The treatment could kill viruses while preserving human cells

Current ultraviolet light laser treatments can kill micro-organisms - but cannot be used in humans as they would also damage cells in the body.

But using infrared femtosecond lasers with carefully selected wavelengths, a US team targeted viruses and bacteria without harming other cells.

The Arizona research is reported in the Journal of Physics: Condensed Matters.

The technology is called Impulsive Stimulated Raman Scattering (ISRS).

It produces lethal vibrations in the protein coat of micro-organisms, thereby destroying them. The effect of the vibrations is similar to that of high-pitched noise shattering glass.

However, the line of attack can be perfected so that the proteins which coat human cells remain unaffected.

So far experiments have been done on E. coli bacterial cells, Tobacco Mosaic Virus cells, as well as human and hamster cells.

After several attempts, the researchers found a level which "inactivates both viruses and bacteria while leaving sensitive materials such as mammalian cells unharmed".

Lead researcher Professor Kong-Thon Tsen, of Arizona State University, said: "The research so far suggests that ISRS will be ready for use in disinfection and could provide treatments against some of the worst, often drug-resistant, bacterial and viral pathogens."

Dr Jean-Yves Maillard, senior lecturer in pharmaceutical microbiology at Cardiff University, said: "This is quite an interesting technology but it's at a very preliminary stage and any application in humans is a long way off."