Search

Background: Functional Electrical Stimulation (FES) represents a promising technique for promoting functional recovery in individuals with neuromuscular diseases. Traditionally, current pulses are delivered through self‐adhesive hydrogel Ag/AgCl electrodes, which allow a good contact with the skin, are easy‐to‐use and have a moderate cost. However, skin adherence decreases after a few uses and skin irritations can originate. Recently, textile electrodes have become an attractive alternative as they assure increased durability, easy integration into clothes and can be conveniently cleaned, improving the wearability of FES. However, as various manufacture processes were attempted, their clear validation is lacking. This proof‐of‐concept study proposes a novel set of ink‐based printed textile electrodes and compares them to adhesive hydrogel electrodes in terms of impedance, stimulation performance and perceived comfort. Methods: The skin–electrode impedance was evaluated for both types of electrodes under different conditions. These electrodes were then used to deliver FES to the Rectus Femoris of 14 healthy subjects to induce its contraction in both isometric and dynamic conditions. This allowed to compare the two types of electrodes in terms of sensory, motor, maximum and pain thresholds, FES‐induced range of motion during dynamic tests, FES‐induced torque during isometric tests and perceived stimulation comfort. Results: No statistically significant differences were found both in terms of stimulation performance (Wilcoxon test) and comfort (Generalized Linear Mixed Model). Conclusion: The results showed that the proposed ink‐based printed textile electrodes can be effectively used as alternative to hydrogel ones. Further experiments are needed to evaluate their durability and their response to sterilizability and stretching tests. [ABSTRACT FROM AUTHOR]

The development of highly conductive fibril‐type textile electrodes is crucial for the advancement of various smart wearable electronics including high‐performance energy storage devices. To achieve this goal, it is essential to convert insulating textiles into conductive counterparts while maintaining flexibility and porosity. Additionally, the incorporation of electrochemically active components into textile conductors enables tailor‐made textile energy electrodes for specific applications. Thus, textile conductors act not only as conductors but also as energy reservoirs for energy‐active components, providing a facile electron transfer network. However, textile conductors fabricated by most existing methods face challenges such as low conductivity, blockage, and brittleness. One approach to overcome these problems is to utilize interfacial interactions between individual components and textiles. Conductive nanoparticle assembly and electrodeposition based on such rational design result in highly conductive, flexible, and large surface area textile conductors. The subsequent guided assembly of active components creates high‐performance textile energy electrodes. This perspective describes how interfacial interaction‐based assembly can enhance the performance of textile conductors and textile energy electrodes. It also explores various conductor preparation approaches and recent advances in the field for applications in supercapacitors and lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

In this work, different textile electrodes are assessed and a novel measurement system for their characterization is presented. Those electrodes are made of a paraffin-coated conductive yarn embroidered into a textile substrate following two distinct embroidering techniques with up to six different geometry characteristics for each one. To evaluate the sensor behaviour, the impedance has been measured by means of an LCR meter at 50 kHz at atmospheric conditions (25 °C and about 40% relative humidity). The results obtained were as follows. First, the application of a paraffin wax coating to the conductive yarn enhances better test results and eases the production process. Second, the proposed measurement system provides much more consistent results in comparison with other standard techniques already in use. Finally, higher densities of conductive yarn obtained lower resistance values, and so impedance, rather than other configurations. [ABSTRACT FROM AUTHOR]

This report aims to provide a patent landscape analysis on carbon allotrope-based textile electrodes and biosensors to measure biosignals and detect several parameters. Espacenet, a free-of-charge patent database provided by the EPO (European Patent Office) and containing data on more than 140 million patent publications from over 100 countries, was used as the reference database. The patent search was carried out by combining keywords and classification symbols. Both classification schemes (IPC–International Patent Classification and CPC–Cooperative Patent Classification) were used. As a result of this study, a total of 227 patent documents were found between 2002 and 2023. The first patent application claiming a fabric electrode arrangement with carbon black as conductive material was filed in 2002 (and published in 2004) by Philips. 2021 was the year with the highest number of published patent applications, with 36 documents. The United States was ranked first with 126 patent documents. Carbon nanotubes and graphene are the most patented carbon allotrope materials, while body temperature, motion, and heart rate measurements are the main disclosed applications. We also analyzed the Orbit database obtaining 288 patent documents (vs. 227) with only 238 still active records (148 granted and 90 pending applications): the first application by Philips on an electrode arrangement is confirmed, and the patent distribution shows a peak in the period 2016–2020 (146 records available), while today it seems to be stable or even decreasing ("only" 52 records in the half period January 2021–June 2023). This outcome suggests that this material and related technology has reached its maximum exploitation or has not demonstrated a disruptive output. [ABSTRACT FROM AUTHOR]

Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0–10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity-dependent 2−3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a frequency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention. [ABSTRACT FROM AUTHOR]

There is an increasing interest in long-term electrocardiography (ECG) monitoring in veterinary clinical practice. ECG is the most essential physiological signal in diagnosing and managing heart diseases both in humans and animals. Electrodes are the main components that affect the quality of the acquired signal. This study focuses on the development of silver-coated textile electrodes for veterinary ECG testing (particularly for dogs). Silver printed polyester, embroidered, and silver-plated conductive hook textile electrodes were used for ECG measurement in dogs. This is an important validation for the use of textile ECG sensors in combination with hairy skin. ECG signals were collected while the animal was in a static position and walking on a smooth surface. The ECG signals collected from the dog using the silver printed polyester and embroidered textile electrodes with slight skin preparation have identifiable P, QRS, and T waveforms and were comparable with signals from standard silver/silver chloride (Ag/AgCl) electrodes. Results revealed that these textile electrodes can be used for ECG monitoring in a dog to avoid associated problems with commercially used crocodile clamps and standard Ag/AgCl electrodes. The hook electrodes show promising results when placed on the hairy regions of a dog without any skin preparation. [ABSTRACT FROM AUTHOR]

The development of highly conductive fibril‐type textile electrodes is crucial for the advancement of various smart wearable electronics including high‐performance energy storage devices. To achieve this goal, it is essential to convert insulating textiles into conductive counterparts while maintaining flexibility and porosity. Additionally, the incorporation of electrochemically active components into textile conductors enables tailor‐made textile energy electrodes for specific applications. Thus, textile conductors act not only as conductors but also as energy reservoirs for energy‐active components, providing a facile electron transfer network. However, textile conductors fabricated by most existing methods face challenges such as low conductivity, blockage, and brittleness. One approach to overcome these problems is to utilize interfacial interactions between individual components and textiles. Conductive nanoparticle assembly and electrodeposition based on such rational design result in highly conductive, flexible, and large surface area textile conductors. The subsequent guided assembly of active components creates high‐performance textile energy electrodes. This perspective describes how interfacial interaction‐based assembly can enhance the performance of textile conductors and textile energy electrodes. It also explores various conductor preparation approaches and recent advances in the field for applications in supercapacitors and lithium‐ion batteries.

The development of smart wearable solutions for monitoring daily life health status is increasingly popular, with chest straps and wristbands being predominant. This study introduces a novel sensorized T-shirt design with textile electrodes connected via a knitting technique to a Movesense device. We aimed to investigate the impact of stationary and movement actions on electrocardiography (ECG) and heart rate (HR) measurements using our sensorized T-shirt. Various activities of daily living (ADLs), including sitting, standing, walking, and mopping, were evaluated by comparing our T-shirt with a commercial chest strap. Our findings demonstrate measurement equivalence across ADLs, regardless of the sensing approach. By comparing ECG and HR measurements, we gained valuable insights into the influence of physical activity on sensorized T-shirt development for monitoring. Notably, the ECG signals exhibited remarkable similarity between our sensorized T-shirt and the chest strap, with closely aligned HR distributions during both stationary and movement actions. The average mean absolute percentage error was below 3%, affirming the agreement between the two solutions. These findings underscore the robustness and accuracy of our sensorized T-shirt in monitoring ECG and HR during diverse ADLs, emphasizing the significance of considering physical activity in cardiovascular monitoring research and the development of personal health applications. [ABSTRACT FROM AUTHOR]

