Skin‐Adhesive, ‐Breathable, and ‐Compatible Nanopaper Electronics for Harmonious On‐Skin Electrophysiological Monitoring

Abstract On‐skin electronics, which offers an interface for extracting electrophysiological signals from skin, is intensively investigated using electrodes mounted on flexible substrates. Despite numerous efforts toward substrate design to optimize user comfort, substrates with skin‐adhesion, skin‐breathability, skin‐compatibility, mechanical endurance, sterilizability, sustainability, and biodegradability remain desirable candidates for human‐ and environment‐friendly on‐skin electronics. To this end, a wood‐derived cellulose nanofiber paper (denoted nanopaper) with customized porous nanostructures is developed in this study. The customized porous nanopaper enables water‐assisted deformation for skin‐conformability, thereby realizing outstanding skin‐adhesion force, along with high skin‐breathability and compatibility, superior to those of conventional substrates reported for on‐skin electronics. By mounting gold electrodes on the porous nanopaper and adhering them to human skin, the real‐time monitoring of electroencephalogram, electromyogram, and electrocardiogram for diagnosing the human physiological state is successfully achieved. Furthermore, the gold‐electrode‐mounted porous nanopaper affords unique characteristics including durability against skin deformation, reusability, and even sterilizability, owing to its high mechanical endurance, and thermal stabilities. Thus, the as‐prepared porous nanopaper serves a fascinating platform for human‐ and environment‐harmonious on‐skin electronics

Stretchable broadband photo-sensor sheets for nonsampling, source-free, and label-free chemical monitoring by simple deformable wrapping

Chemical monitoring communicates diverse environmental information from industrial and biological processes. However, promising and sustainable systems and associated inspection devices that dynamically enable on-site quality monitoring of target chemicals confined inside transformable and opaque channels are yet to be investigated. This paper designs stretchable photo-sensor patch sheets for nonsampling, source-free, and label-free on-site dynamic chemical monitoring of liquids flowing inside soft tubes via simple deformable surface wrapping. The device integrates carbon nanotube–based broadband photo-absorbent thin films with multilayer-laminated stretchable electrodes and substrates. The patterned rigid-soft structure of the proposed device provides durability and optical stability against mechanical deformations with a stretchability range of 70 to 280%, enabling shape-conformable attachments to transformable objects. The effective use of omnidirectional and transparent blackbody radiation from free-form targets themselves allows compact measurement configuration and enhances the functionality and simplicity of this scheme, while the presenting technology monitors concentrations of arbitrary water-soluble chemicals

Fully Transparent, Ultrathin Flexible Organic Electrochemical Transistors with Additive Integration for Bioelectronic Applications

Optical transparency is highly desirable in bioelectronic sensors because it enables multimodal optical assessment during electronic sensing. Ultrathin (90%) and high transconductance (≈1 mS) in low-voltage operations (<0.6 V). Further, electroencephalogram acquisition and nitrate ion sensing are demonstrated in addition to the compatibility of simultaneous assessments of optical blood flowmetry when the transparent OECTs are worn, owing to the transparency. These feasibility demonstrations show promise in contributing to human stress monitoring in bioelectronics