Face masks are our best frontline defence tools against the spread of infectious diseases like COVID-19. It is known that face masks offer only a physical barrier and cannot destroy pathogens. Also, a few studies indicate that the coronavirus remains active on face masks for up to a week. Would it not be advantageous if a mask not only stopped the virus from entry but also destroyed it?
In the rapid response to unprecedented challenges posed by the present pandemic, globally, scientists are looking at different options to enhance the protection offered by face masks.
In a step towards contributing to this endeavour, a team of researchers from the Institute for Stem Cell Science and Regenerative Medicine, inStem, Bengaluru, has developed a germicidal fabric called G-fab. The novel material is effective in deactivating enveloped viruses (to which the current coronavirus belongs) and bacteria upon contact with it. Furthermore, the team has translated the technology and used G-fab to manufacture face masks.
Fortified from within
These innovative antimicrobial masks are manufactured in collaboration with M/s. Color Threads Pvt Ltd, Tiruppur, Tamilnadu, and marketed under the brand name G99+. With the mask having passed all necessary regulatory and testing procedures, it indicates a potential to destroy bacteria and viruses — including the SARS-CoV-2 — on the mask surface within three minutes.
When it comes to enhancing the efficiency of a face mask, an obvious line of thought is to provide an additional filter. Or, to coat the outer layer of the mask with antimicrobial agents that can destroy the infectious agents on the surface.
However, G99+ is made by choosing a different method: fortifying the fabric with antimicrobial agents. “We have developed novel molecules that can deactivate viruses and bacteria upon contact. The molecules are covalently attached to the fibres of cotton fabric. This makes the fabric antimicrobial,” says Dr Praveen Vemula, lead scientist of the project. Dr Vemula is an innovator and entrepreneur at inStem and is instrumental in translating many research studies into commercial products in India, the USA and France.
The antimicrobial molecules belong to what are called quaternary ammonium salts. These salts are ionic and carry a positive charge. When these charged particles come in contact with the outer membrane of the microbes, they interact with it, penetrate the inner layers, and rip them apart. This action drains the cellular components, inflicting damage to the microbes. “The G-fab technology thus not only traps the pathogens but also destroys them in a few minutes, providing advanced protection to the user,” says the scientist.
Strength in every fibre
The team has demonstrated the efficacy of the germicidal fabric in killing a broad spectrum of bacteria (gram-positive and gram-negative) and viruses such as lentivirus, Sendi virus, coronavirus SARS-CoV-2, and human influenza viruses (H1N1).
The pandemic resulted in huge demand for face masks, which come in several varieties in the market: disposable surgical mask, an N95 aspirator, or simple homemade cotton face covering. All of them can only arrest the microbes on their surface, none capable of destroying them. “G99+ addresses this unmet need. It offers additional protection to the user, while also reducing the burden on landfills contributed by the huge number of disposable masks,” avers the innovator.
The team focused on incorporating a simple technique to develop the germicidal fabric, ensuring a seamless translation into a commercially viable product. The process involved dipping cotton fibres into the specially made formulation containing antiviral molecules and other additives. Then, subjecting the fibres to curing under specified temperature by the end of which, the antiviral molecules get incorporated into the fibres.
The quaternary salts react with the cellulose in the cotton fibres and chemically bind to them. “The salts are not loosely present in the fabric. Instead, they become a part of the cotton fibre, “explains Dr Vemula. The process ensures that the wearer does not accidentally inhale any chemicals from the fabric, he adds.
With minimal refinements, Color Threads Pvt Ltd accommodated the technology into their production supply chain, while also ensuring the mask passed the necessary international testing standards. The product is certified by the South India Textile Research Association, Coimbatore.
As the situation demands
The reusable mask comprises three layers: the outer two layers are germicidal, and the innermost layer is of cotton (for the comfort of the wearer). Also, between the three layers is a pocket-like slit that can hold an insert-type add-on filter. The wearer has the option of using the insert for additional protection in dense atmospheres like malls or crowded areas. The filter is also made from G-fab, to trap and destroy the pathogens that overload the first two layers.
Moreover, the insert lasts for ten consecutive uses and does not require washing. “The germicidal fabric denatures the viral particles. The remains are just remnants of the pathogens which are incapable of causing infection,” clarifies Dr Vemula.
The mask is a reusable one, and after every three uses requires a wash by soaking in plain hot water for ten minutes and hung to dry. The mask retains its efficiency for up to 30 washes, thereby lasting for 90 uses. Although mild detergents can be used to remove heavy soiling, Dr Vemula cautions that “Washing the mask every time with detergents is not recommended. The harsh chemicals in the soap can react with the salts. The life of the mask will degrade, thereby reducing the germicidal property in the fabric.”
The next obvious question that arises is, how affordable are these masks? Currently, the manufacturers price each G99+ mask at ₹249, which comes with one free insert. Each additional insert costs another ₹50. Since each mask lasts for quite a few times’ use, it becomes an economically viable option, says Dr Vemula.
The effect of the mask on the SARS COV-2 has been validated by the Department of Biotechnology (DBT) and the Rajiv Gandhi Centre for Biotechnology (RBCB)
The manufacturers are working out with the distributors and e-commerce platforms to make the mask available in a week or two, said Dr Vemula.
(The original story on the site was updated with additional information about its validation and availability)