Purpose: To compare fixed transverse textile electrodes (TTE) knitted into a sock versus motor point placed standard gel electrodes (MPE) on peak venous velocity (PVV) and discomfort, during calf neuromuscular electrical stimulation (calf-NMES). Methods: Ten healthy participants received calf-NMES with increasing intensity until plantar flexion (measurement level I = ML I), and an additional mean 4 mA intensity (ML II), utilizing TTE and MPE. PVV was measured with Doppler ultrasound in the popliteal and femoral veins at baseline, ML I and II. Discomfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05. Results: TTE and MPE both induced significant increases in PVV from baseline to ML I and significantly higher increases to ML II, in both the popliteal and femoral veins (all p < 0.001). The popliteal increases of PVV from baseline to both ML I and II were significantly higher with TTE versus MPE (p < 0.05). The femoral increases of PVV from baseline to both ML I and II were not significantly different between TTE and MPE. TTE versus MPE resulted at ML I in higher mA and NRS (p < 0.001), and at ML II in higher mA (p = 0.005) while NRS was not significantly different. Conclusion: TTE integrated in a sock produces intensity-dependent increases of popliteal and femoral hemodynamics comparable to MPE, but results in more discomfort at plantar flexion due to higher current required. TTE exhibits in the popliteal vein higher increases of PVV compared to MPE. Trial registration: Trial_ID: ISRCTN49260430. Date: 11/01/2022. Retrospectively registered. [ABSTRACT FROM AUTHOR]

Electrocardiogram (ECG) signals are often measured for medical purposes and in sports. While common Ag/AgCl glued gel electrodes enable good electrode skin contact, even during movements, they are not comfortable and can irritate the skin during long-term measurements. A possible alternative is textile electrodes, which have been investigated extensively during the last years. These electrodes, however, are usually not able to provide reliable, constant skin contact, resulting in reduced signal quality. Another important problem is the modification of the electrode surface due to washing or abrasion, which may impede the long-term use of such textile electrodes. Here, we report a study of washing and abrasion resistance of different ECG electrodes based on an isolating woven fabric with conductive embroidery and two conductive coatings, showing unexpectedly high abrasion resistance of the silver-coated yarn and optimum ECG signal quality for an additional coating with a conductive silicone rubber. Sheet resistances of the as-prepared electrodes were in the range of 20–30 Ω, which was increased to the range of 25–40 Ω after five washing cycles and up to approximately 50 Ω after Martindale abrasion tests. ECG measurements during different movements revealed reduced motion artifacts for the electrodes with conductive silicone rubber as compared to glued electrodes, suggesting that electronic filtering of such noise may even be easier for textile electrodes than for commercial electrodes. [ABSTRACT FROM AUTHOR]

In recent days, a digestive abnormality is common due to modern life-style and food habits followed. For every ten adults in the world, four suffer from functional gastrointestinal (GI) disorders of varying severity. Further, this is demonstrated by a study of more than 73,000 people across 33 countries. Also, the subjects who have undergone surgery/medication may feel healthy and they cannot feel or realize the internal health disorders, resulting in severe consequences. In this regard, an electrogastrogram (EGG) has gained more significance since it is non-invasive and involves an easy process for screening digestive abnormalities. EGGs are electrical signals, which have strong association with digestion. Also, the EGG can be recorded using non-invasive/surface electrodes. In this work, two different conductive textile materials, namely stainless-steel fibers and Copper–Nickel-plated nylon, are utilised to fabricate non-invasive electrodes. Further, the developed electrodes are placed on the abdomen over the stomach and the EGG signals are acquired from healthy individuals. Also, various time and frequency domain features are extracted from two different EGG signals acquired using developed electrodes with different materials and are analysed. Additionally, the XAI, namely Shapley Additive Explanation (SHAP), technique is utilised to analyse and test the efficacy of the developed textile-based electrodes and to select the best electrode for EGG signal acquisition. This work appears to be highly significant since the developed electrode selected using the XAI tool shall possess a wide scope in wearable applications.

