News-Letter

Media Credit: Eileen Huang Junior Shaw-Wei "David" Tsen was inspired by his research to study how lases affect viruses.

When junior Shaw-Wei "David" Tsen took a casual stroll in the park with his dad, he had little idea that their conversation would result in a revolutionary new antiviral treatment.

Tsen and his father, Kong-Thon Tsen, a physicist at Arizona State University, have developed a novel laser technique to destroy viruses and bacteria without damaging human cells.

The idea came from Tsen's work in immunology research at the Hopkins Kimmel Cancer Center. He was searching for a new method to sterilize blood of dangerous pathogens, including HIV and Hepatitis C.

"I had read literature on the use of microwaves to sanitize blood samples," Tsen said. "I was considering using ultrasonic vibrations to destroy the virus. However, my dad proposed that we use lasers instead."

The laser works because of resonance frequency. All molecules vibrate at an intrinsic frequency, determined by the structure of the compound and the arrangement of the atoms. Exciting the viral capsid, or outer protein coat, of a virus will cause it to break apart.

Ultrasound is mostly absorbed by the water surrounding the virus, diffusing any effect the vibrations may have on the pathogen. Ultra-Short Pulse (USP) Lasers can directly penetrate the energy-absorbing water surrounding the viruses and go straight to the pathogens themselves.

"The laser induces a dipole moment in the virus's capsid," Tsen said. "These dipole moments create a force within the virus which amplifies the coherent vibrations. As the vibrations increase, the virus becomes unstable and breaks apart."

Tsen and his father aimed a low-power USP laser into glass tubes containing bacteriophages - viruses that infect bacteria. The number of viruses within each sample plummeted after exposure to the laser.

"As you can imagine, I repeated the experiment many times just to make sure it wasn't a fluke," Tsen said.

When the father-son team was certain they were successful, they released their findings, which were published in the July 13 issue of the Journal of Physics: Condensed Matter.

Building on the idea that amplified vibrations destroy the viral capsid, Tsen and his father demonstrated that their low-power laser could selectively destroyed viruses while sparing normal human cells.

Continued...

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