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Research persons: Professor K. T. Tsen

Location: Arizona State University, United States

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Physicists in Arizona State University have
designed a revolutionary laser
technique which can destroy viruses and bacteria such as AIDS
without damaging human cells and may also help reduce the spread of hospital
infections such as MRSA.
The research, published on Thursday November 1 in the Institute
of Physics’ Journal of Physics: Condensed Matter, discusses how pulses
from an infrared laser can 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, at
worst, skin
cancer, and are far from 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 effect of the vibrations is similar
to that of high-pitched noise shattering glass.
The physicists in Arizona 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.”
Femtosecond lasers could 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.
About Researcher:
Kong-Thon Tsen
Professor
Ph.D., Purdue University
Home Department - Physics 
Areas of Study - Experimental Solid State Physics and biophysics 
Class Pages - PHY 113, PHY 114, PHY 131
phone: 480-965-5206
fax: 480-965-7954
email: tsen@asu.edu
Background Tsen’s research interest focuses on the interaction of light with solid state and biological systems in particular, on the use of ultrafast laser sources to elucidate novel electron transport phenomena, dynamical properties of lattice vibrations in low-dimensional and nanostructure semiconductors as well as microscopic mechanisms in biological systems such as viruses, bacteria and cells. He has more than 160 publications and has edited 4 books in the area of ultrafast phenomena in semiconductors. Books edited: (1) "Ultrafast Phenomena in Semiconductors" published by Springer-Verlag (New York,2001). (2) "Ultrafast Physical Processes in Semiconductors", published by Academic Press as the book Volume #67 in the series – “Semiconductors and Semimetals”, edited by R.K. Willardson and E.R. Weber(New York, 2001). (3) “Ultrafast Dynamical Processes in Semiconductors”, published as the book Volume #92 in the series – Topics in Applied Physics, by Springer-Verlag (Heidelberg, 2004). (4) “Non-equilibrium Dynamics of Semiconductors and Nanostructures”, published by CRC press Inc. (New York, 2005)