E-Tattoos: Toward Functional but Imperceptible Interfacing with Human Skin

This review article offers an exhaustive exploration of e-tattoos, which are ultrathin, skin-soft wearable electronics that enable noninvasive and comfortable lamination on human skin. It covers their materials, structures, manufacturing processes, properties, functionalities, applications, and remaining challenges, with the potential to revolutionize telemedicine, mobile health, and human-machine interactions.

• A comprehensive review of e-tattoos, from materials to applications.
• Classification of e-tattoo functionalities including sensing and treatment.
• Discussion of energy harvesting and storage for e-tattoos.
• Outlines strategies for wireless e-tattoo system integration and future opportunities.

This is a review article that systematically explores the field of e-tattoos. It summarizes the properties of human skin, discusses materials and manufacturing for e-tattoos, classifies their functionalities, and considers system-level integration and energy solutions.

The review synthesizes the state of the art in e-tattoo technology, highlighting their potential for noninvasive physiological and psychological monitoring. It identifies key challenges and future directions for the field, aiming to guide further research and development.