Over the years, A*STAR has built deep capabilities in fields such as high performance computing, modelling and simulation, materials engineering, bioimaging, and more.
When the COVID-19 pandemic hit our shores, our scientists and researchers started looking at ways that can help Singapore combat the pandemic. A*STAR has since conducted a number of scientific studies related to the importance of wearing masks, safe distancing and minimising the risks of transmission from droplets and aerosols. The research findings from these studies will allow the public to be better informed about safe management measures and why they are important.
Here’s a look at the A*STAR team behind this body of work.
Multidisciplinary R&D for Better Outcomes
A team of 15 scientists from various fields of expertise worked hand-in-hand to study the spread of droplets and aerosols when a person coughs or sneezes in Singapore's tropical environment. The combination of A*STAR’s Institute of High Performance Computing (IHPC)’s computational modelling expertise and the Institute of Materials Research and Engineering (IMRE)’s experimental design and particle sensing capabilities allowed the teams to cross-validate the findings, and quantify potential aerosol exposure levels in different settings and social distancing, such as in public spaces.
Dr Dan Daniel is Group Leader at The Droplet Lab in IMRE. His field of research is in the physics of droplets - how the droplets are formed, and their interaction surfaces.
“I was initially doing research on the interactions of droplets with surfaces but decided to pivot to COVID-19 research, since my expertise of flow and droplet physics is highly relevant to understanding COVID-19 transmissions." – Dr Dan Daniel, Group leader, IMRE
Dr Dan Daniel (left) with Dr Anton Sadovoy reviewing the test results of the droplet airflow experiments.
Dr Daniel worked closely with Dr Kang Chang Wei, Senior Scientist and Deputy Director of the Fluid Dynamics team at IHPC, and Dr Ivan Tan, Head of the Soft Materials department at IMRE, to study the flight trajectory of droplets and aerosol particles. This study allowed the team to delve deeper into how droplets spread under different environmental conditions.
“Throughout the year 2020, we were honored to be given the opportunity to contribute our scientific knowledge and work with many partners including other A*STAR research institutes, Institutes of Higher Learning, public agencies, event organisers, and venue operators. All the collaborative efforts are seamless and borderless. Everyone gives his or her very best as we have one common goal –to support Singapore to gradually re-open its economy and social activities safely. Although in many instances we were under extreme time pressure to deliver, collectively as a team, we managed to provide our best to the studies related to ventilation in spaces, and minimising droplet and aerosol transmission for various venue settings.” – Dr Kang Chang Wei, Senior Scientist, IHPC
From Left: Dr Kang Chang Wei and Dr Ivan Tan
Working alongside the team is Dr Li Hongying, a scientist from IHPC who plays an integral role of developing complex algorithms to incorporate the key physics principles. This makes the team’s modelling system more robust and accurate. Dr Li was also instrumental in getting the team’s work in the Physics of Fluids scientific journal to share their computational efforts and scientific knowledge with the global community.
Clockwise from Left: Dr Kang Chang Wei, Dr Li Hongying and Dr Leong Fong Yew in a discussion on airflow modelling and simulation.
Birth of “Dr Kauffman”
To better understand the flight trajectories of droplets and aerosols, scientists from IMRE designed a mechanical coughing model, known fondly as “Dr Kauffman” (spin on “Dr Cough-Man”). This model is able to generate droplets and aerosol with similar size ranges and flow profile as a real cough or sneeze. Subsequent variations of the model were used in related experimentations on aerosol and droplet studies to look at potential viral spread in different situations.
"I recall it started during Circuit Breaker, almost every week, we had to do a site survey and conduct physical experiments to come up with the computational model within a short timeframe. We engaged our physicists on droplet research, and came up with an aerosol generator, which we have modified to better understand how droplets and aerosols travel." – Dr Ivan Tan, Head of the Soft Materials department, IMRE
Dr Kauffman is able generate droplets and aerosol with similar size ranges and flow profile as a real cough or sneeze.
A Quest for Quality Air
A team of A*STAR scientists from IMRE and the Singapore Institute of Manufacturing Technology (SIMTech) studied the effectiveness of plant and natural fibre ionisers, as well as air filters, and found them to be very useful in reducing aerosol concentrations in the air, especially in poorly ventilated areas.
Dr Chng Shuyun, Deputy Group Manager of the Surface Technology Group at SIMTech, and her team of researchers have developed an anti-microbial and hydrophobic coating that is suitable to be coated on a variety of materials. The coating has excellent efficacy against bacteria and viruses, is durable and versatile for various applications. This technology has been licensed to a local SME, and the company is currently working together with the team for the coating manufacturing and production.
The team, together with Mr Goh Chee Chien, Senior Industry Development Manager, SIMTech, worked with another local SME to tailor this anti-microbial and water-repellent coating for air filters. The company has its propriety filter materials and through the collaboration with SIMTech, the coated air filter is now able to filter, inhibit and capture pathogens. The tailoring of the coating involved tweaking of the formulation for compatibility on the filter material, and detailed investigation of the coating deposition methods and parameters. After optimisation, the coated filter is now able to filter up to 97% of bacteria and 95% of viruses (evaluated by Bacterial Filtration Efficiency (BFE) and Viral Filtration Efficiency (VFE) tests). The team is now working with the company to look at mass production of the coated filters, which can be fitted on the rear of fans.
