Development of Miniature Optical Instrumentation for Skin and Epithelial Tissue

Abstract

Throughout this thesis we have sought to construct cost effective, miniature and portable imaging systems to assess a selection of physical parameters re- lated to the the integrity of human skin and epithelial tissue, in vivo. While these technologies can be used for any skin site we, specifically, aim to develop novel non-invasive instrumentation for the diagnosis of menopausal atrophy at point of care. Post-menopause, the outer epithelial layer, begins to thin (at- rophy) and anatomic changes are observed in the vaginal wall cell structure, hydration level, blood oxygenation, epidermal thinning and elasticity (Chapter 2). Yet, despite the profound impact on well-being, there is a significant lack of quantitative tools to measure the epidermal barrier function, or level of atrophisation, in outer skin surfaces and vaginal mucosa. Recent advances in optical microscopy, together with progress in miniature optical components, permit visualisation of living skin tissues. To this purpose we seek to employ existing methodologies such as oximetry, microscopy and imaging modalities within a low cost multifunctional instrument. Particularly we describe the potential use of laser speckle light scattering for surface roughness measure- ment with its limitations and, using numerical models, discuss the parameters that dictate speckle pattern formation. We extend this discussion to rough skin surface with additional bulk scattering from underlying volume tissue (Chapter 3). Through this series of studies we apply our work in laboratory experiments. A range of bench-top instruments were built to measure skin spectral characteristics and additionally a novel single point laser speckle sys- tem towards the measurement of in vivo skin roughness across a selection of volunteers (Chapter 4). In collaboration with industrial partners (Procter and Gamble (P&G) and Lein Applied Diagnostics) we developed a mock up pro- totype towards a novel, non-invasive optical device to quantify patient skin integrity (Chapter 6). This is achieved through a multidisciplinary approach, with novel developments in miniature optical manufacturing and assembly pro- cess (Chapter 5). For future work we outline our protocols, material cost and ways to facilitate these miniature diagnostic instruments for various research and clinical settings.