Fig. 1: Wearable LFA for long-term, time-dynamic monitoring of cortisol in sweat induced with an integrated iontophoretic stimulation module.

a, Exploded schematic of the device, comprising an encapsulation cover, an iontophoretic stimulation module, hydrogels containing carbachol (blue) and KCl (yellow), and the skin-interfaced LFA. b, 3D representation of the device with an iontophoretic stimulation module and encapsulation layer. c, Magnified schematic of simultaneous sweat stimulation, collection onto cellulose paper and transport to an LFA strip via a sample pad. d, Detailed schematic of the LFA on a PET substrate. e, Exploded schematic of the LFA with a superhydrophilic and superhydrophobic viewing window, a sample pad, a conjugation pad, absorbent pads, nitrocellulose membranes and a PET substrate with skin adhesive. f, Photograph of an LFA with patterned hydrogels placed on the skin for iontophoretic stimulation. g, Photograph of the wearable LFA with the iontophoretic stimulation module and an encapsulation layer. h, Photograph of the device in operation for sensing cortisol concentrations in sweat. i, A series of optical images demonstrating a time-sequenced series of iontophoretic stimulation events. NC, nitrocellulose.