There is an increasing interest in long-term electrocardiography (ECG) monitoring in veterinary clinical practice. ECG is the most essential physiological signal in diagnosing and managing heart diseases both in humans and animals. Electrodes are the main components that affect the quality of the acquired signal. This study focuses on the development of silver-coated textile electrodes for veterinary ECG testing (particularly for dogs). Silver printed polyester, embroidered, and silver-plated conductive hook textile electrodes were used for ECG measurement in dogs. This is an important validation for the use of textile ECG sensors in combination with hairy skin. ECG signals were collected while the animal was in a static position and walking on a smooth surface. The ECG signals collected from the dog using the silver printed polyester and embroidered textile electrodes with slight skin preparation have identifiable P, QRS, and T waveforms and were comparable with signals from standard silver/silver chloride (Ag/AgCl) electrodes. Results revealed that these textile electrodes can be used for ECG monitoring in a dog to avoid associated problems with commercially used crocodile clamps and standard Ag/AgCl electrodes. The hook electrodes show promising results when placed on the hairy regions of a dog without any skin preparation.

Electrostimulation is a way of treatment various nerve and muscle injuries as well as acute and chronic pain conditions. The electrotherapy which is increasingly used in physiotherapy, muscle is exposed to an electrical pulse in order to activate excitable tissue using external electrodes with the aim of building muscle strength, enhancement healing, improvement in patient's mobility or reducing painTextile based electrodes are significantly noticed in the aspects of being flexible and re-usable and no needs of hydrogels, thereby avoiding skin irritation and allergic reactions and enhancing user comfort. This article presents a kind of textile based electrodes made of conductive yarns containing stainless steel/plyester blend fiber. The embroidery technique was used to prepare the textile based electrodes. Samples were examined on 10 people with pain in their bodies in a hospital without being moisturised. The purpose of this study is to asses the performance of 3 different textile based electrodes, considering the conductivity of the yarns which have been used to produce textile based electrodes, the usfulness of them for electrotherapy and comparing them with rubber electrodes commonly are used in clinics regularly. [ABSTRACT FROM AUTHOR]

In this paper, we evaluated the impedance of textile electrodes for electroencephalography measurements. We compared the commercially available standard dry silver/silver chloride dry electrodes, copper-based, and silver-based textile electrodes by measuring impedance on the skin. First, on dry skin, the impedance range of the electrodes was 93–350 kΩ at 0 min; after 60 min, the range was 20–56 kΩ. The commercial electrode showed the lowest impedance of 20 kΩ, and the silver-based textile electrode showed the highest impedance of 56 kΩ in dry skin conditions after 60 min. When tap water was applied as an electrolyte, the impedance range was 13–15 kΩ at 0 min; after 60 min, the range was 17–22 kΩ for all three types of electrodes. In this case, the copper-based textile electrode showed the lowest impedance of 17 kΩ and the commercial electrode showed the highest impedance of 22 kΩ after 60 min. When saline water was applied as an electrolyte, at 0 min, the impedance range was 8–11 kΩ; after 60 min, the range became 11–12 kΩ for all three types of electrodes. Thus, all electrodes showed similar results. It was concluded that the copper-based textile electrodes were more suitable than the silver-based textile electrodes and comparable to commercial electrodes regarding impedance in all three skin conditions. [ABSTRACT FROM AUTHOR]

In this paper, wristband electrodes for hand-to-hand bioimpedance measurements are investigated. The proposed electrodes consist of a stretchable conductive knitted fabric. Different implementations have been developed and compared with Ag/AgCl commercial electrodes. Hand-to-hand measurements at 50 kHz on forty healthy subjects have been carried out and the Passing–Bablok regression method has been exploited to compare the proposed textile electrodes with commercial ones. It is demonstrated that the proposed designs guarantee reliable measurements and easy and comfortable use, thus representing an excellent solution for the development of a wearable bioimpedance measurement system. [ABSTRACT FROM AUTHOR]

In recent days, a digestive abnormality is common due to modern life-style and food habits followed. For every ten adults in the world, four suffer from functional gastrointestinal (GI) disorders of varying severity. Further, this is demonstrated by a study of more than 73,000 people across 33 countries. Also, the subjects who have undergone surgery/medication may feel healthy and they cannot feel or realize the internal health disorders, resulting in severe consequences. In this regard, an electrogastrogram (EGG) has gained more significance since it is non-invasive and involves an easy process for screening digestive abnormalities. EGGs are electrical signals, which have strong association with digestion. Also, the EGG can be recorded using non-invasive/surface electrodes. In this work, two different conductive textile materials, namely stainless-steel fibers and Copper–Nickel-plated nylon, are utilised to fabricate non-invasive electrodes. Further, the developed electrodes are placed on the abdomen over the stomach and the EGG signals are acquired from healthy individuals. Also, various time and frequency domain features are extracted from two different EGG signals acquired using developed electrodes with different materials and are analysed. Additionally, the XAI, namely Shapley Additive Explanation (SHAP), technique is utilised to analyse and test the efficacy of the developed textile-based electrodes and to select the best electrode for EGG signal acquisition. This work appears to be highly significant since the developed electrode selected using the XAI tool shall possess a wide scope in wearable applications. [ABSTRACT FROM AUTHOR]

