The objective of this work was to determine the pH gradient profile across hairless mouse stratum corneum (SC) using ratiometric laser scanning confocal microscopy imaging and direct pH measurement with a flat surface electrode. Dual-emission ratiometric imaging used the fluorophore, carboxy seminaphthorhodafluor-1, which displays a pH-dependent shift in its emission spectrum. The assay developed was unsuccessful, however, because (i) the pK(a) of seminaphthorhodafluor (≃7.5) makes it insufficiently sensitive to the normal pH gradient (4-7.4) across mammalian SC, and (ii) the unexpectedly high buffering capacity of the skin precluded a meaningful calibration of the system. In the second method, pH measurements with a flat surface electrode were recorded as the hairless mouse SC was progressively tape stripped. In the superficial SC, the pH remained relatively constant (≃5.9); further removal of the barrier resulted in a steady increase in pH to ≃7. In conclusion, improved methodology is clearly required to characterize precisely the pH profile across the SC.

Original languageEnglish
Pages (from-to)110-113
Number of pages4
JournalJournal of Investigative Dermatology Symposium Proceedings
Issue number2
Publication statusPublished - 31 Dec 1998


  • Barrier function
  • Confocal microscopy
  • Skin pH
  • Stratum corneum

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Biology
  • Dermatology
  • Cell Biology


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