Soft Dry Electrodes for Electrocardiogram with Conductive Silver Nanowires

2014 ◽  
Vol 1685 ◽  
Author(s):  
Amanda Myers ◽  
Yong Zhu
Keyword(s):  
Health Monitoring ◽  
Silver Chloride ◽  
Silver Nanowires ◽  
Skin Irritation ◽  
Hospital Setting ◽  
Skin Impedance ◽  
Ecg Signals ◽  
Dry Electrode ◽  
Silver Silver

ABSTRACTWith increasing attention towards long-term health monitoring, there is a pressing need to create noninvasive sensors that monitor vital bioelectronic signals. Particular importance is placed on measuring electrocardiogram (ECG) signals as heart issues are widespread and can be prevented with the proper warning and care of potential problems. Currently, ECGs are taken in a hospital setting using disposable silver-silver chloride (Ag/AgCl) pre-gelled electrodes. Unfortunately, this cannot translate to a long-term monitoring setting due to the electrolytic gel of the electrodes drying and causing skin irritation. This paper presents a soft, skin-mountable dry electrode based on silver nanowires (AgNWs) for measuring ECG signals that can be used in long-term, wearable health monitoring due to the elimination of the electrolytic gel. The AgNWs are embedded in polydimethylsiloxane (PDMS), which creates a robust design that will not suffer from delamination or cracking problems that can eventually lead to loss of conductivity. The electrode is characterized by electrode-skin impedance as a function of frequency and by the surface resistance as the electrode is stretched. The performance of the dry electrode is evaluated and comparable to that of conventional Ag/AgCl electrodes. The ability of the dry electrode to conform to skin is believed to compensate for the lack of an electrolytic gel.

scholarly journals A Novel Highly Durable Carbon/Silver/Silver Chloride Composite Electrode for High-Definition Transcranial Direct Current Stimulation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1962
Author(s):  
Lingjun Li ◽  
Guangli Li ◽  
Yuliang Cao ◽  
Yvonne Yanwen Duan
Keyword(s):  
Service Life ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Silver Chloride ◽  
Cycling Performance ◽  
High Definition ◽  
Silver Silver ◽  
Sintered Ag ◽  
Silver Silver Chloride

High-definition transcranial direct current stimulation (HD-tDCS) is a promising non-invasive neuromodulation technique, which has been widely used in the clinical intervention and treatment of neurological or psychiatric disorders. Sintered Ag/AgCl electrode has become a preferred candidate for HD-tDCS, but its service life is very short, especially for long-term anodal stimulation. To address this issue, a novel highly durable conductive carbon/silver/silver chloride composite (C/Ag/AgCl) electrode was fabricated by a facile cold rolling method. The important parameters were systematically optimized, including the conductive enhancer, the particle size of Ag powder, the C:Ag:PTFE ratio, the saline concentration, and the active substance loading. The CNT/Ag/AgCl-721 electrode demonstrated excellent specific capacity and cycling performance. Both constant current anodal polarization and simulated tDCS measurement demonstrated that the service life of the CNT/Ag/AgCl-721 electrodes was 15-16 times of that of sintered Ag/AgCl electrodes. The much longer service life can be attributed to the formation of the three-dimensional interpenetrating conductive network with CNT doping, which can maintain a good conductivity and cycling performance even if excessive non-conductive AgCl is accumulated on the surface during long-term anodal stimulation. Considering their low cost, long service life, and good skin tolerance, the proposed CNT/Ag/AgCl electrodes have shown promising application prospects in HD-tDCS, especially for daily life scenarios.

scholarly journals Dry Electrodes for Surface Electromyography Based on Architectured Titanium Thin Films

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2135 ◽  
Author(s):  
Marco S. Rodrigues ◽  
Patrique Fiedler ◽  
Nora Küchler ◽  
Rui P. Domingues ◽  
Cláudia Lopes ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Electromyography ◽  
Silver Chloride ◽  
Thermoplastic Polyurethane ◽  
Skin Irritation ◽  
Normal Growth ◽  
Quality Parameters ◽  
Skin Impedance ◽  
Dry Electrodes

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.