Recording electrical muscle activity using a dense matrix of detection points (high-density electromyography, EMG) is of interest in a range of different applications, from human-machine interfacing to rehabilitation and clinical assessment. The wider application of high-density EMG is, however, limited as the clinical interfaces are not convenient for practical use (e.g., require conductive gel/cream). In the present study, we describe a novel dry electrode (TEX) in which the matrix of sensing pads is screen printed on textile and then coated with a soft polymer to ensure good skin-electrode contact. To benchmark the novel solution, an identical electrode was produced using state-of-the-art technology (polyethylene terephthalate with hydrogel, PET) and a process that ensured a high-quality sample. The two electrodes were then compared in terms of signal quality as well as functional application. The tests showed that the signals collected using PET and TEX were characterised by similar spectra, magnitude, spatial distribution and signal-to-noise ratio. The electrodes were used by seven healthy subjects and an amputee participant to recognise seven hand gestures, leading to similar performance during offline analysis and online control. The comprehensive assessment, therefore, demonstrated that the proposed textile interface is an attractive solution for practical applications. [ABSTRACT FROM AUTHOR]

This report aims to provide a patent landscape analysis on carbon allotrope-based textile electrodes and biosensors to measure biosignals and detect several parameters. Espacenet, a free-of-charge patent database provided by the EPO (European Patent Office) and containing data on more than 140 million patent publications from over 100 countries, was used as the reference database. The patent search was carried out by combining keywords and classification symbols. Both classification schemes (IPC–International Patent Classification and CPC–Cooperative Patent Classification) were used. As a result of this study, a total of 227 patent documents were found between 2002 and 2023. The first patent application claiming a fabric electrode arrangement with carbon black as conductive material was filed in 2002 (and published in 2004) by Philips. 2021 was the year with the highest number of published patent applications, with 36 documents. The United States was ranked first with 126 patent documents. Carbon nanotubes and graphene are the most patented carbon allotrope materials, while body temperature, motion, and heart rate measurements are the main disclosed applications. We also analyzed the Orbit database obtaining 288 patent documents (vs. 227) with only 238 still active records (148 granted and 90 pending applications): the first application by Philips on an electrode arrangement is confirmed, and the patent distribution shows a peak in the period 2016–2020 (146 records available), while today it seems to be stable or even decreasing (“only” 52 records in the half period January 2021–June 2023). This outcome suggests that this material and related technology has reached its maximum exploitation or has not demonstrated a disruptive output.

The development of smart wearable solutions for monitoring daily life health status is increasingly popular, with chest straps and wristbands being predominant. This study introduces a novel sensorized T-shirt design with textile electrodes connected via a knitting technique to a Movesense device. We aimed to investigate the impact of stationary and movement actions on electrocardiography (ECG) and heart rate (HR) measurements using our sensorized T-shirt. Various activities of daily living (ADLs), including sitting, standing, walking, and mopping, were evaluated by comparing our T-shirt with a commercial chest strap. Our findings demonstrate measurement equivalence across ADLs, regardless of the sensing approach. By comparing ECG and HR measurements, we gained valuable insights into the influence of physical activity on sensorized T-shirt development for monitoring. Notably, the ECG signals exhibited remarkable similarity between our sensorized T-shirt and the chest strap, with closely aligned HR distributions during both stationary and movement actions. The average mean absolute percentage error was below 3%, affirming the agreement between the two solutions. These findings underscore the robustness and accuracy of our sensorized T-shirt in monitoring ECG and HR during diverse ADLs, emphasizing the significance of considering physical activity in cardiovascular monitoring research and the development of personal health applications.

