1. Novel and Rapid Method for Quantification of Stratum Corneum Disruption by Adhesive Wound Dressings Magnus S. Ågren¹, Åsa Rosqvist² and Maria Werthén² ¹ Department of Surgery K, Bispebjerg Hospital, Copenhagen University Hospital, Copenhagen, Denmark, and ²Mölnlycke Health Care AB, Gothenburg, Sweden Background Stratum corneum is the outermost layer of the skin Stratum corneum maintains the water and electrolyte homeostasis, and protects from entrance of micro-organisms and toxic agents Stratum corneum comprises layers of keratinized corneocytes Materials and methods Patients 10 (7 females) healthy volunteers Aged 20-61 years (41 ± 4 years, mean ± SEM) Dressing adhesives tested Allevyn Adhesive (Smith & Nephew) Biatain Adhesive (Coloplast) Cellosorb Adhesive (Urgo) DuoDERM Extra Thin (ConvaTec) Mepilex Border (Mölnlycke Health Care) Tielle (Johnson & Johnson) Fig. 1. Test adhesive patches applied to the lower leg. Dressings were covered with Tubifast. Keratin proteins account for at least 80% of the corneocyte mass Frequent changes of adhesive dressings can damage the skin barrier due to removal of corneocytes [1] Transepidermal water loss (TEWL) is the gold standard for the indirect non- invasive measurement of disruptions of the skin barrier function but is cumbersome and show high variability. Treatment Dressing adhesives randomized to 6 positions on posterior lower leg (Fig. 1) Dressings applied and removed every second to third day for 11 days 1.5-mm discs of used adhesives 2.100 µl 1 M NaOH added 3.After 2 hours, 100 µl 1 M HCl added 4.Protein determined by the Lowry assay (Bio-Rad) Protocol for protein extraction and determination [2] Extraction and analyses were carried out in 96-well plates (Fig. 2) Results Corneocyte removal, measured indirectly as protein, varied among the different dressing adhesives over time (Fig. 3). The constant rate in the Mepilex Border group most likely reflects the basal steady-state desquamation. Dressing adhesiveTotal protein (µg/cm 2 ) Mepilex Border 850 ± 20 Allevyn Adhesive1050 ± 40 Tielle1160 ± 100 Biatain Adhesive1200 ± 120 Cellosorb Adhesive1460 ± 80 DuoDERM1650 ± 90 References 1.Zillmer R, Ågren MS, Gottrup F, Karlsmark T. Biophysical effects of repetitive removal of adhesive dressings on peri-ulcer skin. J Wound Care 2006; 15: 187-191. 2. Dreher F, Modjtahedi BS, Modjtahedi SP, Maibach HI. Quantification of stratum corneum removal by adhesive tape stripping by total protein assay in 96-well microplates. Skin Res Technol 2005; 11: 97-101. Fig. 3. Corneocyte removal measured as protein content of used dressing adhesive (mean ± SEM). Conclusions The method presented here was simple, fast and precise in quantification of adherent corneocytes to the adhesives of wound dressings. The six examined dressing adhesives can be ranked according to their ability to remove corneocytes from skin as follows: Mepilex Border < Allevyn < Tielle = Biatain < Cellosorb < DuoDERM These data support earlier studies measuring stratum corneum damage by the TEWL technique [1]. Aim To evaluate the potential of estimating the amount of stratum corneum removed by the different types of adhesives of dressings by protein analysis. Cumulative corneocyte removal was lowest with Mepilex Border and highest with DuoDERM (Table I). Fig. 2. 96-well plate for protein measurement of extracts. Table I. Total stratum corneum removal, measured as cumulative protein, by dressing adhesives over the 11-day experimental period arranged in ascending order (mean ± SEM). Acknowledgment This work was made possible by a research grant from Mölnlycke Health Care AB.