Micro-spike EEG electrode and the vacuum-casting technology for mass production

Ionic Liquid Gel‐Assisted Electrodes for Long‐Term Cutaneous Recordings

“…[ 10 ] Several studies report the fabrication of microstructures on the surface of the electrodes in order to increase the surface area and decrease the electrode impedance. [11][12][13][14] We recently reported the use of conducting polymers as dry electrodes with enhanced performance. [ 15 ] Another solution involves the use of spring-loaded contacts embedded in a fl exible substrate.…”

TO WHAT EXTENT CAN DRY AND WATER-BASED EEG ELECTRODES REPLACE CONDUCTIVE GEL ONES? - A Steady State Visual Evoked Potential Brain-computer Interface Case Study

“…The approaches range from developing hydrogel-based electrode (Alba et al, 2010) to numerous versions of dry electrodes. Dry electrode solutions include electrodes that are integrated into the wearable material (contactless electrodes) or affixed on top of the scalp (insulated electrodes) (Alizadeh- Taheri et al, 1996;Harland et al, 2002;von Ellenreider et al, 2006;Sullivan et al, 2007;Fonseca et al, 2007;Chi et al, 2009), electrodes that penetrate the outer layer of the skin (Ruffini et al, 2006;Ruffini et al, 2008;Griss et al, 2002;Gramatica et al, 2006;Chiou et al, 2006;Matteucci et al, 2007;Lin et al, 2008;Chang and Chiou, 2009;Ng et al, 2009;Dias et al, 2010), and dry contact electrodes that exhibit galvanic contact to the skin without the usage of additional electrolyte (Taheri et al, 1994;Matthews et al, 2007;Gargiulo et al, 2010). Due to skin damage they can cause, users might be exposed to a higher risk of infection and skin irritation (Ferree et al, 2001) for all dry electrode types except the last one -dry contact electrodes.…”

Experimental investigation on surface wettability of copper-based dry bioelectrodes

“…Thus, a dry bioelectrode can be used in the long-term recording process without conductive gel and skin preparation, which also has several obvious advantages such as lower impedance variations, smaller electrochemical noise, better stability, and convenient use. Several fabrication methods for bioelectrodes, micromachining such as wet etching processing [9][10][11][12], reactive ion etching [13,14] method [15], and 3D printing [16] have been developed to measure the physiological signal.…”

“…Later, Griss et al [13,14] developed the deep reactive ion etching method to fabricate spike electrodes using silicon that was subsequently covered with a Ag/AgCl double layer to reduce electrode interface noise. Ng et al [15] developed the vacuum casting method to fabricate microspike dry EEG electrodes, characterized the sensing performance in terms of the impedance level and stability, and showed a much higher efficiency in EEG measurements. Salvo et al [16] develop the 3D printing technology to fabricate electrodes with 180 conical needles.…”