According to the latest update, over 40 million people have been infected with SARS-CoV-2, commonly known as COVID-19, and above 1.12 million deaths have been reported worldwide. Since the World Health Organization (WHO) declared a pandemic on 11th March 2020, it has spread to over 200 countries globally. But there is still no potential cure in terms of antiviral drugs or vaccines to stop any further spread and human casualty. So far, the best way one can protect himself from this highly contagious disease is by following a few WHO guidelines on preventive measures such as social distancing, using a mask to prevent the spreading of mouth and nasal air droplets, and using alcohol-based sanitizers. But this could not prevent the spread of the infection. Today, the COVID-19 pandemic has created an unprecedented stir in global public health, created a global economic slowdown, unemployment, and a rise in health complications such as severe lung damage.

More than 100 vaccines against COVID-19 are in various development stages, and around 33 vaccines are currently undergoing clinical trials. However, Russia and China have already approved one vaccine for emergency use. It is speculated that a fast-tracked vaccine could come to the market around the end of 2020 to the middle of 2021. Therefore, the world still has to face the challenges of reducing exposure to COVID-19.

• Minimize the spread of COVID-19 infection in public places like hospitals, transport, schools, worship places, stores, malls, etc.
• As the restrictions on travel and business activities have been lifted in various countries in a phased manner for the last two months, there has been an enormous surge in the number of new COVID-19-positive patients worldwide.
• With over 372 552 new cases reported on 17th October 2020 worldwide, the US, Brazil, India, Russia, Spain, and Argentina are the worst sufferers in the number of total persons positive for COVID-19.
• To develop surface disinfectants that are non-poisonous, have long-lasting effects on inhibition of virus even after repeated exposure, and are non-toxic to humans.

Anticipated Antiviral Coatings Against COVID-19

Being an enveloped virus, it is anticipated that the antiviral coatings may inactivate SARS-CoV-2 upon contact and can help prevent contamination and spread if coated on various surfaces. Coating being developed has shown potential antiviral effects and is non-toxic to any human body exposed to coating. There are various R&D and commercial activities, but few recent developments in antimicrobial coatings, especially keeping in mind the COVID-19 pandemic, have been discussed.

• At the University of Arizona (UA), a highly effective antimicrobial coating formulation has been developed. Once applied, it can help keep surfaces clear of a human coronavirus for up to 90 days and has the potential to reduce the virus by 90% in 10 minutes and by 99.9% in two hours. Charles Gerba, one of the senior investigators, thinks that it’s essential for high-use surfaces like subways and buses, prone to re-contamination.
• Nanoparticle coating developed from metal ions and polymers has shown exceptional antiviral properties recently investigated by researchers at the Ben-Gurion University of the Negev, Israel. The coating’s antiviral effects were assessed on the infectivity of HIV family member lentiviruses. It was found the surfaces coated with copper nanoparticles strongly blocked the infection of the cells by the virus. It shows copper ion’s potential in preventing surface-mediated infection, such as found in the SARS-CoV-2 pandemic spread.
• Application of another potential germicidal coating of quaternary ammonium salts on fabrics has shown good experimental results in killing bacteria or viruses, as reported at two Bengaluru-based research centers in India. The coating in solution form can be applied to masks and coats of COVID-19 frontline workers after heat treatment, helping the molecules get attached. The molecule was found to be effective against pathogens even after 25 rounds of washing. Thus the coating has the potential to enhance the quality of personal protective equipment (PPEs).
• A patentable technology known as the Duraprot has been developed by the Indian Institute of Technology, Bombay (IIT-B). The coating crosslinks antibacterial and antiviral components onto the textile’s fibers through a simple dipping process. A prerequisite as per textile guidelines, the coating is retained after several wash cycles and has been tested for 20 wash cycles at the IIT-B laboratory.
• A team led by Dr. Avinash Bajaj at the Regional Center of Biotechnology (RCB) in Faridabad, India, in collaboration with other researchers, has initiated a study to engineer virucidal coatings to prevent COVID-19 transmission. Once developed, these molecules will engineer different surfaces like glass, plastic, and textiles, including cotton, nylon, and polyester, to provide a virucidal coating that can inhibit viral transmission.
• A team of researchers at Virginia Tech (US) has reported developing and testing a novel surface coating that can inactivate the COVID-19 virus when painted on everyday objects, such as doorknobs, light switches, shopping carts, etc. The surface coating can inactivate the virus after multiple rounds of being exposed to the SARS-CoV-2 virus, and the virus was reduced to 99.9% after application on glass and steel surfaces.
• NANOVA HYGIENE+TM is a multi-surface self-sanitizing nano-coating, which was proven and tested against human coronavirus-229E (July 2020, Nelson Labs USA). FDA approved it. This coating is a composite of non-migratory QUATs and positively charged AgNPs (silver nanoparticles) as bioactive nanoparticles, which have shown antimicrobial effects on surfaces like fabrics plastics metals, and concretes.

Further, a non-toxic coating, NitroPep, was developed and patented by a group of researchers at Birmingham University. The product was developed as a new defense line against healthcare-associated infections, including MRSA, E. coli, Salmonella, and fungi, and test results show it has a killing rate of 99.9%, even after repeated exposure. NitroPep has been approved for the UK domestic market and is yet to be tested against SARS-CoV-2. The main active component is chlorhexidine, a commonly used biocide found in mouthwash and antiseptic creams. NitroPep is claimed to be more effective than existing silver and copper surface technologies.

These novel surface coatings have shown promising antimicrobial and antiviral potential. Therefore further studies on COVID-19 will strengthen the future application of these coatings for public places, trains, buses, schools malls, etc.