Cosmetics & Toiletries: What is this new imaging technique?
Wang: Multiphoton microscopy, sometimes called two-photon microscopy. Our first objective was to evaluate this technique for the field of skin aging. The second objective was to develop a new algorithm or methodology to better characterize the process of skin aging.
C&T: How does it work?
Wang: We measure z-stacks of multiphoton microscopy images taken from the surface and deep dermis layer of the skin. [Editor’s note: in microscopy terms, z-stacks are calculated, three-dimensional representations of a sample derived noninvasively from optical sections of a specimen.]
These volumetric images are collected via two channels: two-photon fluorescence and harmonic generation. This allows us to look at the fiber orientation distributions in the deeper dermis layers of the skin. Using a new algorithm we developed, we can then visualize how aligned (or not) collagen and elastic fibers are in the skin, and how new products affect this arrangement.
C&T: What insights can you share from your work?
Wang: Aged skin showed a more single-dominant [less uniform] elastic fiber orientation, whereas younger skin had a more multi-dominant [uniform] arrangement. Interestingly, collagen fibers in aged vs. younger skin did not look much different.
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