Development of Novel Dermatologic Applications of in vivo Fourier Transform Infrared Molecular Spectroscopy.

Skin conditions exert an extremely large burden on the global society and health services worldwide, being the 4th greatest contributor to all non-fatal diseases. However, with overlapping pathologies and the sheer volume of skin conditions that can afflict skin, there can be difficulty in correct diagnosis, which subsequently impacts successful treatment. Fourier transform infrared spectroscopy (FTIR) is an analytical technique which can provide structural information on the stratum corneum (SC), the outermost layer of the skin. Changes within the SC are present in a wide range of skin diseases with different patho-mechanisms and so its rapid characterization provides an opportunity to help distinguish, better understand, and monitor these conditions. This thesis outlines the development of an optimised protocol for in vivo analysis of skin with a novel 3-bounce-2-pass attenuated total reflection (ATR) scanning interface, fitted to a handheld spectrometer. The use of in vivo infrared spectroscopy for the study of dermatological conditions involves the characterisation of chemical species associated with physiological structures within the SC, and how these relate to disease physiopathology and pathogenesis. It was found that ATR-FTIR has the potential to be utilised as a non-invasive multi-faceted diagnostic tool for clinical application in the identification of dry-skin disease risk, monitoring dehydration in infants and characterisation of skin barrier dysfunction due to disease pathogenesis or in response to irritants. ATR-FTIR was also utilised as a means to assess the efficacy of topical dermo- cosmetic products and their impact on skin barrier function and health. Enhanced knowledge of the impact of topical products on SC structure will aid in directing future product development to lessen the burden skin conditions have on health services and society as a whole.