In-vivo Nail Measurements by Using Opto-Thermal Radiometry and Condenser TEWL Methods

P Xiaoab, LI Ciorteab, H Singha, EP Bergb and RE Imhofab

aFaculty of ESBE, London South Bank University, 103 Borough Road, London SE1 0AA, UK

bBiox Systems Ltd, 103 Borough Road, London SE1 0AA, UK

Email: xiaop@lsbu.ac.uk

Abstract

Human nail is a skin appendage that is made of keratin, and nail diseases affect many people in their everyday life. Water content and water diffusion coefficient of nails are two key parameters in drug permeation studies through nail tissue [1,2]. However, to measure water content and water diffusion coefficient of in-vivo human nails is very difficult. We have developed a new method for in-vivo human nail characterization by using opto-thermal transient emission radiometry (OTTER) [3] and condenser-chamber TEWL (trans-dermal water loss) method – AquaFlux [4]. With OTTER, we can measure nail water content, nail water concentration depth profiles, as well as topically applied solvent penetration through nail. With AquaFlux, we can measure nail transonychial water loss (TOWL). Combining the water content results with TOWL results, we can get the water diffusion coefficient of nail. Measuring the water diffusion coefficients of nail at different nail water concentration levels can also yield information on how nail diffusion coefficients change with water content. We will present the theoretical background, and experimental results on water concentration depth profile in nail, TOWL and hydration results at different point on the surface of same finger nail, TOWL and hydration results of different finger nails, as well as topically applied solvent penetration through nail.

References

[1]               B Forslind, M Lindberg, Skin, Hair, and Nails: Structure and Function, Taylor & Francis; ISBN-10: 082474313X, (2007)

[2]               D. A. R. de Berker, J. André and R. Baran, Nail biology and nail science, Int J Cosmet Sci, Vol 29 Issue 4, 241 – 275, 2007.

[3]               P Xiao, H Packham, X Zheng, H Singh, C Elliott, EP Berg and RE Imhof, “Opto-Thermal Radiometry and Condenser-Chamber Method for Stratum Corneum Water Concentration Measurements”, Appl. Phys. B, 86, 715-719, (2007).

[4]               R E Imhof, M E P De Jesus, P Xiao, L I Ciortea and E P Berg, Closed-chamber TEWL measurement:- microclimate, calibration and performance, Int J Cosmet Sci, Vol 31, Issue 2, 97-118, 2009.