Electromyography is a technique to record and analyze signals from muscle tissue. Commonly, gel-based (Ag/AgCl) electrodes are used to detect muscle action potentials. Current gel-based electrode designs, however, do not perform well under constant movement and therefore are less suitable to monitor muscle behavior under everyday activities. Textile electrodes do well under movement and extended use, but produce weaker signals than their gel-based counterparts. This work points towards a reduction of this performance gap when the textile electrodes are designed to fit the target muscle. Four textile electrodes of different sizes and shapes are tested on the biceps brachii of 13 subjects. Signal parameters such as the signal-to-noise ratio and voltage root-mean-square are used to determine the quality of the myoelectric signals generated by these electrodes. Results with statistically significant differences show that the electrode area and alignment to the muscle fibers affect signal quality and strength. These results indicate that target muscle characteristics should dictate the electrode dimensional parameters to optimize surface electromyography signal acquisition. [ABSTRACT FROM AUTHOR]

Neurostimulation delivers electrical pulses to modulate neuromuscular activity. Commonly used in medical interventions from pain relief to rehabilitation, neurostimulation typically uses manually placed hydrogel electrodes over the treated region. However, this method limits interventions requiring frequent, long-term daily use. To address this, novel fully textile electrodes are developed using industrial programmable knitting machines. These electrodes are designed to be washable, reusable, flexible, and breathable, with embedded interconnects. Textile electrodes are made of yarns with stainless steel and PEDOT-coated stainless steel conductive components. The electrodes' performance are compared with gel electrodes, characterizing impedance, sensorimotor stimulation thresholds, recruitment of induced movements, sensation levels, and perceived sensations. The effects of residential wash cycles and continuous use duration are also investigated. The proposed electrodes are found to perform similarly to hydrogel electrodes in all characterized metrics. No degradation in electrode performance is found after at least 30 wash cycles. Electrodes remained functionally intact after 1000 cycles of stretch loading at 50% of break strain. The textile electrodes consistently induced comfortable sensorimotor responses for at least six hours after donning. The proposed textile electrodes offer a novel and effective solution for neurostimulation interventions, paving the way for integration into smart garments and long-term wearable health technologies., (© 2024 Wiley‐VCH GmbH.)

Textile-based surface electromyography (sEMG) electrodes have emerged as a prominent tool in muscle fatigue assessment, marking a significant shift toward innovative, noninvasive methods. This review examines the transition from metallic fibers to novel conductive polymers, elastomers, and advanced material-based electrodes, reflecting on the rapid evolution of materials in sEMG sensor technology. It highlights the pivotal role of materials science in enhancing sensor adaptability, signal accuracy, and longevity, crucial for practical applications in health monitoring, while examining the balance of clinical precision with user comfort. Additionally, it maps the global sEMG research landscape of diverse regional contributors and their impact on technological progress, focusing on the integration of Eastern manufacturing prowess with Western technological innovations and exploring both the opportunities and challenges in this global synergy. The integration of such textile-based sEMG innovations with artificial intelligence, nanotechnology, energy harvesting, and IoT connectivity is also anticipated as future prospects. Such advancements are poised to revolutionize personalized preventive healthcare. As the exploration of textile-based sEMG electrodes continues, the transformative potential not only promises to revolutionize integrated wellness and preventive healthcare but also signifies a seamless transition from laboratory innovations to real-world applications in sports medicine, envisioning the future of truly wearable material technologies.

