The world is struggling with the challenge posed by the growing pandemic of COVID-19. Unquestionably, we are passing through a critical phase of our lives. Anything offering immunity, protection, and wellness are needed. If clothes can protect us and mitigate the virus is obviously desirable. Textiles provide a large hosting surface area for bacteria
and viruses, benefiting their carryover. Antiviral fabrics offer protection from numerous Viruses such as Coronavirus (229E)Influenza Avian flu, Swine flu, and Respiratory Syncytial Virus (RSV), etc. During this stage, an antiviral surface could play the biggest role in cutting down on the spread of a virus.
What are Antiviral fabrics? And how they work?
Antiviral fabrics are farther exploiting the capacities of the antimicrobial surface. Antiviral properties can be imparted on to the treated fabrics with various antimicrobial agents such as silver particles by applying chemical finishes with additives with exhaust and padding methods, coatings, and nano applications. An antimicrobial surface contains an antimicrobial agent that inhibits the ability of microorganisms to grow on the surface of the material. Antiviral treatments could miraculously change regular clothes into viral resistant fabrics, and viruses and bacteria can be made ineffective within minutes. And such fabrics may be valuable in both medical and non-medical use.
It is a proven fact that there are certain metals and compounds that have broad-spectrum of microbial efficacy. Silver, copper, titanium dioxide, and zinc oxide are known for the fact since ages. For instance, silver can kill the virus by denaturing proteins and disrupting membranes. Antiviral fabrics are treated with certain chemical finishes that are capable of inactivating the virus by altering the capsid (protein layer). The major methods explored in textiles are of Silver synthesis which is the physical and chemical methods. When a negatively charged virus comes in contact with the positively charged silver treated fabric a redox reaction1 takes place and changes occur in virus structure in different ways (according to the virus family) as a result virus becomes inactive. There are many silane quats and silver-based technologies available in the market which all are having anti-viral properties. However, they will work in a time span of 2-24 hours. Most of the published literature describes the antiviral activity of silver or gold nanoparticles against enveloped viruses, with both a DNA or an RNA genome.2The major difference between antiviral and antimicrobial clothes is the time span in which the virus becomes ineffective. One antimicrobial claimed fabric may also be antiviral but it will take a lengthier period to inactive the virus.
- Chemical finishes:
Swiss textile innovation company HeiQ Materials AG has made Viroblock, which is a combination of silver & vesicle technology: the silver technology attracts the oppositely charged viruses and binds permanently to their sulfur groups. Subsequently, fatty spherical vesicle technology (Liposomes) helps to deplete the viral membrane of its cholesterol content in minutes. Therefore the silver can destroy the virus rapidly. It has two components, a very small amount of silver, which is there to trap the virus. Viruses are negatively charged and silver is positively charged, so the virus gets trapped. All these enveloped viruses have a cholesterol layer in their membrane. The liposome drains out this cholesterol in just a couple of minutes. This cholesterol gives the pliability/flexibility to the virus. Once it is gone the membrane cracks open and the silver attacks the RNA and destroys it. This whole action takes place in 2-5 minutes.3The finish is stable for 30HL, ISO 6330.
HealthGuard® Australia is a different company who has a similar product with different chemistry(Quaternary Ammonium Compound )HealthGuard® AMIC is a concentrated anti-microbial and anti-enveloped virus (includes Novel Coronavirus – COVID-19) finish specially formulated for use in the textile industry4
Viral Off Polygiene Technology Sweden is another chemical finish for viral resistant fabrics, claims “Products treatedwithViraloff® willhold99% fewer viruses in 2 hrs. Treated products are tested with ISO18184 tests against viruses (like Influenza, Corona, Hepatitis). The active ingredient is a reaction mass of titanium dioxide and silver chloride. Antiviral testing performed at the Beijing Institute of Microbiology and Epidemiology.5
- Coatings /Nanoparticles applications
Sonoviatech Israel: Sonovia Ltd from Israel has developed an anti-pathogen fabric that could be used in masks to stop the spread of coronavirus. Sonovia’s tech is using a novel method of coating which is binderless, the process is cavitation, they call it ultrasound-based, the antimicrobial coating. The technology mechanically infuses metal oxides nanoparticles onto textiles during an ultrasonic-assisted impregnation process with the specialized chemical compound turning the textiles into highly effective blocks against bacteria and fungi6 The tests in the Micro spectrum lab (Weipu Jishu) in Shanghai confirm that the patented, the anti-viral fabric is effective against the novel coronavirus. The company claims the fabric is safe and tested to be effective even after being washed 90 times.7
Multilevel antimicrobial polymer (MAP-1) coating: The coating reportedly prevents microbial adhesion on a surface by using the special blend of antimicrobial polymers, effectively killing “99.9% of bacteria and viruses.”The coating was developed by a team led by professor Yeung King-lun, of the Department of Chemical and Biological Engineering and the Division of Environment and Sustainability. According to the university: “MAP-1 coating provides lasting protection and surface disinfection against microbial contamination. This product is designed for use on different surfaces including metals, concrete, wood, glass, plastics as well as fabrics, leathers, and textiles without changing the materials’ appearance and tactile feel.8
Virustatic shield UK: The Virustatic Shield is a unique Viruferrin™ coating. “Viruferrin ™ contains lactoferrin, a naturally-occurring protein which is an immensely important part of the human innate immune system and has decades of peer-reviewed research behind it. Independent scientists from VisMederi laboratory at the University of Siena found the Viruferrin™ protein compound inhibits SARS-CoV-2, the virus strain that causes the current COVID-19 pandemic.9 Carrington Textiles and its main manufacturing facility in the UK, Pincroft, have teamed up with a UK biotech firm that developed a snood with technologies that prevent and protect against airborne virus transmission.10
Promethean Particles UK: Copper is also well known for its antimicrobial properties, Promethean Particles, UK is exploring antiviral effects with copper nanoparticles designed for use in fabrics and Personal Protective Equipment (PPE) for the healthcare sector. in conjunction with the Mexican research institute, CIQA, and textile trade association, NWTexNet, fibres embedded with copper nanoparticles manufactured by scientists from Promethean, have been sent to independent laboratories in the US and UK for anti-viral testing to ISO standards. If certified, it could open the door to the manufacture and supply of nonwoven fabrics and Personal Protective Equipment (PPE), such as garments, face masks, hats, uniforms and bed linen, which is resistant to viruses – such as the coronavirus that causes Covid-19 – and will offer much needed improved protection for frontline health workers.11
Many Indian textile companies are offering Antiviral fabrics using various technologies such as Arvind12, Vardhman, Ginni filaments, Siyaram, etc.
Application: These clothes will be useful in medical textiles such as Face masks, aprons, visitor’s gowns, Apron, Apparel, Bedsheets, wipes, curtains, drapes, etc.
Stability and testing of efficacy: The finishes are stable up to 20-30 home launderings. Test methods for Antiviral fabrics are different from antibacterial fabrics, Successfully passing AATCC TM100 or AATCC TM147 has no bearing on whether a product will prevent or protect against the COVID19 virus. While an excellent predictor of functionality, if someone promises or alludes that their textile-related product will defend against COVID19 solely because it passed one or both of these methods, please be cautious.13
ISO 18184:2019(en)is the the test for determination of the antiviral activity of textile products.14, And ISO 20743:2013(en) is for determination of antibacterial activity of textile products15
- A redox reaction proceeds with one chemical species gaining electrons and the other losing them.https://en.wikipedia.org/wiki/Redox