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Proceedings Paper

Pulsewidth-dependent nature of laser-induced DNA damage in RPE cells
Author(s): Rebecca M. Hall; Randolph D. Glickman; Benjamin A. Rockwell; Neeru Kumar; Gary D. Noojin
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Paper Abstract

Ultrashort pulse laser radiation may produce cellular damage through unique mechanisms. Primary cultures of bovine retinal pigment epithelial (RPE) cells were exposed to the out put of a Ti:Sapphire laser producing 30 fs (mode-locked) pulses, 44 amplified fs pulses, or continuous wave exposures at 800 nm. Laser exposures at and below the damage threshold were studied. DNA damage was detected using single cell gel electrophoresis (comet assay). Unexposed (control) cells produced short tails with low tail moments. In contrast, all laser-exposed cells showed some degree of DNA fragmentation, but the size and shape of the resulting comets differed among the various modalities. CW-exposed cells produced generally light and relatively compact tails, suggesting fewer and larger DNA fragments, while mode-locked laser exposures (30 fs pulses) resulted in large and diffuse comets, indicating the DNA was fragmented into many very small pieces. Work is continuing to define the relationship of laser pulsewidth and intensity with the degree of DNA fragmentation. These results suggest that DNA damage may result from multiple mechanisms of laser-cell interaction, including multiphoton absorption.

Paper Details

Date Published: 9 July 2001
PDF: 8 pages
Proc. SPIE 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical, (9 July 2001); doi: 10.1117/12.434700
Show Author Affiliations
Rebecca M. Hall, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Randolph D. Glickman, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Benjamin A. Rockwell, Air Force Research Lab. (United States)
Neeru Kumar, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Gary D. Noojin, The Analytical Sciences Corp. (United States)

Published in SPIE Proceedings Vol. 4257:
Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical
Donald Dean Duncan; Donald Dean Duncan; Steven L. Jacques; Peter C. Johnson; Peter C. Johnson, Editor(s)

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