This cage could save lives one day

NTU's bioengineer Sierin Lim works on folding proteins into "cages" that can smuggle drugs into the right part of the body. Protein cages can also be used to hold MRI contrast agents which help parts of the body show up better on scans, so tumours can be detected at earlier stages, for example.
PHOTO: This cage could save lives one day

Q:You were born in Jakarta to parents in the faucet distribution business; how did your upbringing influence your career choice?

My mum was the big driving force. When I was young, my mum used to take us to bookstores and plop me and my brother at the science section, and we just started reading. From there I developed an interest in science. My mum was also very interested in what I was doing; she liked science but she didn't have the chance to do it.

Q: What is biomedical engineering?

It's basically applying engineering principles to biology, to solve problems that pertain to human health and medicine.

Q: How did you get interested in your field of research?

In 1997, I started my undergraduate studies at UCLA (University of California, Los Angeles). I was in a chemical engineering class that I really enjoyed, and asked if I could work with the professor, who studied enzymes and scaling up the bioreactor process.

Then in 1999, I was walking around campus and saw a poster describing the Nobel Prize-winning work of UCLA chemist Paul Boyer, John Walker and Jens Skou, who studied ATP (the "engine" that drives cells). I wrote to the Royal Swedish Academy of Sciences to ask for a copy, and never expected they would respond. But a few months later, a tube containing the poster arrived. So maybe that was a sign for me to go to graduate school!

For my PhD, also at UCLA, I switched to biomedical engineering, studying how enzymes break down and reassemble carbon sources into amino acids.

The idea was to use those enzymes to do other things eventually, such as making new molecules.

Four-and-a-half years later, the day before I filed my PhD thesis, I met Paul Boyer. I asked him what his advice was for young scientists, and he told me: "Keep looking for new problems to solve."

Q: What is your work about?

As a post-doctoral researcher at UC Irvine (University of California, Irvine), I studied nano-scale protein "cages". These are strands of proteins folded into cage-like structures. Protein cages are found in nature. For instance, ferritin (a protein produced in the body) stores and releases iron.

When I came here, I wanted to further engineer these things - to understand the assembly mechanism of this cage so we can specifically control their disassembly. Protein cages are good for drug delivery. You can engineer them very specifically to home in on cancer cells instead of spreading drugs all over the body, and break apart when they get to their destination.

Protein cages can also be used to hold MRI contrast agents which help parts of the body show up better on scans, so you can detect tumours at earlier stages, for example.

Q: What is a typical work day like?

As a professor, I'm a scientist, teacher, writer, business manager, motivator, mentor, and PR person all rolled into one! I come to the office and read and write papers and proposals, and prepare for lectures. For every hour of lecture, I have an hour or two of preparation. I live on campus so it's too easy to never go home.

Q: How do you encourage young people to go into science?

I'm involved in the Biomedical Engineering Society (Singapore) and helped to set up the student chapter, which helps students understand what the field is and how it fits into society.

I've opened my lab to students. Mostly they are from secondary schools or junior colleges, but sometimes are even in Primary 5 or 6. For them, I leverage on the "wow" factor. That spark of interest might help them decide on science in the future.

And on Nov 7, Marie Curie's birthday, I'm organising a symposium to get women in engineering, science and technology to speak to younger students.

Q: Why women in particular?

Because we would like to encourage more future female scientists, engineers and technologists; I want to encourage more young girls to consider this as their career path. If we don't, we are losing talent and different ways of looking at problems.

Q: What keeps you going and why do you keep looking for new problems to solve?

I think there are a lot of things we don't understand in science. How do protein cages assemble? Why do they bother doing that kind of assembly? Why is that important in terms of function? From an engineering point of view, after we understand them, what do we do with that understanding?

Once I understand how these molecules come together I can engineer them in a very particular way, so they respond to pH or different cues in the body.

It's not always easy. Many times the experiments don't work; or you write grants, and the grants don't get funded. After so many of those, you hit some hard times. The ability to tell yourself to keep going, and that at some point you will get somewhere, is another skill you need to learn.

This article was first published on August 3, 2014. Get a copy of The Straits Times or go to for more stories.