Recent Advances in Skin‐Mounted Electronics

摘要

The skin, the largest organ of the human body, is characterized by its softness, stretchability, and multifunctionality. Being mechanically flexible and elastic, it plays critical roles in protection, sensation, and response to external stimuli. These unique properties have inspired the development of skin-mounted electronics—lightweight, soft, and stretchable devices capable of acquiring physiological and environmental data. This research area holds significant promise for various domains, including healthcare, robotics, and human–machine interfaces. The skin is also a highly complex system. Take the sense of touch as an example. As early as the 19th century, mechanoreceptors such as Pacinian corpuscles[1] and Merkel cells[2] were discovered, marking the beginning of somatosensory research. After more than a century, the 2021 Nobel Prize in Physiology or Medicine was awarded to Professors David Julius and Ardem Patapoutian for their discoveries of temperature and touch receptors. Patapoutian identified two mechanically activated ion channels, Piezo1 and Piezo2, elucidating the molecular bases for mammalian cells to sense mechanical force. These findings have significantly advanced our understanding of mechanosensation and spurred innovations in skin-mounted electronics. For instance, mimicking the 3D architecture of Merkel cells and Ruffini endings, researchers have developed electronic skins with force- and strain-sensing components arranged in 3D configurations, enabling decoupled detection of normal force, shear force, and strain.[3] Such systems allow for simultaneous modulus/curvature measurements during tactile interactions. Another group has replicated the neural network of the somatosensory system by integrating pressure sensors, ring oscillators, and ion-gel transistors to create artificial mechanoreceptors. These devices can process multiple pressure inputs and even drive robotic actuators, such as inducing oscillatory motion in a cockroach leg.[4] Drawing inspiration from biological skin, researchers are exploring innovations in materials, device design, fabrication techniques, and wireless communication for next-generation skin-mounted electronics. In this special issue, we have included reviews and reports from researchers across different disciplines mentioned above. Wireless solutions are crucial for enhancing the functionality and usability of skin-mounted devices. Jeong et al. (article number 202400884) provide a comprehensive review of short- and long-range wireless communication technologies, along with tether-free power solutions, including integrated energy sources and energy harvesting methods. These advancements enable real-time remote health monitoring while improving user comfort and versatility. Further exploring specific applications of wireless technology, Yu et al. (article number 202500184) discuss inductor-capacitor (LC)-based sensors, which use passive resonant circuits for wireless operation. These sensors, coupled with external readers via magnetic induction, eliminate the need for internal power sources, making them ideal for intracranial pressure monitoring, intraocular pressure sensing, and tumor microenvironment analysis. Wu et al. (article number 202400950) leverage triboelectric nanogenerators to develop a contactless motion-detection system, enabling 3D motion classification for wireless human-machine interfaces. Innovative fabrication methods are essential for producing high-performance skin-mounted electronics. Seo et al. (article number 202400979) introduce a photothermal approach for fabricating sub-50 µm polymer stencil masks using UV laser processing. This method overcomes challenges in mask reproducibility while maintaining cost and time efficiency. Zhu et al. (article number 202400983) employ electrohydrodynamic (EHD) printing to deposit silver nanowire inks on ultrathin polyimide substrates. Unlike conventional inkjet printing, EHD printing avoids nozzle clogging and achieves