NMR and Intrared Spectroscopic Studies of Stratum Corneum Hydration

Mobility of Water in Human Stratum Corneum

“…Hansen and Yellin 37 proposed that water molecules bound to primary and secondary sites in SC exchange rapidly on an NMR time scale (10 À8 s), but slowly on an IR time scale (10 À14 s), making them indistinguishable by the former technique, but distinguishable by the latter. The spin-spin relaxation curves for water in hydrated SC containing 0.50-1.5 g H 2 O/g dry tissue could be fit by assuming two species of water, one (the less mobile fraction, $0.30 g H 2 O/g dry tissue) with a relaxation time t 2 of 17 ms, the other with t 2 ¼ 106 ms.…”

“…40 According to Spencer, 38 the first 0.10-0.15 g H 2 O/g dry tissue at 60% relative humidity constitutes primary bound water, although more primary binding sites are evidently exposed at high levels of hydration. 37 Thus, the BET monolayer value determined in the accompanying paper, 7 n m ¼ 0.0386 g H 2 O/g dry tissue, reflects only a fraction of the primary bound water in SC.…”

“…37,38 Both forms may be distinguished by infrared (IR) analysis, whereas NMR distinguishes only one. 37 Primary bound water is considered in the older literature to be associated with the polar functional groups of keratin and other skin proteins; 37,38 more recent accounts include the water of hydration of intercellular lipid headgroups. 6,39 The primary form is essential for SC pliability.…”

Water relations of tetrapod integument

“…While the mechanism excluding free water from the deeper cell layers of stratum corneum is not understood, it is speculated to play a role in preventing dehydration of the viable epidermis. In relatively dry conditions (18%-26% w/w), only bound water is present in the stratum corneum (Bulgin and Vinson, 1967;Hansen and Yellin, 1972;Bouwstra et al, 2003a).…”

Optical Fiber Near Infrared Spectroscopy for Skin Moisture Measurement

“…For instance, an easy measurement method of water content is essential for atopic cases (Arimoto et al, 2005). Hansen and Yellin (1972) have applied NMR and IR to determine that at water content lower than 10%, the water present was tightly bound, most likely due to the polar sites of the proteins. At water contents in between 10-40%, they found less tightly bound water and suggested it was hydrogen-bonded to the protein-bound water.…”