Epidermal self-powered sweat sensors for glucose and lactate monitoring

Sweat could be a carrier of informative biomarkers for health status identification;therefore,wearable sweat sensors have attracted significant attention for research.An external power source is an important component of wearable sensors,however,the current power supplies,i.e.,batteries,limit further shrinking down the size of these devices and thus limit their application areas and scenarios.Herein,we report a stretchable self-powered biosensor with epidermal electronic format that enables the in situ detec-tion of lactate and glucose concentration in sweat.Enzymatic biofuel cells serve as self-powered sensing modules allowing the sweat sensor to exhibit a determination coefficient(R2)of 0.98 with a sensitivity of 2.48 mV/mM for lactate detection,and R2 of 0.96 with a sensitivity of 0.11 mV/μM for glucose detection.The microfluidic channels developed in an ultra-thin soft flexible polydimethylsiloxane layer not only enable the effective collection of sweat,but also provide excellent mechanical properties with stable performance output even under 30%stretching.The presented soft sweat sensors can be integrated at nearly any location of the body for the continuous monitoring of lactate and glucose changes during normal daily activities such as exercise.Our results provide a promising approach to develop next-generation sweat sensors for real-time and in situ sweat analysis.

Origami-inspired folding assembly of dielectric elastomers for programmable soft robots

Origami has become an optimal methodological choice for creating complex three-dimensional(3D)structures and soft robots.The simple and low-cost origami-inspired folding assembly provides a new method for developing 3D soft robots,which is ideal for future intelligent robotic systems.Here,we present a series of materials,structural designs,and fabrication methods for developing independent,electrically controlled origami 3D soft robots for walking and soft manipulators.The 3D soft robots are based on soft actuators,which are multilayer structures with a dielectric elastomer(DE)film as the deformation layer and a laser-cut PET film as the supporting flexible frame.The triangular and rectangular design of the soft actuators allows them to be easily assembled into crawling soft robots and pyramidal-and square-shaped 3D structures.The crawling robot exhibits very stable crawling behaviors and can carry loads while walking.Inspired by origami folding,the pyramidal and square-shaped 3D soft robots exhibit programmable out-of-plane deformations and easy switching between two-dimensional(2D)and 3D structures.The electrically controllable origami deformation allows the 3D soft robots to be used as soft manipulators for grasping and precisely locking 3D objects.This work proves that origami-inspired fold-based assembly of DE actuators is a good reference for the development of soft actuators and future intelligent multifunctional soft robots.