Real-time, High-resolution, In Vivo Characterization of Superficial Skin With Microscopy Using Ultraviolet Surface Excitation (MUSE)

Abstract

Background: Skin care products make up the largest part (36%) of the cosmetic market globally, of which the United States plays the largest role. In 2015, approximately 115 billion USD was spent globally on skin care products. Skin care products, in contradistinction to pharmaceuticals, are not strictly regulated by the FDA. A key factor for evaluation of a skin care product or topical drug is skin barrier function and effect on super cial skin. Thus, it is critical to have quantitative and qualitative methods to study the effects of skin care products on skin barrier and the super cial skin. Currently, no imaging method exists that can evaluate and track super cial skin changes visually in real-time.

Objective: To report using a novel imaging modality, Microscopy using Ultraviolet Surface Excitation (MUSE), to provide real-time, high- resolution, in vivo characterization of super cial skin and moisturizing properties of topical moisturizer, and to highlight key bene ts of using MUSE to visualize the super cial skin and serve as an excellent complementary tool to current quantitative methods.

Methods and materials: The methodology of MUSE is based upon two main principles inherent to ultraviolet (UV) light and uorescent staining agents. In this study, the author's (JJ) index ngertip was imaged using the MUSE instrument without and with moisturizer.

Results: Dermatoglyphics of the fingertip consists of ridges (cristae super ciales) and grooves (sulci super ciales) proved to be straightforward to visualize at high resolution. Desquamation of superficial corneocytes and opening of an acrosyringium (the most superficial portion of eccrine ducts) were visualized in high-resolution. Post-application of a moisturizer, a uniform layer of moisturizer could be seen superficial to the corneocytes along the ridges and CONCLUSIONS: Real-time, high-resolution, in vivo characterization of super cial skin and moisturizing properties of moisturizer using MUSE is feasible. Its utility can be enhanced with downstream quantification using imaging software. <em>J Drugs Dermatol. 2016;15(11):1344-1346.</em>.

FIGURE 1.

Grayscale MUSE images of the fingertip without moisturizer (A) and with moisturizer (B); original magnification × 10. In (A), dermatoglyphics of the fingertip consists of ridges (cristae superficiales) and grooves (sulci superficiales) proved to be straightforward to visualize at high resolution. Desquamation of superficial corneocytes (asterisk) and opening of an acrosyringium (the most superficial portion of eccrine ducts, arrow) were visualized in high-resolution. In (B), a uniform layer of moisturizer could be seen superficial to the corneocytes along the ridges and grooves, and indicating that the superficial skin was well-moisturized.