Applying nano-coatings to protect from viral infections

Simon Mercer, director at Signo-Nanocare, looks at how antimicrobial technology applied through nano-coatings can be used to reduce the transfer of hospital acquired infections (HAI). 

While the pandemic is far from being over, we are all welcoming the chance that vaccines have given us to be able to meet, socialise and return to some form of normality. For many, this will mean the hope that routine surgeries put off over the last twelve months will happen and attending a doctor’s surgery or hospital and picking up an infection is not quite as life threatening as it has been perceived by many in the last year. 

The pandemic has sharpened the focus on the transmission of infections via the hand-surface-hand transfer route in the public’s mind, one which has always been taken seriously in healthcare. While the COVID cleaning regimes continue, they are also impacting on other transient microbes such as MRSA, Staphylococcus and Streptococcus infections that can be as deadly as SARS-CoV-2. 

The annual data collated by the Nuffield Trust on the number of HAI, such as Clostridioides difficile and MRSA, show that they have remained at a stubbornly constant level since 2013/14, with only minor changes in the number of hospital and community onset cases. Of equal concern, the annual data on the Escherichia coli have shown a consistent low level of infection with hospital cases, however cases of community on-set have risen dramatically since 2015/16, contributing to a sharp overall increase.  

There is much debate as to the achievable level that HAI can be held to and ‘zero tolerance’ may be seen as a lofty aspiration; after all, the eradication of an infectious disease has only been achieved with Smallpox. However, the constant challenge remains in healthcare settings to reduce the number of HAI and with many (MRSA and C. Difficile) there is a need to break through the consistent plateau of cases, and to affect the next level of reduction.

While the existing infection prevention measures have brought about the reductions seen today, further decreases can be achieved by using new technologies in surface protection. 

The performance requirements of the “optimum” type of antimicrobial surface technology are outlined in a recent briefing paper ‘Smart surfaces to tackle infection and antimicrobial resistance’ by Imperial College London (ICL) Institute of Molecular Science and Engineering (IMSE). The paper highlights ten ideal properties for an antimicrobial surface treatment as: -

• Safety - the surface must remain safe for regular contact with patients, staff and visitors.
• Healthcare economics – the surface must represent good value healthcare.
• Simple application technology – the surface must remain antimicrobial for months/years. 
• Rapid antimicrobial activity- antimicrobial activity occurs rapidly. 
• Prevention of biofilm formation – must have the ability to prevent biofilm creation or disrupt existing ones.
• Compatibility with current cleaning and disinfection products – any extensively used chemicals should not interfere with the antimicrobial action. 
• Retention of activity with low-level soiling – the presence of organic matter or dirt should not interfere with the surface activity.
• Does not promote clinically-significant resistance or reduce susceptibility – there is theoretic risk of the development of resistance or susceptibility to the surface.
• Sporicidal activity – C. Difficile spores present a particular challenge to antimicrobial surfaces so the solution should be effective against this particular pathogen. 

A multi-disciplined team drawing on skills from the materials, engineering and science backgrounds working with nano-coating technology has developed an antimicrobial nano-coating that kills bacteria, viruses and yeast pathogens on surface contact along with meeting all ten of the ‘ideal properties’ put forward by the ICL IMSE briefing paper. 

The antimicrobial nano-coating, when applied yearly to a surface, creates an invisible layer of nano-spikes that ‘puncture’ the cells’ outer wall, physically killing and rendering it untransmissible through surface contact. The physical nature of the kill ensures that the coating is non-mutagenic and does not aid antibiotic resistance.

Antimicrobial nano-coatings have enabled a breakthrough in the permanence of anti-microbial effect that allows healthcare settings to break the plateau floor of hospital acquired infection rates with a constant background kill of pathogens. 

Signo-Nanocare launched Liquid Guard in 2019, a long-term antimicrobial nano-coating that has been proven effective after one application against MRSA, Clostridioides difficile, Escherichia coli, Staphylococcus, Streptococcus as well as SAR CoV-2 for twelve months and longer on virtually any surface.