18 April 2005 Optical monitoring of thermal effects in the retina during laser exposure
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Proceedings Volume 5688, Ophthalmic Technologies XV; (2005); doi: 10.1117/12.591068
Event: SPIE BiOS, 2005, San Jose, CA, United States
Abstract
Fast and non-invasive detection of cellular stress is useful for fundamental research and practical applications in medicine and biology. Using Light Scattering Spectroscopy we extract information about changes in refractive index and size of the cellular organelles. Particle sizes down to 50nm in diameter can be detected using light within the spectral range of 450-850 nm. We monitor the heat-induced sub-cellular structural changes in human RPE cells and, for comparison, in transfected NIH-3T3 cells which express luciferase linked to the heat shock protein (HSP). Using inverse light scattering fitting algorithm, we reconstruct the size distribution of the sub-micron organelles from the light scattering spectrum. The most significant (up to 70%) and rapid (20sec) temperature-related changes can be linked to an increase of refractive index of the 160nm sized mitochondria. The start of this effect coincides with the onset of HSP expression. This technique provides an insight into metabolic processes within organelles larger than 50nm without exogenous staining and opens doors for non-invasive real-time assessment of cellular stress, which can be used for monitoring of retinal laser treatments like transpupillary thermo therapy or PDT.
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Georg Schuele, Philip Huie, Dimitri Yellachich, Fanni Molnar, Caitlin O’Conell-Rodwell, Edward Vitkin, Lev Perelman, Daniel Palanker, "Optical monitoring of thermal effects in the retina during laser exposure", Proc. SPIE 5688, Ophthalmic Technologies XV, (18 April 2005); doi: 10.1117/12.591068; http://dx.doi.org/10.1117/12.591068
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KEYWORDS
Light scattering

Scattering

Refractive index

Particles

Transmission electron microscopy

Mie scattering

Proteins

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