FIG. 1.

Skin structure. The outermost stratum is the epidermis, a stratified layer of keratinocytes; the dermis is found underneath, which consists of dense irregular connective tissues and cushions the body from stress and strain. Finally, the hypodermis is the innermost layer of the skin, mainly functioning as fat storage. (a) Schematic view. Modified image. Republished with permission from Sutterby et al., Small 16, 39 (2020). Copyright 2021 John Wiley and Sons, permission conveyed through Copyright Clearance Center, Inc.⁵ (b) Histological section. Modified image. Reprinted with permission from Mine et al., PLoS One 3, 12 (2018). Copyright 2021 Authors, licensed under a Creative Commons Attribution (CCBY) License 4.0.⁶