A comfortability and signal quality study of conductive weave electrodes in long-term collection of human electrocardiographs

2018 ◽  
Vol 89 (11) ◽  
pp. 2098-2112 ◽  
Author(s):  
Xueliang Xiao ◽  
Ke Dong ◽  
Chenhao Li ◽  
Guanzheng Wu ◽  
Hongtao Zhou ◽  
...  
Keyword(s):  
Skin Irritation ◽  
Woven Fabrics ◽  
Comfort Level ◽  
Signal Quality ◽  
High Quality ◽  
Contact Impedance ◽  
Ecg Signals ◽  
Skin Contact ◽  
Textile Electrodes

Long-term electrocardiogram (ECG) recording can reveal some vital cardiovascular disorders and provide warning of human sudden cerebral or vascular diseases in advance. This requires high-quality ECG skin electrodes. Gel (Ag/AgCl) electrodes were reported to have good signal quality in ECG acquisition, but easily caused human skin irritation or allergy. Consequently, textile electrodes have attracted more attention for long-term ECG acquisition. In this paper, eight woven fabrics with diverse yarns and weft densities were fabricated in plain and honeycomb structures. The fabrics were investigated in terms of comfortability, fabric–skin contact impedance and acquired bio-signal quality. Honeycomb weave electrodes were measured with a high comfort level from subjective and objective views, including pleasant tactile comfort, high visual acceptance, good air permeability and good heat transfer. Weave electrodes made of all conductive filaments in high density had low skin contact impedance and high-quality ECG signals. An increase of compression load on weave electrodes resulted in a decrease of contact impedance with a high signal quality. A conductive honeycomb weave with unit repeat of 6*6 warps*wefts presented the highest score of acquired ECG signals of all studied electrodes based on the qualities of the QRS complex, P and T waves, R peak amplitude and variation and signal-to-noise ratio. This study contributes to the future design and fabrication of textile electrodes using honeycomb weave in long-term and real-time collection of human ECGs.

scholarly journals Influence of silver/silver chloride electroless plating on the Shore hardness of polyurethane substrates for dry EEG electrodes

2021 ◽  
Vol 7 (2) ◽  
pp. 9-12
Author(s):  
Indhika Fauzhan Warsito ◽  
René Machts ◽  
Stefan Griebel ◽  
Patrique Fiedler ◽  
Jens Haueisen
Keyword(s):  
Electroless Plating ◽  
Silver Chloride ◽  
Shore Hardness ◽  
Absolute Increase ◽  
3D Print ◽  
Hardness Tester ◽  
Hardness Increase ◽  
Silver Silver ◽  
Silver Silver Chloride

Abstract Dry electrodes enable a shorter preparation time for infant EEG. Since infant skin is more sensitive than adult skin, soft electrodes are required to reduce the mechanical stress for this sensitive skin. Thus, soft electrodes are crucial for eventual repetitive and long-term use like in neonatal intensive care units. A biocompatible polyurethane (PU) can be produced in low hardness resulting in a soft and flexible electrode substrate. Silver/silver chloride (Ag/AgCl) electroless plating provides a conductive, electrochemically stable coating but the process may alter the mechanical properties of the electrode substrate. In this study, we assess the hardness of PU material before and after Ag/AgCl plating. The test sample design for Shore hardness measurement is based on ISO 7619-1:2010. Sample production consists of a 3D print master model, silicone molding, PU casting, and finally electroless plating. UPX 8400-1 (Sika AG, Switzerland) is used for the sample substrates. Test samples are produced with 7 different Shore hardness (range A40-A95) and 14 samples (each hardness: 1 uncoated and 1 coated). The hardness measurements are carried out with a lever-operated test stand Shore hardness tester model with a digital hardness tester (TI-AC with HDA 100-1, KERN &SOHN GmbH, Germany).. It is shown that there is a hardness increase (Shore A) due to Ag/AgCl coating with a grand average of 1.1±0.7 (p<0.05). The largest increase of 2.1±0.2 is seen on the initial lowest Shore hardness sample (Shore hardness: 43.4±0.1). The absolute increase of hardness due to the Ag/AgCl coating decreases with increasing substrate hardness. It is concluded that there is no strong hardness increase of PU substrates due to Ag/AgCl plating. Therefore, the material is suitable as a soft electrode for repetitive and long-term use in infant applications.

scholarly journals A Long-Term, Portable ECG Patch Monitor Based on Flexible Dry Electrode

2022 ◽  
Author(s):  
Hao Chu ◽  
Chenxi Yang ◽  
Yantao Xing ◽  
Jianqing Li ◽  
Chengyu Liu
Keyword(s):  
Electrode Impedance ◽  
Ecg Monitoring ◽  
High Quality ◽  
Ecg Signals ◽  
Skin Electrode ◽  
Rr Interval ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
And Storage

