Interview: “Strong potential demand for hygienic antimicrobial coatings

You have invented a new wall paint that is found to be effective against human coronaviruses and SARS-CoV2 as well. Could you please describe how the paint works against viruses?

Aristoteles Nikolakopoulos: Our R&D team developed a novel hygienic functional coating, the “Vairo Healthcare Technology”. It is the first paint based on this technology, suitable for the protection and decoration of indoor wall surfaces. Our novel technology beneficially increases the defence against virus transmission over the painted surfaces and inhibits the bacteria growth on them, helping retain the painted indoor surfaces less contaminated from pathogens, without further use of disinfectants. Although viruses do not grow on non-living surfaces, last year’s studies showed that they can remain viable or infectious for several days or weeks.

The technology uses composites with properly encapsulated silver ions into inorganic matrices and other booster components. It drives to controlled release of actives not only in wet but in dry conditions as well (splash simulating testing). Additionally, the functional wall paint with this technology unfolds a slippery properly modified hydrophilic coating with almost zero contact angle hysteresis on vertical surfaces and offers by this way a larger dynamic surface of contact which proves inhospitable for viruses and bacteria. Our technology affects viruses by destroying the spike protein and lipid membrane of enveloped viruses and the capsid protein coat of non-enveloped ones making them non-functional.

We decided to perform a real antiviral activity testing against SARS-CoV2, when we saw in structural modelling comparisons that the spike protein structure of this virus has some degree of similarity to well-known Type B human infective corona virus (OC43) but finally is closer to SARS-CoV1. As a conclusion from our studies SARS-CoV2 was a difficult virus to fight against.

Which methods and protocols have been used to evaluate your biocidal claims against viruses and bacteria? Are they conformed with the international standards? What about the authority’s role during product’s notification – registration?

Nikolakopoulos: We followed well recognised test methods based on standards ISO 21702:2019, ISO 22196:2011 and OECD proposed practices for testing efficacy of biocide treated articles (ENV/JM/MONO (2018) 20:2019). Beside these we did not make tests only in high humidity but also in more demanding dry conditions, based on splashes of contaminated liquids.

The actives we use are under evaluation according to EU 528/2012 (BPR) but listed accordingly in Article 95. This means that the procedure can be different in between Member States. This adds complexity but in most cases the authorities perceive their role to align with best anti-Covid-19 practices.

Functional coatings often possess their feature over a limited time. How long is the function effective in your wall paint?

Nikolakopoulos: The function remains effective as long as the integrity of the paint film is maintained. The novel functional wall paint engineered with a built-in surface protection technology which offers a luxurious eggshell durable finish, easy to clean properties, excellent wet scrub resistance and superior resistance to common cleaners, detergents, and disinfectants. Additionally, the controlled release of silver actives supports the long-term activity. Having all these benefits in hands, we tested the residual antiviral and antibacterial activity after an accelerated wash-scrub test using the procedure of ISO 11998 with excellent results, in both wet and dry conditions testing protocols described in OECD Guidance Document.

How often is it necessary to re-apply the paint on the wall to keep the function on high level?

Nikolakopoulos: If we consider the new normal of the pandemic and post-pandemic period, we could easily say that most interior buildings are going to be renovated more often to secure a safer and more hygienic indoor environment. This challenge led us to develop our novel antiviral-antibacterial paint.

We are offering a more sustainable solution with less maintenance and prolonged renovation times. As an indication, we could say that in a hospital where the operating rooms and intensive care areas are renovated once per year with an antibacterial paint to obtain high hygienic conditions, now our technology offers a solution for renovating every two years also with added antiviral and not only antibacterial activity.

Is there potential to combine different functionalities with a hygienic paint, such as electrically conductive paint etc.?

Nikolakopoulos: Silver is a well-known metal which is used in electrically conductive paints, but a high amount needed and this causing a grey coloration and colour restrictions. It is always a challenge and a headache to combine functionalities. Most of the times, one must judge the pros and cons. Our technology is built up with an open structure to fit with other requested added value functionalities.

The wall paint is for indoor use, such as residential building, public buildings (hospitals, schools, administration etc.). Will it remain limited to these applications?

Nikolakopoulos: Our R&D scientists are very proud to have developed this advanced functional paint technology, using high engineered tailor-made polymers, novel antimicrobials and production processes. We are looking forward to offering a real added value solution, by applying our technology in several indoor paint products for different substrates as well.

Is there potential to formulate coatings featuring this function in other areas as wall paints, as for instance in the transport segment?

Nikolakopoulos: Our novel antimicrobial technology could be used in multi-surface nonresidential interior coatings. The key factor will be the smart development of the polymer matrix and the achievement of the controlled release of actives to obtain long term antiviral activity. We can see a strong potential demand for hygienic antimicrobial coatings in the next coming post-pandemic years.