Microneedle array electrode for human EEG recording

Abstract

Microneedle array electrodes for EEG significantly reduce the mounting time, particularly by circumvention of the need for skin preparation by scrubbing. We designed a new replication process for numerous types of microneedle arrays. Here, polymer microneedle array electrodes with 64 microneedles, in a nested 4×4 array, positioned on a circular disk of 10 mm diameter were fabricated and characterized. Needles have a length of 320 μm with a diameter of 100 μm. The DC-resistance of Ag-coated microneedle array electrodes on the skin is of the order of 150 kΩ. Using electrolyte gel this value decreases at least by a factor of 10. The pilot measurements on a healthy volunteer show excellent signal-to-noise ratios. According to conventional electrodes also Ag/AgCl instead of Ag only was used to coat the microneedle array. Both coatings, either with or without gel, certified for EEG recordings