• Supernatant and sediment parts of Ti 3 C 2 Tx MXene were obtained after the synthesis. • Drop-casting technique was used to fabricate the cotton fabric supercapacitor electrodes. • The effect of post-synthesis parameters and concentration of MXene dispersion on the electrochemical properties of fabric electrodes was investigated. • MXene-coated high-performance cotton fabric supercapacitor electrode was obtained. This study investigates the electrochemical performance of Ti 3 C 2 T x MXene-coated cotton fabric electrodes for supercapacitor applications. The sediment and supernatant parts of synthesized Ti 3 C 2 T x MXene were applied onto cotton substrates through a drop-casting technique at various concentrations to explore the influence of MXene dispersion density on the structural, morphological, and electrochemical properties of the fabric electrodes. Findings indicate that the lower-concentration dispersions not only improve the structural integrity of the coatings but also enhance their electrochemical functionality. The fabric electrodes fabricated from MXene supernatant exhibited significantly lower electrical resistance (7.3 Ω sq−1) and higher specific capacitance, reaching 488 F g −1 at a current density of 0.5 A g −1. The study demonstrates the potential of MXene-coated fabrics as adaptable and efficient energy solutions for wearable technologies, highlighting that tuning the concentration and post-synthesis parameters of MXene dispersions can effectively alter their electrochemical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, wristband electrodes for hand-to-hand bioimpedance measurements are investigated. The proposed electrodes consist of a stretchable conductive knitted fabric. Different implementations have been developed and compared with Ag/AgCl commercial electrodes. Hand-to-hand measurements at 50 kHz on forty healthy subjects have been carried out and the Passing–Bablok regression method has been exploited to compare the proposed textile electrodes with commercial ones. It is demonstrated that the proposed designs guarantee reliable measurements and easy and comfortable use, thus representing an excellent solution for the development of a wearable bioimpedance measurement system.

Electrical stimulation can be used for the treatment of various nerve and muscle injuries as well as acute and chronic pain conditions. An electrical pulse is applied to a muscle or nerve to activate excitable tissue using internal or external electrodes with the aim of building muscle strength, artificially creating or supporting limb movement or reducing pain. Textile electrodes offer several advantages over conventionally used disposable surface electrodes: they are flexible and re-usable and they do not require hydrogels, thereby avoiding skin irritation and allergic reactions and enhancing user comfort. This article presents a literature review that assesses the state of research on textile electrode constructions. Based on the review, production approaches and designs are compared, methods for evaluating stimulation discomfort and pain are proposed and issues related to user compliance are discussed. The article concludes with suggestions for future work focused on investigating the impacts of textile-based electrode parameters on comfort, convenience and ease of use. [ABSTRACT FROM AUTHOR]

In the area of biomedical signal monitoring, wearable electronics represents a dynamically growing field with a significant impact on the market of commercial products of biomedical signal monitoring and acquisition, as well as consumer electronic for vital functions monitoring. Since the electrodes are perceived as one of the most important part of the biomedical signal monitoring, they have been one of the most frequent subjects in the research community. Electronic textile (e-textile), also called smart textile represents a modern trend in the wearable electronics, integrating of functional materials with common clothing with the goal to realize the devices, which include sensors, antennas, energy harvesters and advanced textiles for self-cooling and heating. The area of textile electrodes and e-textile is perceived as a multidisciplinary field, integrating material engineering, chemistry, and biomedical engineering. In this review, we provide a comprehensive view on this area. This multidisciplinary review integrates the e-textile characteristics, materials and manufacturing of the textile electrodes, noise influence on the e-textiles performance, and mainly applications of the textile electrodes for biomedical signal monitoring and acquisition, including pressure sensors, electrocardiography, electromyography, electroencephalography and electrooculography monitoring. [ABSTRACT FROM AUTHOR]

Fluid overload is a chronic medical condition that affects over six million Americans with conditions such as congestive heart failure, end-stage renal disease, and lymphedema. Remote management of fluid overload continues to be a leading clinical challenge. Bioimpedance is one technique that can be used to estimate the hydration of tissue and track it over time. However, commercially available bioimpedance measurement systems are bulky, expensive, and rely on Ag/AgCl electrodes that dry out and can irritate the skin. The use of bioimpedance today is therefore limited to clinical and research settings, with measurements performed at daily intervals or over short periods of time rather than continuously and long-term. This paper proposes using wearable calf bioimpedance measurements integrated into a compression sock for long-term fluid overload management. A PCB was developed using standard measurement techniques that measures the calf bioimpedance using a custom analog front-end built around an AD8302 gain-phase detection chip. Data is transmitted wirelessly via Bluetooth Low Energy to an iOS device using a custom iOS app. Bioimpedance data were collected both from the wearable system and a commercial measurement system (ImpediMed SFB7) using RRC networks, Ag/AgCl electrodes, and the textile compression sock. Bioimpedance data collected from the wearable system showed close agreement with data from the SFB7 when using RRC networks and in five healthy human subjects with Ag/AgCl electrodes. However, when using the textile compression sock the wearable system had worse precision than the SFB7 (4% run to run compared to

