Pulsewidth-dependent nature of laser-induced DNA damage in RPE cells

R. M. Hall, R. D. Glickman, B. A. Rockwell, N. Kumar, G. D. Noojin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


Ultrashort pulse laser radiation may produce cellular damage through unique mechanisms. Primary cultures of bovine retinal pigment epithelial (RPE) cells were exposed to the output 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.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsD.D. Duncan, S.L. Jacques, P.C. Johnson
Number of pages8
StatePublished - 2001
EventLaser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical - San Jose, CA, United States
Duration: Jan 21 2001Jan 24 2001


OtherLaser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical
Country/TerritoryUnited States
CitySan Jose, CA


  • Comet assay
  • DNA
  • Laser bioeffect
  • Multiphoton
  • RPE cell
  • Ultrashort pulse

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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