Peter Tsai couldn’t sleep. The 68-year-old Taiwan-born scientist, world-famous as the man behind the present-day N95 respirator — the last defence against the Covid-19 virus for healthcare workers around the world — had retired last year.
However, this January, he was flooded with emails and phone calls that had a common refrain: could he suggest a way to make the N95 mask reusable? Since the masks could only be used once in vulnerable environments like hospitals before it lost its virus-stopping potency, the world remembered him again.
Tsai decided to come out of retirement and now believes that he has cracked the case.
“You know the funny irony in all this?” Tsai tells The Indian Express from his home in the US. “The charging technology that I had used in 1992 to make N95 capture the virus was called ‘Corona charging’.”
Now, he was called to stop the coronavirus. The technique he used in 1992 was the electrostatic charging on the microfibres on the mask that improved the filter efficiency ten times, allowing it to stop the sub-micron-sized microbes.
“I couldn’t sleep when the calls and mails started to pour in. In fact, the last two months I haven’t slept much, but now I think I can relax a bit,” Tsai says.
“Heat treatment is the best of the solutions that I have come up with now. Heat the mask at 70 degrees for 60 minutes. That should deactivate the virus, and make the mask resuable. There are other solutions like steaming etc but this heating holds the most promise. FDA and others are looking at it now. There was talk about using UV rays but I suspect it can degrade the polypropylene material of the mask.”
Tsai might have cracked the puzzle in short time, but it had taken him a long time to solve it in 1992. “Five long years. We knew it had to do something with charging the microfibres on surface of the mask and we tried everything.”
Tsai has always found a way out of a crisis. The son of a poor rice farmer, he had to struggle to achieve his goals. “I worked for five years after graduating college in Taiwan in 1975. We didn’t have much money at all. I had to save up for travel and studies in America. I was working in textile industry in quality management when I realised that the country lacked research and development work. All we did was production; technology and equipment came from Japan or US or Europe. I went to Kansas State University to study.”
He astonished many there by signing up for 500 credits, though a PhD student only needed 90 credits to graduate. He took up courses across the spectrum: mechanical engineering, material engineering, electrical engineering, chemical engineering, physics and mathematics. “I wanted a good base in mathematics and became a teaching assistant.”
That multi-discipline curiosity would later help him in fortifying the respirator.
“I didn’t invent the N95 mask. The charging method that increased its filtration is my contribution. I combined two technologies — melt blowing and electrostatic charging — to produce a layer of melt-blown fabric that is at the core of the respirator mask.”
Melt blowing turns fibers into nonwoven fabric with very fine pores. The electrostatic charging gives the fiber electric charge that traps and stops the sub-micron viruses and bacteria. “My initial respirators were for construction and painting workers and painting workers. It was later used for healthcare mask.”
It’s now the major shield in the Covid-19 world. In 2018, he had come up with hydro triboelectrification process for air purifiers. “You apply the same to N95 to reduce half its material and importantly, it increases the filtration ten times more.”
Tsai is a hero in the medical world now. “I am so glad that my invention has helped to save lives. You know some of my professor friends jokingly say that I should get a Nobel prize. You know what I tell them? I should get the ‘NoBelly’ prize as I have lost all my stomach-fat due to sleepless times in the last two months,” he says.