Nav: Home

DNA damage by ultrashort pulses of intense laser light

June 09, 2016

In a recent development, scientists at the Tata Institute of Fundamental Research report that damage to DNA can be induced by ultrashort pulses of high intensity laser light. Published in Scientific Reports, these findings have important implications in clinical conditions, especially in reducing collateral damage to tissues surrounding the real target of conventional radiotherapy.

High intensity femtosecond laser pulses were used to probe damage to aqueous DNA [1]. In propagating through the water medium, the intense light pulses cause H2O molecules to ionize and break-up, giving rise to low-energy electrons and OH-radicals. Both are responsible for producing breaks in DNA strands. Infact, earlier work carried out by the same team [2, 3] showed that OH radicals were four times more likely than electrons to produce double strand breaks in DNA.

A collaborative project between TIFR Mumbai, the Centre for Excellence in Basic Sciences, Mumbai, and Manipal University, the experiments described in this new publication utilized different incident laser energies and various external focusing conditions to establish that DNA damage occurs in two distinct regimes. Interestingly, the numerical aperture of the focusing lens (the light-gathering ability of the lens) delineates the two regimes. This permits optical control to be exercised over the extent of DNA damage by simply varying the focal length of the focusing lens.

"The experimental technique of generating, in situ, slow electrons and radicals within aqueous media has important implications in different scenarios where the effects of non-ionizing radiation need to be probed under physiologically relevant conditions," says Professor Deepak Mathur, senior scientist at TIFR Mumbai, and the lead scientist of this study.

It has been suggested that detrimental dose distributions within tissues that are irradiated by gamma radiation - one of the major difficulties in radiotherapy -- might be avoided by use of femtosecond laser induced filamentation. This is due to ultrashort laser pulses, particularly in the infrared region, being spatially confined to volumes (~125 μm3) that are much smaller than what is possible to attain using contemporary clinical radiation sources. This is important for minimising damage to non-target tissues in the vicinity.
-end-
1. J. A. Dharmadhikari, A. K. Dharamdhikari, K. C. Kasuba, H. Bharambe, J. S. D'Souza, K. D. Rathod, and D. Mathur, Sci. Reports -- in press

2. J. S. D'Souza et al., Phys. Rev. Letters 106 (2011) 118101,/p>

3. A. K. Dharmadhikari et al., Phys. Rev. Letters 112 (2014) 138105

Tata Institute of Fundamental Research

Related Dna Articles:

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.
Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.
DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.
A new spin on DNA
For decades, researchers have chased ways to study biological machines.
From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.
Self-healing DNA nanostructures
DNA assembled into nanostructures such as tubes and origami-inspired shapes could someday find applications ranging from DNA computers to nanomedicine.
DNA design that anyone can do
Researchers at MIT and Arizona State University have designed a computer program that allows users to translate any free-form drawing into a two-dimensional, nanoscale structure made of DNA.
DNA find
A Queensland University of Technology-led collaboration with University of Adelaide reveals that Australia's pint-sized banded hare-wallaby is the closest living relative of the giant short-faced kangaroos which roamed the continent for millions of years, but died out about 40,000 years ago.
DNA structure impacts rate and accuracy of DNA synthesis
DNA sequences with the potential to form unusual conformations, which are frequently associated with cancer and neurological diseases, can in fact slow down or speed up the DNA synthesis process and cause more or fewer sequencing errors.
Changes in mitochondrial DNA control how nuclear DNA mutations are expressed in cardiomyopathy
Differences in the DNA within the mitochondria, the energy-producing structures within cells, can determine the severity and progression of heart disease caused by a nuclear DNA mutation.
More DNA News and DNA Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.