Affiliations: Alfred Wegener Institute Foundation for Polar and Marine Research, Am Handelshafen 12, D‐27570 Bremerhaven, Germany | Institute of Food Technology and Center of Biotechnology, Technical University of Berlin, Amrumer Str. 32, D‐13353 Berlin, Germany | Wyatt Technology Deutschland GmbH, In der Steubach 9, D‐57614 Woldert, Germany | Anatomical Institute, Department of Histology and Embryology, School of Veterinary Medicine, Bischofsholer Damm 15, D–30173 Hannover, Germany
Note: [] Address for correspondence: Prof. Dr. Lutz‐Günther Fleischer, Institute of Food Technology and Center of Biotechnology, Technical University of Berlin, Amrumer Str. 32, D‐13353 Berlin, Germany. Fax: ++49 30 314 275 18; E‐mail: l‐[email protected].
Abstract: The rheological properties of the stratum corneum of the pilot whale (Globicephala melas) were investigated with emphasis on their significance to the self‐cleaning abilities of the skin surface smoothed by a jelly material enriched with various hydrolytic enzymes. The gel formation of the collected fluid was monitored by applying periodic‐harmonic oscillating loads using a stress‐controlled rheometer. In the mechanical spectrum of the gel, the plateau region of the storage modulus G′ (<1200 Pa) and the loss modulus G″ (>120 Pa) were independent of frequency (ω=43.98 to 0.13 rad·s−1,τ=15 Pa, T=20°C), indicating high elastic performance of a covalently cross‐linked viscoelastic solid. In addition, multi‐angle laser light scattering experiments (MALLS) were performed to analyse the potential time‐dependent changes in the weight‐average molar mass of the samples. The observed increase showed that the gel formation is based on the assembly of covalently cross‐linked aggregates. The viscoelastic properties and the shear resistence of the gel assure that the enzyme‐containing jelly material smoothing the skin surface is not removed from the stratum corneum by shear regimes during dolphin jumping. The even skin surface is considered to be most important for the self‐cleaning abilities of the dolphin skin against biofouling.
