Pratibha Gai takes multimillion pound electron microscopes and drills tiny holes in them to make atomic movie cameras. She tells Celeste Biever about her quest to understand the secret life of atoms, which helped her to scoop a L'Oréal-UNESCO For Women In Science award on 28 March.
Electron microscopes can take images of single atoms. What more did you want to see?
Conventional electron microscopes operate only in a vacuum and often only at room temperature. But many chemical reactions happen at elevated temperatures, and in a gas, so we really cannot use the microscopes to get inside the reaction as it is taking place. To understand these processes, we need to be able to watch them directly.
So what did you decide to do?
It suddenly occurred to me, why not drill a hole through the imaging lens, and put gas through there, where the sample is? That way I wouldn't have to take the machine apart, and everything would be integrated. But it's very challenging – the gas pressure is a billion times greater in this 5-millimetre hole than in the rest of the experiment.
How much did the machine you were planning to drill into cost?
More than $1 million.
Were you nervous?
That's why I made a mock up – it had to be done on a model first. When that was successful, I tried the real thing. Everybody had gone up to a meeting. I put the gas in, I heated it and turned the beam on.
I held my breath and I looked up at the monitor – it's real time – and I saw, for the first time in the world, atoms working in chemical reactions, changing their atomic structure. That was a wow moment. It was absolutely thrilling.
You first did this in 1993. How are these insights changing the world now?
We are using it to help convert plants into biofuels, especially biodiesel. Using the microscope, we saw that tiny defects on the surface of the catalyst were very beneficial to the reaction. This allowed us to improve the performance to give us more product. We have also been working on antibiotic nanoparticles to control infections in medical implants. When we simulate the wound environment, we see that they are incredibly potent.
So if you understand how atoms work, you can make reactions more efficient?
It is more economical if we can train atoms to do the reaction we want rather than let them do their own thing. You can see the power. Instead of using tons of material, we could just use a few thousand or million atoms to do the same work. It would save a lot of money in terms of materials.
Have you patented your hacked microscope?
I am a scientist – I believe in scientific research. I did it to study chemical reactions. After I published it, I wanted it to be available to other researchers. If you patent it you can't publish all the details. By publishing, I could help other people and it was good also for us to get grants, research funding.
Some people think chemistry is boring…
Oh no, it is exciting.
But even you didn't start out as a chemist…
When I left school in India, I went to Cambridge to do physics. At that time, outside microscopy, I wasn't interested in chemistry. But then I went to work with a chemistry professor in Oxford, who was really pretty instrumental in enthusing me about chemical synthesis. And then I realised I could use my electron microscopy knowledge from Cambridge to understand what I made. It was a tremendous combination. I went to a meeting and I said nobody has done this before. And unless you do something new – totally insane – nobody is going to take any notice. Especially for women.
There couldn't have been many women in your field back then…
At Cambridge, I was the only woman in my group. It was a bit discouraging because I think at least in those days – 3 decades ago – physical science was still a male preserve.
How did you cope?
They accepted me as a scientist but I think in the workplace you had to work harder than a man to get recognition. There were no role models in those days. I realised that that one thing that is nice thing about science is that if you have an idea, get some results, you can actually publish it and they need not know you're a woman.
Did you learn anything from these challenges?
I learned that I had to be pretty good to compete, and therefore I had to work harder. And what I did was I found my own niche. As a leader in a field, the focus is on what you are achieving rather than your gender. So it is important to go for something new – if there are already other people in a field, you are not going to be very successful unless you are brilliant.