Facilitating in vitro Tape Stripping: Application of Infrared Densitometry for Quantification of Porcine Stratum Corneum Proteins

Infrared (IR) densitometry is a highly practical method recently proposed for protein analysis during in vivo tape stripping. However, this method has not yet been validated for the quantification of porcine stratum corneum (SC) proteins. Therefore, the aim of this study was to establish calibration curves for the analysis of adhesive tapes removed from porcine ear skin. To this end, the protein absorption (as determined via IR densitometry) was correlated with the protein content determined with the Micro BCA™ protein assay after extraction of the tapes. The obtained linear regressions confirm that IR densitometry is suitable for the quantification of not only human, but also porcine, SC proteins. The pattern of protein removal observed with porcine skin differs from that of human skin due to more pronounced corneocyte clustering and deep ‘canyons’, which necessitates specific evaluation of porcine skin samples and a working protocol that takes this into account. The presented data will facilitate future analysis of porcine SC proteins during in vitro tape stripping.