Posted: January 15, 2008

Bacteria drop dead on killer surfaces

(Nanowerk News) Work surfaces that kill bacteria on contact could soon be a reality in our homes and hospitals, thanks to researchers from the Curie Institute in Paris. The French group has developed a method for making surfaces bactericidal that it says is straightforward and versatile enough to be widely used.
A paper in Chemical Communications ("A new, simple approach to confer permanent antimicrobial properties to hydroxylated surfaces by surface functionalization" – free access article) describes a versatile and experimentally simple technique for fabricating highly positively charged nanometric thin films on materials bearing hydroxylated groups (e.g. alcohols or silanols) on their outmost surfaces, such as glass, silicon wafer and cellulose, conferring on them the ability to kill bacteria on contact.
Vincent Semetey and colleagues have devised a simple way to attach polymers containing quaternary ammonium groups to surfaces. Surfaces modified in this way kill any bacteria that come into contact with them.
antibacterial bandages
The technology can be used to modify any surfaces that have free hydroxyl groups, including textiles such as bandages.
'The strategies developed so far for attaching the polymers require multiple steps and the use of organic solvents, which is a strong limitation to their implementation in industry,' said Semetey. 'Our method requires just a single reaction step in water.' He added that because the polymer is bound covalently, the antibacterial activity is permanent, which is an advantage over techniques with surfaces impregnated with biocides such as silver ions.
Past experiments with similar surfaces have shown that the ammonium cations do not induce resistance in bacteria, said Semetey, a great advantage in these days of multiresistant superbugs.
The researchers say that their method can be used to modify any surfaces that have free hydroxyl groups, including glass, ceramics and some plastics. According to Semetey the technology is particularly suited to treating textiles, for example bandages.
'There is an urgent need for easy-to-apply coatings to make materials permanently bactericidal,' said Alexander Klibanov of the Massachusetts Institute of Technology, US. Himself a pioneer in the field, he said Semetey's work was timely and that the method was straightforward and could help control the spread of infections.
Semetey said that he and his group are considering several applications of their method in hospitals, and are working together on this with colleagues based at the hospital run by the Curie Institute. Furthermore, the technology has received interest from several companies.
Source: Reprinted with permission from Chemical Sciences (Danièle Gibney)
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