Programming electronic skin with diverse skin-like properties

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-01, Vol.9 (2), p.963-973
• Main Authors: Huang, Jinjian, Liu, Ye, Chi, Xiang, Jiang, Yungang, Xu, Ziyan, Qu, Guiwen, Zhao, Yun, Li, Zongan, Chen, Canwen, Chen, Guopu, Wu, Xiuwen, Ren, Jianan
• Format: Article
• Language: English
• Subjects: Antiinfectives and antibacterials; Color; Hydrogels; Immunoregulation; Inflammation; Iron; Lactic acid; Perception; Piezoresistivity; Polyacrylamide; Reactive oxygen species; Shear thinning (liquids); Skin; Sodium lactate; Wearable technology; Wound healing; Xanthan; Xanthan gum
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta09101d

Simulating the comprehensive functions of native skin-and not simply the perception of external physical stimuli-by electronic skin (e-skin) has gathered increasing attention in the development of wearable devices and human-interactive technology. Here, we report an anti-bacterial, color-variable, ultraviolet (UV)-sensitive, shape-adaptive, and immunoregulatory e-skin based on a single- and dual-network switchable hydrogel composed of a covalent network of polyacrylamide (PAAm) and a coordinated network of xanthan gum (Xg)/iron ions [Fe( iii )]. In the presence of sodium lactate and UV exposure, Fe( iii ) could be reduced to Fe( ii ), which de-coordinated the Xg/Fe( iii ) network. During this reduction process, the e-skin realized three functions of real skin: (i) UV triggered a color change with detectable resistance alterations; (ii) reactive oxygen species (ROS) were dramatically produced to defend against pathogens; and (iii) the piezoresistant hydrogel became highly stretchable to perceive all-scale human motions. Moreover, the shear-thinning properties of Xg in the precursor solution allowed the e-skin to be printable, and the anti-inflammatory functions of de-coordinated Xg were beneficial for wound healing. In summary, this newly-developed e-skin can achieve the perception of UV and human motions. It has promising applications for irregularly-shaped body surfaces and infected wounds. Simulating the comprehensive functions of native skin-and not simply the perception of external physical stimuli-by electronic skin (e-skin) has gathered increasing attention in the development of wearable devices and human-interactive technology.