Recent Press Releases

Fine-tuning lasers to destroy blood-borne diseases like AIDS

IOP

PR43(07)

Wed, 31 October 2007

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.

ENDS

1.  For further information or a full pdf of the journal article, contact:

Joe Winters, Press Officer,

Institute of Physics, 76 Portland Place, London. W1B 1NT

Telephone +44 (0)20 7470 4815.

E-mail: joseph.winters@...

2. The paper "Selective inactivation of microorganisms by near-IR femtosecond laser pulses" will be available from Thursday 1 November in the Institute of Physics' 'Journal of Physics: Condensed Matter', Vol. 19, 472201.

3.  The Institute of Physics is a scientific membership organisation devoted to increasing the understanding and application of physics. It has an extensive worldwide membership (currently around 34 000) and is a leading communicator of physics with all audiences from specialists through government to the general public. Its publishing company, IOP Publishing, is a world leader in scientific publishing and the electronic dissemination of physics.

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Selective inactivation of micro-organisms with near-infrared femtosecond laser pulses

http://www.iop.org/EJ/abstract/0953-8984/19/47/472201

K T Tsen et al 2007 J. Phys.: Condens. Matter 19 472201 (7pp)   doi:10.1088/0953-8984/19/47/472201

	PDF (222 KB) | HTML | References

K T Tsen¹, Shaw-Wei D Tsen², Otto F Sankey¹ and Juliann G Kiang^3
1 Department of Physics, Arizona State University, Tempe, AZ 85287, USA
² Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA
³ Scientific Research Department, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20889, USA
E-mail: tsen@...

Abstract. We demonstrate an unconventional and revolutionary method for selective inactivation of micro-organisms by using near-infrared femtosecond laser pulses. We show that if the wavelength and pulse width of the excitation femtosecond laser are appropriately selected, there exists a window in power density that enables us to achieve selective inactivation of target viruses and bacteria without causing cytotoxicity in mammalian cells. This strategy targets the mechanical (vibrational) properties of micro-organisms, and thus its antimicrobial efficacy is likely unaffected by genetic mutation in the micro-organisms. Such a method may be effective against a wide variety of drug resistant micro-organisms and has broad implications in disinfection as well as in the development of novel treatments for viral and bacterial pathogens.

Print publication: Issue 47 (28 November 2007)
Received 17 September 2007, in final form 17 October 2007
Published 1 November 2007

PDF (222 KB) | HTML | References

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