Over the past 15-plus weeks, how many times in a day have you furiously wiped down surfaces with disinfectants? The COVID-19 fear factor has turned scientists to research on products based around nano technology, the application of a group of few atoms. They are looking for a solution aimed at a surface coating that bonds to the material with long-term protection against germs (bacteria, viruses, fungi, protozoa).

What are these surface protectors?

They are substances that use metals such as silver and copper or biomolecules such as neem extract known for their microbial activity, or cationic (i.e positively charged) polymers in combination with chemical compounds (like ammonia plus nitrogen) that can be used as a long lasting protective coating. The compound can be sprayed on metal, glass, wood, stone, fabric, leather, and other materials and the effect can last from a week to 90 days depending on what type of surface it is used on.

Are they out in the market?

Until the pandemic, there were products for anti-bacterial application, but now the focus has shifted to viruses. For instance, Prof Ashwini Kumar Agrawal, the Head of Textile and Fibre Engineering Department at IIT Delhi, developed N9 blue nano silver in 2013, with a much higher potency than other metals and polymers to catch and kill bacteria. He has now evaluated the anti-viral properties and re-formulated the compound to work against COVID-19. He says different kinds of silver (yellow and brown) have been patented by countries including the US, China, Australia to establish the uniqueness of the metal for surface hygiene. "But the N9 blue silver can be 100 times more effective with the longest lasting protection."

Institutions (particularly the IITs) across the country are in different stages of developing these nanoparticles as surface coatings. All are awaiting validation against viruses, through field trials before they can legally mass manufacture.

The required certification needs to ideally go through government-approved labs (like ICMR, CSIR, NABL or NIV) that are currently all engaged only in research on medicinal drugs and vaccines.

Nano-products that are available

There are some products that have been tested by private labs either in India or abroad. For instance, Delhi-based start-up, Germcop has launched a disinfection service with a US manufactured and EPA-certified water-based anti-microbial product which, it is claimed, when sprayed over metallic, non-metallic, tiled and glass surfaces gives protection up to 120 days with a 99.9% killing rate in the first 10 days. Dr Pankaj Goyal, the founder, says the product is good for homes that have had a COVID positive patient home-quarantined. She is speaking to the Delhi Transport Corporation to disinfect 1,000 buses. However, the testing has been conducted in a private lab.

IIT Delhis samples were sent in April to the microbiological testing laboratory, MSL in UK. The reports are expected only by the end of the year. "The battery of lab tests will confirm the efficacy of the compound in dry state, how fast and for how long it can continue to kill the virus and if it is non-toxic and safe to use," says Prof Agrawal.

While Prof Agrawals N9 blue silver comes under the Government of Indias Nano Mission project funded by the Department of Science & Technology, another by IIT Madras, funded by the Defence Research Development Organisation, has developed a nano-coated filter for PPE kits, masks, and gloves that can be used by frontline healthcare workers. The coating filters sub-micron sized dust particles in the air. However, its practical application is also subject to field testing and is therefore, pending.

Why cant we just use regular disinfectants?

We can, but theyre not a healthy option for us or the environment, over a long term. Dr Rohini Sridhar, the COO of Apollo Hospitals in Madurai, says common disinfectants used so far in high density public places such as hospitals and clinics contain alcohol, phosphates or hypochlorite solutions, more commonly known as household bleach. "These solutions lose their function as they evaporate quickly, and break down when exposed to UV lights such as the sun, requiring the need for surfaces to be disinfected several times a day.

Are the long lasting surface protectors in use anywhere else in the world?

Following the findings from the Diamond Princess cruise ship that the coronavirus can last on surfaces up to 17 days, the development of a new disinfectant technology arose. While anti-viral coatings are undergoing clinical tests in several countries, three months ago scientists from Haifa's Institute of Technology, in Israel, claimed to have developed anti-viral polymers that could kill the coronavirus without getting diminished.

Researchers in Hong Kong University of Science & Technology also developed a new anti-microbial coating known as MAP-1 that can kill most bacteria and viruses -- including the coronavirus -- for up to 90 days.

Prof Agrawal says many countries are engaged in developing heat-sensitive polymers that respond to contamination from touch or droplets, from the time of previous epidemics of SARS. Many of those formulations have been modified during the current pandemic and sold under different brand names in Japan, Singapore, and the US. However, the surface protectors currently available in international markets are pocket-pinching.

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Tiny particles, big solutions - The Hindu