27 June 2002 Microbubble dynamics around melanosomes irradiated with microsecond pulses
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Proceedings Volume 4617, Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical; (2002) https://doi.org/10.1117/12.472539
Event: International Symposium on Biomedical Optics, 2002, San Jose, CA, United States
The origin of cell damage due to irradiation of the retina with microsecond laser pulses is most likely the disintegration of retinal pigment epithelial cells, which is caused by the formation of microbubbles around the strongly absorbing melanosomes within the cell. In order to get a more detailed understanding of the laser tissue interaction in the retinal pigment epithelium we irradiated a suspension of porcine melanosomes, which served as a model system, by a frequency doubled Nd:YLF laser emitting at 527 nm. We used pulse durations of 500 ns and 3.5 microsecond(s) . The formation of microbubbles around isolated melanosomes was imaged directly on a microscopic level by fast flash light photography. Near threshold radiant exposure for bubble formation, we found transient bubbles with diameters below 1 micrometers and lifetimes below 500 ns. Applying super-threshold irradiation stable bubbles with diameters up to 7 micrometers and lifetimes in the millisecond time regimen were observed. This can be explained by production of stable gas inside the melanosome due to laser heating.
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Joerg Neumann, Joerg Neumann, Ralf Brinkmann, Ralf Brinkmann, } "Microbubble dynamics around melanosomes irradiated with microsecond pulses", Proc. SPIE 4617, Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical, (27 June 2002); doi: 10.1117/12.472539; https://doi.org/10.1117/12.472539

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