Zapping viruses with light

[Guest guest]

Interesting that this sould post today, I just found this article

about light being used to kill viruses.

A father-son research team working from separate laboratory benches

across the country has discovered a new use for lasers - zapping

viruses out of blood.

The technique, which holds promise for disinfecting blood for

transfusions, uses a low-power laser beam with a pulse lasting just

fractions of a second.

s Hopkins University student Shaw-Wei Tsen says it was

during a stroll in the park with his father that the idea was born.

Tsen, an immunology researcher in the laboratory of T.C. Wu at

Hopkins' Kimmel Cancer Center, sought a new method to rid isolated

blood of dangerous pathogens, including the viruses HIV and hepatitis

C. He says current techniques using UV irradiation and radioisotopes

can leave a trail of mutated or damaged blood components.

Using ultrasonic vibrations to destroy viruses was one possibility,

but his father, Kong-Thon Tsen, a laser expert at Arizona State

University, had a better idea: Lasers, unlike ultrasound, can

penetrate energy-absorbing water surrounding the viruses and directly

vibrate the pathogen itself.

The researchers aimed a low-power laser with a pulse lasting 100

femtoseconds (10-13 second) into glass tubes containing saline-

diluted viruses that infect bacteria, also known as bacteriophages.

The amount of infectious virus within each cube plummeted 100- to

1000-fold after the laser treatment. " I had to repeat the experiment

several times to convince myself that the laser worked this well, "

says the younger Tsen.

His laser is different from those emitting a continuous beam of

visible light. " Our laser repeatedly sends a rapid pulse of light and

then relaxes, allowing the solution surrounding the virus to cool

off, " Tsen says. " This significantly reduces heat damage to normal

blood components. "

Building on the idea that vibration wrecks a virus' outer shell, the

scientists found that their low-power laser selectively destroys

viruses and spares normal human cells around them, while stronger

beams kill almost everything.

Father and son speculate that laser vibrations could destroy drug-

resistant and -sensitive viruses alike.

Wu says that the technique his student developed " could potentially

be used to control communicable diseases by giving infusions of laser-

treated blood products. "

The scientists published their results in the July 13 issue of the

Journal of Physics: Condensed Matter. They will continue their

studies using different viruses.

Says Wu, " We believe this work on bacterial viruses is promising, but

the real test will be with more serious pathogens like HIV and

hepatitis. "

http://www.hopkinsmedicine.org/