Fig. 4.
3D OrbiSIMS data showing the ion intensity variation as function of skin depth for various compounds, highlighting the subtle changes in skin chemistry that can be detected using this method. The primary ion beam was Ar3000+.The ion intensities have been normalized to the total ion count. (A) Data demonstrating the permeation of an exogenous compound, the palmitoyl oligopeptide Pal-GHK (C30H55N6O5+), into the SC layer of ex vivo human skin tissue. The SC–epidermal boundary has been determined and approximated with a dotted vertical line, based on the ion intensity variation of the intrinsic phosphocholine molecular ion (C5H15NO4P+). The profiles have been compressed using a running average method (100 data points) and the skin depth is represented by total ion dose. (B) Data showing the normalized intensity for the Pal-GHK molecular ion (C30H55N6O5+) as a function of tape strip number, produced from 3D OrbiSIMS analysis of human tape strips collected in vivo following application of a commercially relevant formulation. The graph contains data from 15 sequential tape strips collected from both treated and untreated sites and is represented as the average and SE of 3 different volunteers (n = 3).