Inkjet and Extrusion Printed Silver Biomedical Tattoo Electrodes

Ag/AgCl medical electrodes have served as the gold standard component for the acquisition of bioelectric signals in the human body (i.e. heart, muscle, and brain activity). Although ubiquitous, these electrodes exhibit an inability to sufficiently conform to the body and degrade in performance over time. As an alternative to conventional electrode fabrication methods, additive manufacturing methods such as inkjet and extrusion printing, can improve the efficiency of the fabrication process of electrical devices. These methods can also improve the performance of electrophysiological electrodes. To this end, tattoo-based electrodes were fabricated using inkjet and extrusion printing. These methods were optimized to print silver-based inks on tattoo paper, a porous substrate. The resulting electrodes were characterized in terms of sheet resistance and impedance as well as mechanical performance in terms of bending strain. The results for inkjet and extrusion printed tattoo electrodes are compared.