Ag:TiN‐Coated Polyurethane for Dry Biopotential Electrodes: From Polymer Plasma Interface Activation to the First EEG Measurements

Pedrosa, Paulo; Fiedler, Patrique; Lopes, C.; Alves, E.; Haueisen, Jens; Machado, A. V.; Fonseca, C.; Vaz, F.

doi:10.1002/ppap.201500063

Cited by 28 publications

(36 citation statements)

References 61 publications

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“…The measured electrode-skin impedances with average values below 150 kX for 94 % of the channels in combination with the stable open circuit potential known to be attributed to silver and silver/silver-chloride electrodes (Fiedler et al 2014;Pedrosa et al 2015b) render the electrodes compatible with commercial amplifiers without the need for active pre-amplification or impedance converters. The impedance differences between hairless (frontal) and hairy (temporal and occipital) positions are negligible.…”

Section: Discussionmentioning

confidence: 99%

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Novel Multipin Electrode Cap System for Dry Electroencephalography

et al. 2015

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Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.

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Section: Discussionmentioning

confidence: 99%

“…Ag/AgCl is the gold standard material for wet electrodes and has outstanding electrochemical characteristics (Searle and Kirkup 2000;Fiedler et al 2014;Pedrosa et al 2015b). Thus, it has been selected for the electrically conductive coating of the multipin electrodes.…”

Section: Dry Electrodesmentioning

confidence: 99%

Novel Multipin Electrode Cap System for Dry Electroencephalography

et al. 2015

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“…For the depositions, two different types of substrates were used including Si (Boron doped, p type, <100> orientation, 525 µm thick) for chemical and (micro)structural characterization purposes and SiO 2 (fused silica) for optical spectra measurements. Before the depositions and in order to clean and activate the surface of the substrates, plasma treatments were performed by a Low-Pressure Plasma Cleaner by Diener Electronic equipped with a 40 kHz RF generator (Zepto Model, Ebhausen, Germany) [42], applying a power of 100 W. The substrates were first cleaned with O 2 plasma (80 Pa, for 5 min), and then activated with Ar plasma (80 Pa, for 15 min).…”

Section: Methodsmentioning

confidence: 99%

“…The heating ramp used was 5 • C/min and the isothermal period was 5 h, which cooled down freely inside the furnace, before reaching room temperature. Germany) [42], applying a power of 100 W. The substrates were first cleaned with O2 plasma (80 Pa, for 5 min), and then activated with Ar plasma (80 Pa, for 15 min). The films were deposited by reactive (DC) magnetron sputtering during 60 s in order to produce films with thicknesses around ~50 nm.…”

Section: Methodsmentioning

confidence: 99%

Gas Sensing with Nanoplasmonic Thin Films Composed of Nanoparticles (Au, Ag) Dispersed in a CuO Matrix

et al. 2019

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Magnetron sputtered nanocomposite thin films composed of monometallic Au and Ag, and bimetallic Au-Ag nanoparticles, dispersed in a CuO matrix, were prepared, characterized, and tested, which aimed to find suitable nano-plasmonic platforms capable of detecting the presence of gas molecules. The Localized Surface Plasmon Resonance phenomenon, LSPR, induced by the morphological changes of the nanoparticles (size, shape, and distribution), and promoted by the thermal annealing of the films, was used to tailor the sensitivity to the gas molecules. Results showed that the monometallic films, Au:CuO and Ag:CuO, present LSPR bands at ~719 and ~393 nm, respectively, while the bimetallic Au-Ag:CuO film has two LSPR bands, which suggests the presence of two noble metal phases. Through transmittance-LSPR measurements, the bimetallic films revealed to have the highest sensitivity to the refractive index changes, as well as high signal-to-noise ratios, respond consistently to the presence of a test gas.

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“…Traditionally, wet Ag/AgCl electrodes are considered the gold standard for biopotential measurements. These electrodes are non-polarizable, show a low and almost frequency independent electrode-skin interface impedance, in the order of a few tens of kΩ [9,10]. Nevertheless, these electrodes need an electrolyte gel to ensure a reliable electrode-skin connection in combination with an adhesive patch to fix the electrode position, thereby limiting gel spreading.…”

Section: Introductionmentioning

confidence: 99%

Dry Electrodes for Surface Electromyography Based on Architectured Titanium Thin Films

et al. 2020

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Electrodes of silver/silver chloride (Ag/AgCl) are dominant in clinical settings for surface electromyography (sEMG) recordings. These electrodes need a conductive electrolyte gel to ensure proper performance, which dries during long-term measurements inhibiting the immediate electrode’s reuse and is often linked to skin irritation episodes. To overcome these drawbacks, a new type of dry electrodes based on architectured titanium (Ti) thin films were proposed in this work. The architectured microstructures were zigzags, obtained with different sputtering incidence angles (α), which have been shown to directly influence the films’ porosity and electrical conductivity. The electrodes were prepared using thermoplastic polyurethane (TPU) and stainless-steel (SS) substrates, and their performance was tested in male volunteers (athletes) by recording electromyography (EMG) signals, preceded by electrode-skin impedance measurements. In general, the results showed that both SS and TPU dry electrodes can be used for sEMG recordings. While SS electrodes almost match the signal quality parameters of reference electrodes of Ag/AgCl, the performance of electrodes based on TPU functionalized with a Ti thin film still requires further improvements. Noteworthy was the clear increase of the signal to noise ratios when the thin films’ microstructure evolved from normal growth towards zigzag microstructures, meaning that further tailoring of the thin film microstructure is a possible route to achieve optimized performances. Finally, the developed dry electrodes are reusable and allow for multiple EMG recordings without being replaced.

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Ag:TiN‐Coated Polyurethane for Dry Biopotential Electrodes: From Polymer Plasma Interface Activation to the First EEG Measurements

Cited by 28 publications

References 61 publications

Novel Multipin Electrode Cap System for Dry Electroencephalography

Novel Multipin Electrode Cap System for Dry Electroencephalography

Gas Sensing with Nanoplasmonic Thin Films Composed of Nanoparticles (Au, Ag) Dispersed in a CuO Matrix

Dry Electrodes for Surface Electromyography Based on Architectured Titanium Thin Films

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