From Left: SIMTech researchers Ms Ang Wei Ting and Ms Ng Shu Pei testing the efficacy of the anti-microbial and water repellent coating for air filters.
“It gives our team great satisfaction to see the coating we have developed being applied onto filters, and have its performance verified by our colleagues at IMRE. We are grateful to be able to contribute in our little ways through the technology we have developed and through this collaboration, to help in the fight against the pandemic.” - Dr Chng Shuyun, Deputy Group Manager, SIMTech
SIMTech researchers who worked on the anti-viral coating and the coated filters. From left: Ms Ng Shu Pei, Mr Lee Zhao Yun, Dr Chng Shuyun, Ms Ang Wei Ting, Ms Qian Min).
In the studies, IMRE further tested the efficacy of the filters and showed that in a typical office meeting room the size of about 117m3, the use of two fans fitted with air filters with anti-microbial coating can bring down the time needed to reduce aerosols to 10.5 minutes, compared to 15 minutes without such fans fitted with air filters.
Experiment conducted by IMRE to study the efficacy of fan filters in reducing the spread of aerosols.
Dr Ady Suwardi, Deputy Head of Soft Materials, IMRE, and Dr Davy Cheong, Senior Scientist, Division Director, IMRE, discovered that plant and natural fibre ionisers enabled a lower risk of transmission depending on the quantities of such ionisers and air filters within rooms of specified sizes.
The team found that with the presence of plant or natural fiber ionisers, the time taken for aerosols to clear can be reduced to as low as 3 minutes in a 0.5m3 enclosure. In terms of Air Change per Hour (ACH), natural fiber ionisers yield an ACH of over 20 in a poorly ventilated enclosure, which far exceeds ventilation requirements for hospitals and surgery rooms as well as CDC’s recommendation of 6 for healthcare facilities and isolation wards1 .
From Left: Dr Davy Cheong and Dr Ady Suwardi
"We have learnt a lot from this research, we went really deep into the science, and our research was eventually published in a paper. I would say we have benefited from this new knowledge as well.
Personally, the biggest takeaway is that to achieve meaningful outcomes, we needed collaboration between multiple parties, and through this project, we had the chance to work with many agencies that we would otherwise not have engaged. It is quite interesting and a good learning process for us." - Dr Ady Suwardi, Deputy Head of Soft Materials, IMRE
"I think this research is particularly meaningful, especially when it can contribute to Singapore's safe reopening. As a scientist in A*STAR, I’m grateful that it gives us the opportunity to be at the forefront of contributing in terms of science and technology for the betterment of Singapore." - Dr Davy Cheong, Senior Scientist, Division Director, IMRE
Disinfecting Surfaces for Enhanced Hygiene
High-energy UVC rays can inactivate viruses by damaging their RNA and DNA, however, there is limited literature on UVC’s effectiveness against COVID-19. In this study, the research team at A*STAR’s Singapore Bioimaging Consortium (SBIC) and SIMTech established the appropriate UVC doses needed to inactivate different types of viruses2 and bacteria without causing damage to the surface materials. For instance, with a wavelength range of 254-280nm, UVC rays are effective at inactivating coronaviruses up to 99% in 5 minutes. However, such UVC solutions are not eye and skin safe, and not meant for household use.
Dr Ong Qunxiang, Research Fellow from SBIC is one of the key researchers involved in this study.
“I have been studying the effect of light on photochemical and photobiological processes. As COVID-19 started to impact the entire world, I thought I could contribute by studying the mechanisms of how different wavelengths of UVC inactivate pathogens and degrade components of coronaviruses. It has also been really meaningful to perform experiments that could advise on the implementation of the technology, and I am really proud of the multidisciplinary nature of the team” – Dr Ong Qunxiang, Research Fellow, SBIC
Dr Ong Qunxiang, Research Fellow, SBIC adding coronavirus viral inoculum onto test plates for UVC testing.
Dr Ronnie Teo, a scientist from SIMTech, developed a high-efficacy UVC solution that can rapidly inactivate up to 99.9% of human coronaviruses without causing damage to materials. This solution has been licensed to various industry partners and is currently being test-bedded in public spaces for the disinfection of furniture, food crockeries, as well as meeting rooms and toilets.
“I am elated to see the translation of our research to the industry with both local and overseas deployments. I hope our solutions will not only strengthen our resilience against the current pandemic but also improve Singapore’s hygiene standards and help ward off future health threats.” - Dr Ronnie Teo, Scientist, SIMTech
Dr Ronnie Teo testing his high-efficacy UVC solution prior to on-site implementation.
A*STAR’s IHPC also contributed their optical simulation expertise in enhancing safe implementation of existing UVC solutions. Using its ray optics capability, Dr Jason Png and his team enhanced the application safety gap in the emerging UVC LED technology with clearly defined safety zone during its deployment. They have also worked with other A*STAR research institutes to develop safety guidelines during the on-site testing, and was able to determine the kill-time for different strands of bacteria or viruses in the practical scene based on the experimentally derived efficacy data.
Source: Guidelines for Environmental Infection Control in Health-Care Facilities, taken from the Centers for Disease Control and Prevention (2003)
2 Viruses tested include human coronaviruses 229e and OC43 for the surrogates.