In vivo measurement of DNA in the skin using confocal Raman microspectroscopy: determination of the stratum corneum thickness and superficial microbiome
Maxim E. Darvin,1 Jin Song Ri,2 Se Hyok Choe,2 Johannes Schleusener,1 Jürgen Lademann,1 Chun Sik Choe,2
1 Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany
2 Kim Il Sung University, Pyongyang, Democratic People's Republic of Korea
Abstract
The stratum corneum (SC), the uppermost layer of the epidermis, consists of the enucleated corneocytes embedded in the structured lipid matrix. SC thickness can be determined using confocal Raman microspectroscopy (CRM) by analyzing the gradient of water concentration and the concentration of lipids with long-chain carbon backbone (free fatty acids and ceramides). In the present in vivo study, a new method for the determination of SC thickness based on the determination of the DNA concentration profile by CRM is presented. The basic idea of this method is that corneocytes do not contain DNA molecules, which can be found first in the nuclei of keratinocytes in the stratum granulosum layer. The results obtained show that it is possible to calculate SC thickness using the DNA depth profile, which is comparable to the values of SC thickness calculated using the water depth profiles (ANOVA test p = 0.77) and the lipid depth profile (ANOVA test p = 0.74). This new method offers the possibility to measure SC thickness using the DNA depth profile in case the water or lipid profile analyses are influenced by, for instance, a topically applied formulation. The increase in DNA concentration in the superficial SC depth of 0–2 μm is related to the DNA presence in the cutaneous microbiome, showing how deep the superficial microbiome is in the SC.
Speaker
Maxim Darvin
Charité-Universitätsmedizin Berlin
Germany
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