In vivo estimation of water diffusivity in occluded human skin using terahertz reflection spectroscopy. Issue 2 (26th November 2018)

• Record Type: Journal Article
• Authors: Sun, Qiushuo; Stantchev, Rayko I.; Wang, Jiarui; Parrott, Edward P. J.; Cottenden, Alan; Chiu, Tor‐Wo; Ahuja, Anil T.; Pickwell‐MacPherson, Emma
• Is Part Of: Journal of biophotonics. Volume 12:Issue 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-11-26
• Subjects: in vivo imaging -- skin occlusion -- terahertz reflection spectroscopy -- water diffusivity; Photonics -- Periodicals; Optical materials -- Periodicals; Optics -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3605
• DOI: 10.1002/jbio.201800145
• Languages: English
• ISSNs: 1864-063X

Abstract

Abstract : Water diffusion and the concentration profile within the skin significantly affect the surrounding chemical absorption and molecular synthesis. Occluding the skin causes water to accumulate in the top layer of the skin (the stratum corneum [SC]) and also affects the water diffusivity. Scar treatments such as silicone gel and silicone sheets make use of occlusion to increase skin hydration. However with existing techniques, it is not possible to quantitatively measure the diffusivity of the water during occlusion: current methods determine water diffusivity by measuring the water evaporated through the skin and thus require the skin to breathe. In this work, we use the high sensitivity of terahertz light to water to study how the water content in the SC changes upon occlusion. From our measurements, we can solve the diffusion equations in the SC to deduce the water concentration profile in occluded skin and subsequently to determine the diffusivity. To our knowledge, this is the first work showing how the diffusivity of human skin can be measured during occlusion and we envisage this paper as being used as a guide for non‐invasively determining the diffusivity of occluded human skin in vivo. Abstract : By exploiting in vivo terahertz reflection spectroscopy and skin models, this work develops a method to determine water diffusivity in occluded human skin for the first time. Dynamic water concentration and stratum corneum thickness changes upon occlusion are also tracked quantitatively. This work helps study the barrier function of the stratum corneum and will provide a new quantitative measure for use in skin studies.