other scientists to use this development that we had made to do more fundamental research and come up with more chemical inventions to help humanity, basically.