2.2.1. Skin hydration by Corneometer

Skin hydration is an important feature of skin samples used in experiments. Skin hydration measurements were conducted using a Corneometer CM825 mounted on a combination Derma unit SSC3 (Courage + Khazaka electronic GmbH, Cologne, Germany). This commonly used measurement probe is based on measurement of the electrical capacitance of the skin surface (uppermost 20 μm). Thus, the stratum corneum hydration is indirectly determined and obtained on an arbitrary scale, as the electrical capacitance depends on the skin's water content. ¹⁹ Measurements were performed in triplicate to obtain mean values ± SD.