Fabrication of an LM-based epidermal electrode and characterization of its electrical properties. (a) Schematic of the fabrication process. (b) PVP stabilized LM nanoparticles suspended in ethanol. (c) SEM image of LM before and after mechanical sintering. (d) Electrical conductivity before and after mechanical sintering. (e) Photograph of the ultrathin electrode. (f) Change in conductivity during two consecutive bending processes from 0° to 180°. (g) If compressed by human skin, the LM wire maintains good conductivity and skin compatibility. (h) Flexibility and adaptability of the LM electrode to the human skin.