Probing skin pigmentation changes with transient absorption imaging of eumelanin and pheomelanin

Dan Fu, Tong Ye, Thomas E. Matthews, James Grichnik, Lian Hong, John D. Simon, Warren S. Warren

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


As some of the most ubiquitous and biologically important natural pigments, melanins play essential roles in the photoprotection of skin. Changes in melanin production could potentially be useful for clinical diagnosis of the progression stage of melanoma. Previously we demonstrated a new method for imaging melanin distribution in tissue with two-color transient absorption microscopy. Here we extend this study to longer wavelengths and show that we are able to image melanin in fixed thin skin slices with higher signal-to-noise ratios (SNRs) and demonstrate epimode imaging. We show that both photothermal effects and long-lived excited states can contribute to the long-lived signal. Eumelanin and pheomelanin exhibit markedly different long-lived excited state absorption. This difference should enable us to map out their respective distribution in tissue samples with subcellular resolution. This technique could provide valuable information in diagnosing the malignant transformation of melanocytes.

Original languageEnglish (US)
Article number054036
JournalJournal of Biomedical Optics
Issue number5
StatePublished - 2008
Externally publishedYes


  • excited state absorption
  • melanoma imaging
  • multiphoton microscopy
  • photothermal effects
  • transient absorption
  • two-photon absorption

ASJC Scopus subject areas

  • Biomedical Engineering
  • Biomaterials
  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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