The water in skin, particularly in stratum corneum, the outmost skin layer, is very
important. However, to measure it is very difficult. OTTER (Opto-thermal
transient emission radiometry), AquaFlux, and Epsilon are three novel
technologies specifically developed by our research group for such measurements.
This thesis describes the latest development of the technologies. The main focus is
to develop a state of the art OTTER data acquisition and data analysis software
programme based on Pico Technology. The new software programme offers a
range of benefits, such as faster sampling rate, better ADC resolutions, more user
friendly interfaces, and more functions and features. The modularized dynamic
link library based approach, also means it is easier to maintain, update and expand.
With the new OTTER software programme, a multiple wavelength detection is
carried out, and an enhanced segmented least squares (SLS) fitting is proposed.
The results show that by combining multiple wavelength detection and enhanced
SLS fitting, OTTER is capable to detect different types of skin damage, and the
presence of topically applied solvents as well as depth distribution of solvents
within skin. The second main focus is skin characterization by using AquaFlux
and Epsilon, as well as other skin measurement instruments, such as Corneometer,
Moisture Checker, Hydratest Beauty Pro, and ProscopeHR2 digital microscope.
The aims are to have better understanding on the instrument performances, the
correlations between instruments, as well as skin damage assessments, and
in vitro and in vivo skin solvent penetration. The results show that the
combination of AquaFlux and Epsilon can be very useful for skin
characterizations, and the ratio of skin hydration and TEWL can be a better index
for skin barrier function. The results also show that the Epsilon capacitive
occlusion curves can be potentially used for skin damage assessments, as it can
detect both the scale of the damage, and the type of the damage. The skin solvent
penetration results show that Epsilon can be effectively used for measuring
different types of solvents, and a method to quantify solvent concentration in
skin has been developed.