Fig. 1. A 10-μm-thick nanomesh-reinforced hydrogel for long-term, continuous electrophysiological monitoring.

(A) Schematic illustration of the design concept of PU nanomesh–reinforced hydrogels. (B) Ultrathin hydrogel used for long-term, continuous electrophysiological monitoring, such as ECG, EMG, MCV, EOG, EEG, ABR, and VEP. (C) Cross-sectional SEM image of the ultrathin hydrogel attached on an anodisc substrate. Scale bar, 10 μm. (D) A photograph of a suspended ultrathin hydrogel holding a large amount of water. The tensile stress (σ) can be calculated by dividing the body force of the liquids by the thickness and circumference of the ultrathin hydrogels: $\mathrm{\sigma }=\frac{\mathit{\text{Pr}}}{2t}$ , where the P, r, and t are the applied pressure of the water, the radius of the curvature, and the thickness of the ultrathin hydrogels, respectively (42). Scale bar, 1 cm. (E) A photograph of the peeling-off of an ultrathin hydrogel from the human skin, showing strong adhesion and high elasticity. Scale bar, 1 cm.