In vivo intra- and inter-individual variability study of human stratum corneum by confocal Raman spectroscopy

The present research work deals with the in vivo determination of intra- and inter-individual human stratum corneum biochemical variability using confocal Raman spectroscopy. This study was carried out at three different spots on the volar forearm region of healthy human participants in the extended fingerprint and high wavenumber spectral regions. All the preprocessed spectra were compared by correlation matrices, which were calculated using Pearson's correlation coefficient (r). The results indicate that the participated volunteers in this study are homogenous with respect to the stratum corneum in the forearm region in both extended fingerprint and high wavenumber regions as there is high correlation between their Raman spectra at both intra- and inter-individual levels. This study confirms the application of confocal Raman spectroscopy as an accurate and precise technique for in vivo studies involving human skin.