Long-term germ resistance possible with new antimicrobial coatings

Researchers say a new antimicrobial coating that combines copper and silver colloids with anti-adhesive surface properties will provide long-term germ resistance. The abrasion-resistant coatings reportedly offer a long-term effect that kills germs reliably while preventing germs from becoming established on the surface.

Developed by researchers at the INM - Leibniz Institute for New Materials, the coatings could be used in hospitals, kitchens, air-conditioning and ventilation systems, and in food preparation and the manufacture of packaging materials. The coatings are particularly suitable for use on large and solid surfaces, on door handles and on textiles.

“The new development combines two properties, which means the presence of germs and fungi on these surfaces is zero,” explained Carsten Becker-Willinger, head of the Nanomers Program Division. Silver or copper colloids which gradually release germicidal metal ions into the environment are incorporated in the coating.

“The metal colloids are only a few nanometres in size, but their particular ratio of size to surface area produces a distinctive long-term effect. The ‘consumption’ of metals to metal ions is then so low that the coating can be effective for several years.”

The coatings’ long-term effect will also be increased by the high abrasion resistance. Since the surface of the coating is anti-adhesive, neither dead nor fresh germs can adhere to the surface, the researchers say. As a result, the coating prevents the formation of an extensive biofilm.

The material can be applied to a range of substrates such as plastic, ceramic and metal using conventional techniques such as spraying and dipping. It can be cured thermally or photochemically. Selective variation of the individual components allows the developers to react to the particular and different needs of potential users.

The researchers proved the double microbicidal and biofilm-inhibiting action using the standardised ASTM E2 180 test process.

The research was conducted as part of the EU-sponsored CuVito project. The developers are now looking at using copper colloids and copper ions as well as silver, which they hope will make other applications possible.