Abstract PurposeLong-term electrocardiogram (ECG) monitoring is an essential approach for the early diagnosis of cardiovascular diseases. Flexible dry electrodes that contains electrolyte without water could be a potential substitution of wet electrodes for long-term ECG monitoring. Therefore, this paper developes a long-term, portable ECG patch based on flexible dry electrodes, namely SEUECG-100.MethodA device consists of analog-front-end acquisition, data acquisition, and storage modules is developed and tested. An impedance test was conducted to compare the skin-electrode impedance of the flexible dry electrode and the Ag/AgCl wet electrode. The ECG signals were simutanously collected from the same subject using the SEUECG-100 and Shimmer device , which were then compared and analyzed from the perspective of ECG morphology, RR interval, and signal quality indices (SQI).ResultsThe experimental results reveal that the flexible dry electrode has the characteristics of low skin-electrode impedance. SEUECG-100 could collect high-quality ECG signals. The ECG signals collected by the two devices have a high RR interval correlation (r=0.999). SQI results show that SEUECG-100 is better than the Shimmer device in overcoming baseline drift. Long-term ECG acquisition and storage experiments show that SEUECG-100 could collect ECG signals with good stability and high reliability.ConclusionThe implementation of the proposed system design with dry electrodes could can effectively record long-term ECG monitoring with high quality in comparison to systems with wet electrodes from both impedance characteristics and signal morphology aspects.

Silver-silver chloride electrode as a nonpolarizable bioelectrode

1963 ◽  
Vol 18 (2) ◽  
pp. 397-401 ◽  
Author(s):  
Walter Feder
Keyword(s):  
Concentration Polarization ◽  
Silver Chloride ◽  
Stable State ◽  
Routine Laboratory ◽  
Silver Chloride Electrode ◽  
Polarization Effects ◽  
Laboratory Conditions ◽  
Silver Silver ◽  
Silver Silver Chloride

A thermal-electrolytic method for the preparation of Ag AgCl electrodes suitable for measurement of bioelectrical changes in the microvolt range is given in detail. A potential of 0.5 mv or less between electrode pairs is easily attained; and such electrodes will accurately measure emf generated by both steady and fluctuating phenomena down to ±5 μv under routine laboratory conditions. Studies in the variations in potential for pairs of electrodes from the time they are introduced into the circuit until they reach a stable state, as well as long-term drift are presented. These data are analyzed in terms of activation, ohmic, and concentration polarization effects. Submitted on July 19, 1962

scholarly journals Development of Washable Silver Printed Textile Electrodes for Long-Term ECG Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6233
Author(s):  
Abreha Bayrau Nigusse ◽  
Benny Malengier ◽  
Desalegn Alemu Mengistie ◽  
Granch Berhe Tseghai ◽  
Lieva Van Langenhove
Keyword(s):  
Silver Chloride ◽  
Signal To Noise Ratio ◽  
Polyester Fabric ◽  
Signal Quality ◽  
Ecg Monitoring ◽  
Textile Electrodes ◽  
Elastic Strap ◽  
Silver Silver ◽  
Silver Silver Chloride

Long-term electrocardiography (ECG) monitoring is very essential for the early detection and treatment of cardiovascular disorders. However, commercially used silver/silver chloride (Ag/AgCl) electrodes have drawbacks, and these become more obvious during long-term signal monitoring, making them inconvenient for this use. In this study, we developed silver printed textile electrodes from knitted cotton and polyester fabric for ECG monitoring. The surface resistance of printed electrodes was 1.64 Ω/sq for cotton and 1.78 Ω/sq for polyester electrodes. The ECG detection performance of the electrodes was studied by placing three electrodes around the wrist where the electrodes were embedded on an elastic strap with Velcro. The ECG signals collected using textile electrodes had a comparable waveform to those acquired using standard Ag/AgCl electrodes with a signal to noise ratio (SNR) of 33.10, 30.17, and 33.52 dB for signals collected from cotton, polyester, and Ag/AgCl electrodes, respectively. The signal quality increased as the tightness of the elastic strap increased. Signals acquired at 15 mmHg pressure level with the textile electrodes provided a similar quality to those acquired using standard electrodes. Interestingly, the textile electrodes gave acceptable signal quality even after ten washing cycles.

scholarly journals Comparison of three types of dry electrodes for electroencephalography

