Fully 3D-Printed Dry EEG Electrodes

Abstract

Electroencephalography (EEG) is used to detect brain activity by recording electrical signals across various points on the scalp. Recent technological advancement has allowed brain signals to be monitored continuously through the long-term usage of EEG wearables. However, current EEG electrodes are not able to cater to different anatomical features, lifestyles, and personal preferences, suggesting the need for customisable electrodes. Despite previous efforts to create customisable EEG electrodes through 3D printing, additional processing after printing is often needed to achieve the required electrical properties. Although fabricating EEG electrodes entirely through 3D printing with a conductive material would eliminate the need for further processing, fully 3D-printed EEG electrodes have not been seen in previous studies. In this study, we investigate the feasibility of using a low-cost setup and a conductive filament, Multi3D Electrifi, to 3D print EEG electrodes. Our results show that the contact impedance between the printed electrodes and an artificial phantom scalp is under 550 Ω, with phase change of smaller than −30∘, for all design configurations for frequencies ranging from 20 Hz to 10 kHz. In addition, the difference in contact impedance between electrodes with different numbers of pins is under 200 Ω for all test frequencies. Through a preliminary functional test that monitored the alpha signals (7–13 Hz) of a participant in eye-open and eye-closed states, we show that alpha activity can be identified using the printed electrodes. This work demonstrates that fully 3D-printed electrodes have the capability of acquiring relatively high-quality EEG signals.

Sustainable development of electroencephalography materials and technology

“…100 In addition, a full 3DP method has been developed to manufacture EEG electrodes entirely through 3D printing using a conductive filament. 101 Over the last few decades, advances in 3DP techniques have facilitated the fabrication of accurate biological components and complicated 3D geometrics. 102 As a wellknown sustainable manufacturing process owing to its reduced waste, reduced usage, recycling and repurposing of materials, and customization potential, 3DP is promising for the industrial revolution in the production of various EEG electrodes with the outstanding advantages of hair compatibility, biocompatibility, comfort, and personalized capabilities.…”

Roadmap on printable electronic materials for next-generation sensors

“…There are many degrees of freedom in the design of such a fingered electrode, from the number of fingers, to the thickness of the fingers, to the tip profiles, and there is an ongoing challenge to devise suitable design rules for picking the best shapes in any given situation, potentially driven by a 3D scan of the area the electrode is to attach to. A future challenge is to enable alternative printed materials to silver/silver chloride, with some directly conductive printed electrodes now starting to emerge [618,619]. As no coating process is required these can potentially be both faster and cheaper to manufacture.…”

Hook Fabric Electroencephalography Electrode for Brain Activity Measurement without Shaving the Head

“…Skin-contact dry EEG electrodes were a introduced [18][19][20][21]. Flat skin-contact dry electrodes cannot be used in the hairy regio Although needle-based dry electrodes, such as a 3D-print legged electrode reported Tong et al [22], can be used on the hairy region, they are still heavy in weight and stiff structure. Mascia et al have developed a dry tattoo EEG electrode [23]; such electrod are highly affected by sweating and skin temperature, causing nonevent sensing, and d cay shortly with age.…”