title: Indocyanine green and trypan blue: intracellular uptake and extracellular binding by human retinal pigment epithelial cells.
abstract: OBJECTIVE
  To examine the intracellular uptake and extracellular binding of indocyanine green (ICG) and trypan blue (TB) by human retinal pigment epithelium (RPE) cells in vitro at clinically relevant concentrations.
  
  
  METHODS
  Human RPE cells (ARPE19 cells) were exposed to 0.01%, 0.05%, and 0.25% ICG or 0.06%, 0.15%, and 0.25% TB for 15 seconds, 30 seconds, and 5 minutes, and the dye concentrations taken up by the cells were evaluated by spectrophotometric analysis.
  
  
  RESULTS
  ICG was significantly taken up by ARPE19 cells after exposure to 0.05% for 5 minutes, 0.01% for 30 seconds, and 0.25% ICG for 15 seconds, whereas TB was not taken up by RPE cells under the conditions in this study.
  
  
  CONCLUSIONS
  ICG is bound and taken up by RPE cells at concentrations lower than clinically used, and TB is not. Understanding the effects of dyes on ocular tissues leads to more effective and safer dye-assisted vitrectomy protocols, although the experimental setting is different from the clinical situation.
authors: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. takamoto-tky@umin.ac.jp
authors: Hiroyo
authors: H
authors: Hirasawa
authors: Yasuo
authors: Y
authors: Yanagi
authors: Yasuhiro
authors: Y
authors: Tamaki
authors: Yuji
authors: Y
authors: Inoue
authors: Kazuaki
authors: K
authors: Kadonosono
mesh_terms: D001692:Biological Transport / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004396:Coloring Agents / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007208:Indocyanine Green / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding; D013997:Time Factors; D014343:Trypan Blue / Q000378:metabolism*
chemical_list: D004396:Coloring Agents; D014343:Trypan Blue; D007208:Indocyanine Green