Structured 3D Printed Dry ECG Electrodes Using Copper Based Filament

Commercial wet Silver and Chloride electrodes are used to monitor electrocardiogram (ECG) signals in numerous bioimpedance applications. These frequently single-use components that adhere the skin through an adhesive surface. This sticky surface is infamous for generating irritations during replacement removal of electrodes, making process uncomfortable patient. Because this type inappropriate many measuring situations, applicability dry investigated. study introduces use a copper-based filament (Electrifi) with highest reported conductivity (0.006 Ω.cm) biomedical applications, showcasing parameters 3D printed, semi-flexible wearable ECG signals. The effect printing-process (bed nozzle temperatures, infill pattern) on electrical performance thoroughly investigated (10 >100 electrode samples) find lowest impedance printed electrodes. influence ten resistivity samples three different structures (namely concentric, rough, flat as shown Fig. 1a) thicknesses have been experimented. analyzed play significant role electrodes’ values. Choosing proper setup these can enhance bio-impedance measurements similar ranges even below. flow was divided into two main stages. First, 15 mm diameter 2 thickness were structures, each six temperature settings, including temperatures (140 150 °C) bed (40, 60, 80 °C). At point, non-optimized recognized. Second, another optimization strategy presented, which involves experimenting 0.5 (concentric flat), one (80 A 2D profilometry provided, printing electrodes' roughness. Keithley Agilent semiconductor device analyzers record measurements; both acquire complex spectra per second frequency range from 20 kHz 400 kHz. excitation current set µA. investigates behavior stacked For purpose, binder clips securely hold resulting uniform force distribution. resistance performed using same equipment under fixed at then converted given cross-sectional area be 177 (or mm), respectively. significantly affect specifically (T ). roughness structured surfaces rough) observed increasing increase temperature. However, remained unchanged all parameters. thick decreased over frequency, showing capacitive (Fig. 1b). due air gap created between parasitic factors devices themselves, external such light, airflow, movement influenced measurement. depicted 1c, unlike rough electrode, uses additional ironing parameters, concentric equivalent Thus, T = °C 140 showed best among samples. Decreasing optimum generated better stable results higher sensitivity lower measurements. In conclusion, confirms functionality, conductivity, Defining material fundamental obtain reliable With new insight Electrifi filament, strategies studied single-process fused fabrication (FFF) create functional sensitive Figure 1. A) Images surfaces: (left), (middle), (right). B) Impedance measurement structure frequencies. C) Conductivity surfaces. 1