Ultra-violet light is able to destroy micro organisms because of its low wave-length (10-400 nm) and high energy. The UV radiation is extremely harmful to cells because it causes thymine dimers to form in the DNA. The DNA replication mechanisms are unable to repair the dimers, this causes DNA replication to halt and then the cell enters apoptosis.
Traditional laser treatments are unable to discriminate between foreign cells and human cells. When this treatments are used not only destroy the virus or bacteria but human cells as well. The side effects of this kind of treatment include skin aging, damage to the DNA of human cells, and may also cause skin cancer. Another problem with this type of treatment is that it is not 100% effective.
There has been a recent discovery from the Arizona State University in which a laser that emits infrared pulses is able to discriminate between human and problem microorganism cells. This technology uses Femtosecond laser pulses, and through a process called Impulsive Stimulated Raman Scattering (ISRS), produces lethal vibrations in the protein coat of microorganisms, thereby destroying them. This laser is similar to the principles that work when high pitched noises shatter glass.
With this new technology the Femtosecond laser pulses use a process called impulsive Stimulated Raman Scattering which produced vibration in the protein coat of micro-organisms which destroys the viruses and bacteria without causing any damage to human cells. Only the bacterial or viral cells are destroyed because the protein coat of their cells are very different from the protein coat of human cells. However when selecting the wavelength and pulses of the laser you need to be careful to select one that will only damage/destroy the viral or bacterial cells and not the human cells as well. Otherwise you will still have similar problems that were caused by the UV laser radiation.
This new technology has many different applications. It can be used in hospitals to disinfect blood supplies as well as other bio materials. This would be very beneficial in a hospital setting because it would make sure that bio materials would be fully sterilized without have to worry about destroying the beneficial cells. Another hospital application would be to use it on infections such as MRSA. This technology can also be used for the treatment of blood-borne illnesses such as AIDS and hepatitis.
Prescott, Harley, & Klein's Microbiology Seventh Edition (Pg 142)