Physicists in Arizona State University have devised a novel laser technique to destroy bacteria and viruses implicated in blood-borne diseases like AIDS, without damaging human cells. The researchers say that the new technique may also prove helpful in reducing the spread of hospital infections such as MRSA.
Describing the new technology in the Institute of Physics' Journal of Physics: Condensed Matter, the researchers discussed how pulses from an infrared laser could be fine-tuned to discriminate between problem microorganisms and human cells.
Current laser treatments such as UV are indiscriminate and can cause ageing of the skin, damage to the DNA or even skin cancer. These treatments are not 100 per cent effective.
Femtosecond laser pulses, through a process called Impulsive Stimulated Raman Scattering (ISRS), produces lethal vibrations in the protein coat of microorganisms, thereby destroying them.
The researchers have revealed that the effect of the vibrations is similar to that of high-pitched noise shattering glass. They have undertaken experiments to show that the coherent vibrations excited by infrared lasers with carefully selected wavelengths and pulse widths do no damage to human cells, most likely because of the different structural compositions in the protein coats of human cells vis-a-vis bacteria and viruses.
Professor K. T. Tsen from Arizona State University said: "Although it is not clear at the moment why there is a large difference in laser intensity for inactivation between human cells and microorganisms such as bacteria and viruses, 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."
The researchers say that Femtosecond lasers may find immediate application in hospitals as a way to disinfect blood supply or biomaterials, and for the treatment of blood-borne diseases such as AIDS and Hepatitis.