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Raman microspectroscopy of melanosomes: the effect of long term light irradiation

Anushree Saha1, Rajan Arora, Vladislav V Yakovlev

  • 1School of Medicine, Case Western Reserve University, 2085 Adelbert Road, OH 44106, USA. anushree.saha@case.edu

Journal of Biophotonics
|July 30, 2011
PubMed

Insights

Melanosomes in retinal pigment epithelium cells degrade with light exposure. Researchers used Raman microspectroscopy to measure melanosome photobleaching, determining the power threshold and rate of irreversible damage.

Area of Science:

  • Ophthalmology
  • Cell Biology
  • Spectroscopy

Background:

  • Melanosomes are organelles in retinal pigment epithelium (RPE) cells.
  • They provide photoprotection but can degrade with age or light exposure.
  • This degradation may involve photobleaching of melanin pigments.

Purpose of the Study:

  • To investigate the photochemical changes in melanosomes upon light exposure.
  • To quantify the photobleaching process and determine its parameters.

Main Methods:

  • Melanosomes were isolated from RPE cells.
  • Isolated melanosomes were exposed to green light (532 nm).
  • Chemical changes were monitored using Raman microspectroscopy.

Main Results:

  • Photochemical changes were recorded at various power levels and exposure times.
  • A model was used to fit the experimental data.
  • The threshold power and rate for irreversible photobleaching were calculated.

Conclusions:

  • Melanosomes undergo irreversible photobleaching when exposed to green light.
  • Raman microspectroscopy is effective in monitoring these photochemical changes.
  • The study provides quantitative parameters for melanosome photobleaching.

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