Dry tDCS: Tolerability of a novel multilayer hydrogel composite non-adhesive electrode for transcranial direct current stimulation.

•Validated the performance of first “dry” electrodes for tDCS.•The Multilayer hydrogel composite (MHC) dry-electrode excludes saline or electrolyte, adhesive at the skin interface, or electrode preparation steps.•Performance of the MHC dry-electrode verified using skin-phantom (voltage and current mapping inside at the phantom surface and inside the electrode using a novel flexible printed circuit board current sensor matric (fPCB-CSM), and human trial including tolerability, skin erythema (redness), and electrode current mapping.•Experimental data were compared against FEM model.•Under tested conditions, the tolerability, and adverse-event profile of MHC dry-electrode performance were improved or comparable to the state-of-the-art sponge electrode.