SINGAPORE – Scientists from the Nanyang Technological University (NTU) have developed a reusable mask that is able to kill bacteria droplets within 45 seconds and filter 99.9 per cent of bacteria, viruses and haze particles – better than the medical-grade N95 masks used in hospitals.
N95 masks are able to prevent around 95 per cent of aerosolised droplets and particulate matter of around 0.3 microns in size from entering them.
The filter of the NTU-developed mask is coated with a layer of copper oxide nanoparticles, which damage the DNA of important cell structures in the bacteria, causing them to die, said Professor Lam Yeng Ming, chair of NTU’s School of Materials Science and Engineering, who developed the antimicrobial coating.
To ensure these microbes remain trapped on the filter, Associate Professor Liu Zheng managed to integrate electrostatic materials to the fabric filter made from polypropylene, so that particles, including bacteria and viruses, with a negative or positive charge can be attracted to it.
To test the efficacy of this, experiments were conducted in collaboration with scientists from the National University of Singapore, where multi-drug resistant bacteria that were sprayed in droplet form onto the fabric surface were killed in 45 seconds.
Asked if the copper oxide nanoparticles are also able to kill viruses such as the Sars-CoV-2 virus which causes Covid-19, the team said various peer-reviewed studies have shown that these coatings can reduce surface transmission of the virus, though they had not experimented with it.
For instance, in a study conducted by The University of Hong Kong and Virginia Tech in the United States, door handles coated with a layer of copper oxide material had shown that the infectivity of the Covid-19 virus was reduced by 99.8 per cent in 30 minutes and 99.9 per cent in an hour.
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The NTU team tested their nanoparticle coating by washing it in soap water at 45 deg C for 120 washing cycles, and found that there was almost no copper loss, posing little risk of toxicity to humans.
The nanoparticles are also bonded to the fibres within the mask, so there is no contact with human skin.
With these properties integrated into the mask prototype, Prof Lam said that the mask is well-equipped to protect one from Covid-19.
With the electrostatic fabric integrated into the mask’s filter, its filtration efficiency is higher compared with mask filters made purely of polypropylene, which typically have a bacterial filtration efficiency of 95 per cent, like surgical masks, said Prof Liu.
In comparison, the NTU-developed mask has a bacterial filtration efficiency of 99.9 per cent, meaning that it is able to prevent 99.9 per cent of bacteria-containing respiratory droplets that are around three microns in size from escaping.
A cough typically expels droplets that are between five and 20 microns in size.
At the same time, the mask is also able to prevent 99.9 per cent of aerosolised droplets and particulate matter that are around 0.3 microns in size from entering it.
Therefore, the mask’s filtration efficiency surpasses that of an N95 mask but allows the wearer to breathe more easily, since it contains only a single filter, said Prof Liu.
Comparatively, N95 masks may contain multiple layers of filters to trap the haze and smoke particles, which make breathing more difficult, he added.<img alt="" data-caption="Associate Professor Liu Zheng (left) holding the nanotech mask with Professor Lam Yeng Ming holding the copper nanoparticles in a bottle.
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Masking Up: Health Ministry Sets New Standards Amid Rising Covid Cases
- Why the change? The Ministry kicks back the rule for masks: choose ones that are at least 95% effective at filtering out bacteria. The world’s got new variants dancing around, so we want to keep the good vibes.
- Cool tech coming in Prof Lam’s team at NTU has an antimicrobial coating that keeps doing its job for up to six days straight. And the breather? You can wash the mask over ten times and it still sticks to its 95% promise.
- Still something to research Researchers still need to stress-test how many washes a mask can survive before its power dips. We’re on it.
- Patent action NTU’s spin‑off, NTUitive, guards the intellectual property. Lab partners are already tunneling with Sportiv Tech Lab to bring this mask into the real world.
- Made for comfort Electrostatic fabric—now exported to overseas manufacturers—lets these N95 masks feel like a sigh of fresh, breathable air, not a sandstorm.
- Ready for launch The goal? Partner with local factories to license and scale up production. The mask is on sale now, and we’re hoping it hits the market worldwide.
All laid out in plain English—because a mask is a mask, not a NASA briefing. Stay covered, stay safe.