ACTA IMEKO ◽  
2014 ◽  
Vol 3 (3) ◽  
pp. 33 ◽  
Author(s):  
Patrique Fiedler ◽  
Jens Haueisen ◽  
Dunja Jannek ◽  
Stefan Griebel ◽  
Lena Zentner ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Silver Chloride ◽  
Measurement Range ◽  
Open Circuit ◽  
Signal Acquisition ◽  
The Novel ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
Silver Silver ◽  
Silver Silver Chloride

A potential new area of routine application for electroencephalography (EEG) is the brain-computer interface, which might enable disabled people to interact with their environment, based on measured brain signals. However, conventional electroencephalography is not suitable here due to limitations arising from complicated, time-consuming and error-prone preparation. Recently, several approaches for dry electrodes have been proposed. Our aim is the comparison and assessment of three types of dry electrodes and standard wet silver/silver-chloride electrodes for EEG signal acquisition. We developed novel EEG electrodes with titanium and polyurethane as base materials, which were coated with nanometer sized titanium-nitride films. Furthermore gold multi-pin electrodes were arranged on printed circuit boards. The results of the comparison of these electrodes with conventional wet silver/silver-chloride electrodes in terms of electrode impedances are presented, as well as open circuit potentials and biosignal measurements. Impedances were significantly higher for all dry electrode types compared to wet electrodes, but still within the measurement range of today’s standard biosignal amplifiers. It was found that the novel dry titanium and polyurethane based electrodes show biosignal quality equivalent to conventional electrodes. In conclusion, the novel dry electrodes seem to be suitable for application in brain-machine interfaces.

scholarly journals Miura-ori structured flexible microneedle array electrode for biosignal recording

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yue Hou ◽  
Zhaoyu Li ◽  
Ziyu Wang ◽  
Hongyu Yu
Keyword(s):  
Health Monitoring ◽  
Biceps Brachii ◽  
Metal Layer ◽  
Skin Impedance ◽  
Microneedle Array ◽  
Long Term Stability ◽  
Array Electrode ◽  
Device Reliability ◽  
Air Ventilation

AbstractHighly reliable signal recording with low electrode-skin impedance makes the microneedle array electrode (MAE) a promising candidate for biosignal sensing. However, when used in long-term health monitoring for some incidental diseases, flexible microneedles with perfectly skin-tight fit substrates lead to sweat accumulation inside, which will not only affect the signal output but also trigger some skin allergic reactions. In this paper, a flexible MAE on a Miura-ori structured substrate is proposed and fabricated with two-directional in-plane bendability. The results from the comparison tests show enhanced performance in terms of (1) the device reliability by resisting peeling off of the metal layer from the substrate during the operation and (2) air ventilation, achieved from the air-circulating channels, to remove sweat. Bio-signal recordings of electrocardiography (ECG), as well as electromyography (EMG) of the biceps brachii, in both static and dynamic states, are successfully demonstrated with superior accuracy and long-term stability, demonstrating the great potential in health monitoring applications.

Multifunctional Skin-Like Electronics for Long-Term Health Monitoring

2012 ◽  
Author(s):  
Woon-Hong Yeo ◽  
Yun-Soung Kim ◽  
Jongwoo Lee ◽  
John A. Rogers
Keyword(s):  
Health Monitoring ◽  
Skin Irritation ◽  
Electronic System ◽  
Metal Electrode ◽  
Skin Surface ◽  
Quality Data ◽  
Contact Impedance ◽  
Skin Preparation ◽  
Wireless Data Acquisition

Conductive gel-based wet electrodes along with the skin preparation have been widely used for the measurement of electrophysiological signals on the skin in a health monitoring system. The use of conductive gels is necessary to reduce the contact impedance between the skin surface and electrode. However, it can cause skin irritation or allergic reactions. This issue originates from the mismatch between the soft, curvy skin epidermis and the rigid, flat metal electrode. To address the issues of conventional electronics, we introduce a new class of ‘skin-like’ electronic system. The electronics can be conformally laminated on the epidermis, such that it ensures high-quality data recording without conductive gels. The skin-like electronics incorporates electrophysiological-, temperature-, and strain sensors in the system for multimodal functionality. To provide robust wearability for a week, a medical spray bandage is utilized to shield the sensor on the skin. The multifunctional sensor measures physiological signals and they are recorded with a commercial wireless data acquisition system along with a releasable, skin-like connector. This novel, multifunctional electronics on the skin can potentially replace the irritable and cumbersome wet electrodes for portable, long-term health monitoring at home.

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