A 3D printed dry electrode for ECG/EEG recording

In this paper, the design, fabrication and testing of a 3D printed dry electrode is proposed. 3D printing represents an authentic breakthrough for the development and mass production of dry medical electrodes. In fact, it allows a fast and low cost production of high precision tridimensional shapes. This technique is reliable and efficient, and facilitates controllability over the whole process. Initially, 3D capable design software is used to draw the electrode model. The resulting file is simply loaded in a 3D printer whose resolution is 42 μm on x- and y-axes, and 16 μm on z-axis. The electrode is made by an insulating acrylic-based photopolymer. It consists of 180 conical needles (distance = 250 μm) on a truncated conical base. The metallization process undergoes two steps: sputtering of titanium as adhesion promotion layer and evaporation of gold to lower the impedance and prevent oxidation of the electrode. After electrode characterization, experimental results are presented and compared with planar wet Ag/AgCl electrodes for recording ECG–EEG.

► 3D printed dry electrodes are functional for both ECG and EEG recordings.
► 3D printed dry electrodes do not require skin preparation nor gel application.
► 3D printed dry electrodes are suitable for mass production.
► No skin penetration is needed for a correct bio-signal recording.
► No micro-machinery or silicon processes are needed.