Epidermal electrode / neural tattoo

Epidermal electronics are ultrathin, skin-conformal sensor films — often only a few micrometres thick — that laminate onto skin and adhere by van der Waals forces alone, with an effective stiffness low enough to move with the skin and be nearly imperceptible to the wearer. Used as dry electrodes, they record electroencephalography, electromyography, and electrocardiography without conductive gel, and can be printed or transferred onto the scalp or face as a nearly invisible neural tattoo.

Their advantage over conventional wet electrodes is gel-free, low-motion-artifact, long-wear operation suited to ambulatory and consumer settings; their limits are signal quality relative to well-prepared clinical electrodes, sensitivity to sweat, hair, and skin shedding, and adhesion over days. They are a defining technology for wearable and out-of-the-lab BCI rather than for invasive recording.