title: Real-time visualization of melanin granules in normal human skin using combined multiphoton and reflectance confocal microscopy.
abstract: BACKGROUND
  Recent advances in biomedical optics have enabled dermal and epidermal components to be visualized at subcellular resolution and assessed noninvasively. Multiphoton microscopy (MPM) and reflectance confocal microscopy (RCM) are noninvasive imaging modalities that have demonstrated promising results in imaging skin micromorphology, and which provide complementary information regarding skin components. This study assesses whether combined MPM/RCM can visualize intracellular and extracellular melanin granules in the epidermis and dermis of normal human skin.
  
  
  METHODS
  We perform MPM and RCM imaging of in vivo and ex vivo skin in the infrared domain. The inherent three-dimensional optical sectioning capability of MPM/RCM is used to image high-contrast granular features across skin depths ranging from 50 to 90 μm. The optical images thus obtained were correlated with conventional histologic examination including melanin-specific staining of ex vivo specimens.
  
  
  RESULTS
  MPM revealed highly fluorescent granular structures below the dermal-epidermal junction (DEJ) region. Histochemical staining also demonstrated melanin-containing granules that correlate well in size and location with the granular fluorescent structures observed in MPM. Furthermore, the MPM fluorescence excitation wavelength and RCM reflectance of cell culture-derived melanin were equivalent to those of the granules.
  
  
  CONCLUSIONS
  This study suggests that MPM can noninvasively visualize and quantify subepidermal melanin in situ.
authors: Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada; Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada; Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Ali
authors: A
authors: Majdzadeh
authors: Anthony M D
authors: AM
authors: Lee
authors: Hequn
authors: H
authors: Wang
authors: Harvey
authors: H
authors: Lui
authors: David I
authors: DI
authors: McLean
authors: Richard I
authors: RI
authors: Crawford
authors: David
authors: D
authors: Zloty
authors: Haishan
authors: H
authors: Zeng
mesh_terms: D003594:Cytoplasmic Granules / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008543:Melanins / Q000378:metabolism*; D018613:Microscopy, Confocal; D012867:Skin / Q000166:cytology* / Q000378:metabolism*
chemical_list: D008543:Melanins
keywords: melanin granule; multiphoton microscopy; reflectance confocal microscopy; skin