Preventing Super Bugs

A*STAR’s Dr Siti Nurhanna Riduan, who trained overseas on an A*STAR International Fellowship, explains how the materials she has invented kill bacteria without the risk of encouraging drug resistance.

A*STAR’s Dr Siti Nurhana Riduan is developing materials that kill harmful microbes such as bacteria and viruses, in ways that do not lead to superbugs.


With drug-resistant bacteria linked to almost five million deaths in 2019, according to a recent global study, the Agency for Science, Technology and Research’s (A*STAR) Dr Siti is developing materials that kill microbes, including bacteria and viruses, in non-chemical ways so that they do not lead to superbugs.


Dr Siti, 39, a Senior Research Scientist at A*STAR’s Institute of Bioengineering and Bioimaging specialising in green chemistry and antimicrobial materials, said that the materials are rough on a nano or micron scale.


“Think of the bacterial cell as a balloon,” she said. “Our materials have surfaces with many tiny needles on them. When the cell touches them, it bursts.”


“When people touch them, though, they don’t feel rough. We did biocompatibility and animal studies for the materials, and these did not show any detrimental effects.”


During her research, she also found that the materials were killing bacteria that did not come into contact with them.


She said: “My team investigated and discovered that the materials were releasing reactive oxygen species. These are ubiquitous in nature and found even in the human body, but too much of them kills microbial cells.”


“After we understood the materials’ characteristics and what kind of reactive oxygen species were being released, we were able to finetune the characteristics to release what species we wanted, when we wanted.”


Her team has licensed their work to an A*STAR spinoff firm, which is currently considering industry partners to push the technology beyond the bench. This includes incorporating the materials into paints, plastics, fibres and other everyday materials.


Dr Siti said that she has been interested in chemistry since she was a child. “I borrowed books for do-it-yourself chemistry experiments and did small ones in the kitchen. I wasted a lot of salt lowering the melting point of ice, and nearly spoiled my mother’s iron by ironing a piece of paper that I had used lemon juice to write an invisible message on.”


A two-year postdoctoral stint at the California Institute of Technology (Caltech) from 2014 to 2016, funded by an A*STAR International Fellowship, was formative.


The Fellowship provides support for up to two years of overseas postdoctoral research training. Recipients return to Singapore afterward and work in A*STAR research institutes for three years.

Taking research beyond the lab, Dr Siti has licensed her team’s work to an A*STAR spinoff firm.


She recalled: “I was working with a group studying the principles of small molecule activation. The experience exposed me to the rigours of academia and research.”


“I also made many friends and keep in contact with them and my supervisor there. They are part of my support network, and I can ask for advice when I need it. The Fellowship was a great opportunity.”


She is paying the guidance that she has received forward, by mentoring young scientists.


She said with a laugh: “This has helped me too, when my interns ask me questions and keep me on my toes. The pursuit of knowledge is what keeps all of us researchers going.”


About the A*STAR International Fellowship


The A*STAR International Fellowship (AIF) is a scholarship that will fund post-doctoral training at leading research institutions or universities overseas, providing candidates with opportunities to expand their research experience and deepen their knowledge in their chosen field.

Upon completing their post-doctorate training, candidates will embark on an exciting career at one of the A*STAR research institutes of their choice.


Find out more here.


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