Ultraconformable Temporary Tattoo Electrodes for Electrophysiology

TLDR

Skin‑contact electrophysiology requires electrical interface with skin, yet stiff pregelled or dry electrodes cause discomfort and limit mobility. This work introduces dry, invisible temporary tattoo electrodes for skin‑contact electrophysiology. The electrodes are inkjet‑printed conductive‑polymer arrays on decal paper, transferred to skin, and their impedance was measured over 1‑h and 48‑h periods versus standard electrodes. The ultrathin (<1 µm) tattoo electrodes adhere conformally, enabling reliable EMG and ECG recordings on limbs and face, support hair growth for long‑term use, and are scalable for low‑cost production.

Abstract

Abstract Electrically interfacing the skin for monitoring personal health condition is the basis of skin‐contact electrophysiology. In the clinical practice the use of stiff and bulky pregelled or dry electrodes, in contrast to the soft body tissues, imposes severe restrictions to user comfort and mobility while limiting clinical applications. Here, in this work dry, unperceivable temporary tattoo electrodes are presented. Customized single or multielectrode arrays are readily fabricated by inkjet printing of conducting polymer onto commercial decal transfer paper, which allows for easy transfer on the user's skin. Conformal adhesion to the skin is provided thanks to their ultralow thickness (&lt;1 µm). Tattoo electrode–skin contact impedance is characterized on short‐ (1 h) and long‐term (48 h) and compared with standard pregelled and dry electrodes. The viability in electrophysiology is validated by surface electromyography and electrocardiography recordings on various locations on limbs and face. A novel concept of tattoo as perforable skin‐contact electrode, through which hairs can grow, is demonstrated, thus permitting to envision very long‐term recordings on areas with high hair density. The proposed materials and patterning strategy make this technology amenable for large‐scale production of low‐cost sensing devices.