Review of Advances in the Measurement of Skin Hydration Based on Sensing of Optical and Electrical Tissue Properties

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 19; p. 7151
• Main Authors: Gidado, Iman M, Qassem, Meha, Triantis, Iasonas F, Kyriacou, Panicos A
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 21.09.2022; MDPI
• Subjects: biosensors; Eczema; electrical; Hydration; Light levels; Lipids; Measurement; Measurement techniques; Mechanical properties; Moisture content; NIRS; Physical properties; Review; Sensors; Skin; Skin diseases; skin hydration; skin optics; Spectrum analysis; stratum corneum; Wearable computers; United Kingdom
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22197151

The presence of water in the skin is crucial for maintaining the properties and functions of the skin, in particular its outermost layer, known as the stratum corneum, which consists of a lipid barrier. External exposures can affect the skin’s hydration levels and in turn, alter its mechanical and physical properties. Monitoring these alterations in the skin’s water content can be applicable in clinical, cosmetic, athletic and personal settings. Many techniques measuring this parameter have been investigated, with electrical-based methods currently being widely used in commercial devices. Furthermore, the exploration of optical techniques to measure hydration is growing due to the outcomes observed through the penetration of light at differing levels. This paper comprehensively reviews such measurement techniques, focusing on recent experimental studies and state-of-the-art devices.