Anti-viral surface coating to prevent spread of novel coronavirus through touch

By OEM Update Editorial May 13, 2020 10:46 am IST

As declared by World Health Organization (WHO), presently the whole world is facing a pandemic and a global crisis caused by a novel virus that was discovered to be the cause of a large and rapidly spreading outbreak of respiratory disease, including potentially fatal pneumonia, in Wuhan, China (starting 9th January 2020). The virus was provisionally designated 2019-nCoV and later given the official name SARSCoV-2, and the disease caused by the virus was officially named Coronavirus Disease 2019 (Covid-19) by WHO.

The SARS-CoV-2 is an enveloped, positive sense, singlestranded RNA virus. Coronavirus is so named because of its characteristic solar corona (crown-like) appearance when observed under an electron microscope. This appearance is produced by the peplomers of the surface (or spike; designated S) glycoprotein radiating from the virus lipid envelope. The SARS-CoV virion is spherical with an average diameter of 78 nm.

SARS-CoV-2 is a delicate but highly contagious virus capable of spreading primarily from person to person around the world. It also spreads when an infected person coughs or sneezes and a droplet lands on a surface or object; when a person touches the surface that has the virus on it and then touches his/her nose, mouth or eyes, he/she could pick it up. On the personal level, hygiene measures are recommended to prevent the spread of the disease, especially in institutions where individuals are in contact with patients or contaminated fomites. Washing hands with soap and water or with alcohol-based hand rubs is effective for interrupting virus transmission. Although viruses don’t grow on any nonliving surfaces, recent studies show that coronavirus can remain viable or infectious on metal, glass, wood, fabrics, and plastic surfaces for several hours to days, irrespective of the surface looking dirty or clean.

However, coronavirus is relatively easy to destroy using simple disinfectants like ethanol (62-71 percent), hydrogen peroxide (0.5 percent) or sodium hypochlorite (0.1 percent) that break the delicate envelope that surrounds the tiny microbe. However, it’s practically impossible to sanitise surfaces all the time and it doesn’t guarantee that the surface won’t get contaminated again. It’s a much wiser solution in such a scenario if the surface can repel the pathogens, making it nonstick, and/or “sanitise by itself” by neutralising the contaminated pathogens quickly, thus eliminating the possibilities of transfer of microorganism to the human body and its subsequent spread. Studies show that the spike glycoprotein of COVID-19 allows the virus to dockand bind to the ACE2 surface proteins of human epithelial cells in the respiratory track, thereby infecting these cells. Association of the COVID-19 spike glycoprotein with host ACE2 surface protein is a crucial step for infection.

Our research aim is to create a surface coating with relatively low surface energy value which may repel the spike glycoprotein to anchor the surfaces of landing, also use of active chemicals which could inactivate the spike glycoprotein as well as viral nucleotides. As we already have developed an anti-microbial coating solution virtually for all surfaces with effective combination of nano-actives, having proven literature supporting it as antiviral too, we are pretty convinced about its performance as an antiviral that should resist the transmission of virus from nonliving articles to living body cells by touch.

Literature survey shows that the nanoparticles (NPs) of various metals and metal oxides like zinc oxide nanoparticles (ZnONPs), cuprous oxide nanoparticles (CuONPs), silver nanoparticles (AgNPs), nanosized copper (I) iodide particles (CuINPs), gold nanoparticles on silica nanoparticles (Au-SiO2NPs) and also some quaternary ammonium cations commonly called QUATs are very promising to inactivate virus and are well-proven.

The product we have developed, NANOVA HYGIENE+TM, as an anti-microbial coating for surfaces like fabrics, plastics, metals and concretes contains the cocktails of non-migratory QUATs and positively charged AgNPs as bioactive nanoparticles and dispersing this into binder polymers. This anti-microbial coating also shows extremely low surface energy value (>20 mN/m) and behaves as an omniphobic surface by repelling water and oil together. Contact angels were >130o and >50o when measured against water and hexadecane as probes, respectively. This coating has proven test reports on protection against bacteria pathogens up to 99.9 percent as per the global standard JIS Z2801. The coated surfaces also have evidence to work effectively against fungi and algae pathogens.

From the available published data in literatures, we can safely opine that NANOVA HYGIENE+TM would be a potential coating candidate to repel and inactivate virus on the surface, and hence could be a potential material to address the present problem of COVID-19 spread through surface touch.

The plausible ways of functioning of the doped nano-active materials against the COVID-19 virus would be as follows:

•  As AgNPs has been reported to inhibit the replication of virus nucleotides, its main mechanism being virulent, it binds to electron donor groups such as sulphur, oxygen, and nitrogen commonly found in enzymes within the microbe. This causes the enzymes to be denatured, thus effectively incapacitating the energy source of the cell and leading the microbe to die quickly.
•  The cationic silver (Ag+) or QUATs might work to inactivate the SARS-CoV-2 by interacting with its surface (spike) protein S based on its charge like it works in HIV, hepatitis viruses, etc.

As NANOVA HYGIENE+TM omniphobic antimicrobial coating shows complete disablement of various pathogenic bacteria already and further on the basis of available scientific supports, we are of the opinion that the present formula should work against a broad spectrum of viruses as well. Initial antiviral test of NANOVA HYGIENE+TM has been performed using MS2 Bacteriophage (Poliovirus), small non-enveloped RNA virus of the family Leviviridae. The results show antiviral efficacy of 99.9 percent in just 2 hours of contact with the surface as per global standard AATCC 100-2012.

Further, the antiviral test is in process to establish its efficacy on the inactivation of COVID-19 on different surfaces to stop the secondary spread from various surfaces to living cells through touch. Once validated, it has numerous applications virtually for all surfaces like fabric (masks, gloves, doctor’s coats, curtains, bed sheets), metal (lifts, door handles, knobs, railings, public transport), wood (furniture, floors and partition panels), concrete (hospitals, clinics, and isolation wards), and plastics (switches and kitchen and home appliances) and potentially could save many lives.

For more information, please contact:
Dr. Swapan Kumar Ghosh,Director,Nova Surface-Care Centre Pvt. Ltd.
Mobile No: +91-9833237749
E-mail: swapan.ghosh@nsccindia.com