Using compact and affordable instrumentation based upon fluorescent confocal imaging we have tracked the movement
of autofluorescent compounds through skin in near real time with high temporal and spatial resolution and sensitivity.
The ability to measure the diffusion of compounds through skin with such resolution plays an important role for
applications such as monitoring the penetration of pharmaceuticals applied to skin and assessing the integrity of the skin
barrier. Several measurement methods exist, but they suffer from a number of problems such as being slow, expensive,
non-portable and lacking sensitivity. To address these issues, we adapted a technique that we previously developed for
tracking fluorescent compounds in the eye to measure the autofluorescence and the diffusion of externally applied
fluorescent compounds in skin in vivo. Results are presented that show the change in autofluorescence of the volar
forearm over the course of a week. We furthermore demonstrate the ability of the instrument to measure the diffusion
speed and depth of externally applied fluorescent compounds both in healthy skin and after the skin barrier function has
been perturbed. The instrument is currently being developed further for increased sensitivity and multi-wavelength
excitation. We believe that the presented instrument is suitable for a large number of applications in fields such as
assessment of damage to the skin barrier, development of topical and systemic medication and tracking the diffusion of
fluorescent compounds through skin constructs as well as monitoring effects of skin products and general consumer
products which may come into contact with the skin.
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