Recording electrical muscle activity using a dense matrix of detection points (high-density electromyography, EMG) is of interest in a range of different applications, from human-machine interfacing to rehabilitation and clinical assessment. The wider application of high-density EMG is, however, limited as the clinical interfaces are not convenient for practical use (e.g., require conductive gel/cream). In the present study, we describe a novel dry electrode (TEX) in which the matrix of sensing pads is screen printed on textile and then coated with a soft polymer to ensure good skin-electrode contact. To benchmark the novel solution, an identical electrode was produced using state-of-the-art technology (polyethylene terephthalate with hydrogel, PET) and a process that ensured a high-quality sample. The two electrodes were then compared in terms of signal quality as well as functional application. The tests showed that the signals collected using PET and TEX were characterised by similar spectra, magnitude, spatial distribution and signal-to-noise ratio. The electrodes were used by seven healthy subjects and an amputee participant to recognise seven hand gestures, leading to similar performance during offline analysis and online control. The comprehensive assessment, therefore, demonstrated that the proposed textile interface is an attractive solution for practical applications.

Achieving high energy storage performance and fast rate capability at the same time is one of the most critical challenges in battery technology. Here, a high‐performance textile cathode with notable specific/areal capacities and high rate capability through an interfacial interaction‐mediated assembly that can directly bridge all interfaces existing between textile and conductive materials and between conductive and active materials, minimizing unnecessary insulating organics is reported. First, amine (NH2)‐ and carboxylic acid (COOH)‐functionalized multiwalled carbon nanotubes (MWNTs) are alternately layer‐by‐layer (LbL)‐assembled onto cellulose textiles for the preparation of conductive textiles using hydrogen bonding interactions. Dioleamide‐stabilized LiFePO4 nanoparticles (DA‐LFP NPs) with high crystallinity and high dispersion stability in organic media are consecutively LbL‐assembled with MWNT‐NH2 onto conductive textiles through ligand replacement between native DA ligands bound to the surface of the LFP NPs and NH2 groups of MWNTs. In this case, 35 nm sized LFP NPs are densely and uniformly adsorbed onto all regions of the textile, and additionally, their areal capacities are increased according to the deposition number without a significant loss of charge transfer kinetics. The formed textile cathodes exhibit remarkable specific/areal capacities (196 mAh g−1/8.3 mAh cm−2 at 0.1 C) and high rate capability with highly flexible mechanical properties. [ABSTRACT FROM AUTHOR]

Muscle activity monitoring in dynamic conditions is a crucial need in different scenarios, ranging from sport to rehabilitation science and applied physiology. The acquisition of surface electromyographic (sEMG) signals by means of grids of electrodes (High-Density sEMG, HD-sEMG) allows obtaining relevant information on muscle function and recruitment strategies. During dynamic conditions, this possibility demands both a wearable and miniaturized acquisition system and a system of electrodes easy to wear, assuring a stable electrode-skin interface. While recent advancements have been made on the former issue, detection systems specifically designed for dynamic conditions are at best incipient. The aim of this work is to design, characterize, and test a wearable, HD-sEMG detection system based on textile technology. A 32-electrodes, 15 mm inter-electrode distance textile grid was designed and prototyped. The electrical properties of the material constituting the detection system and of the electrode-skin interface were characterized. The quality of sEMG signals was assessed in both static and dynamic contractions. The performance of the textile detection system was comparable to that of conventional systems in terms of stability of the traces, properties of the electrode-skin interface and quality of the collected sEMG signals during quasi-isometric and highly dynamic tasks. [ABSTRACT FROM AUTHOR]

The improvement of human health condition is an important objective that remains relevant since the origin of human being. Currently, cardiovascular diseases are the first cause of death worldwide. For this reason, permanent real-time monitoring of heart activity (Electrocardiogram: ECG), its analysis and alerting of concerned person is a solution to decrease the death toll provoked by heart diseases. ECG signal of medical quality is necessary for permanent monitoring and accurate heart examining. It can be obtained from instrumented underwear only if it is equipped with high quality, flexible textile based electrodes guaranteeing low contact resistance between the skin and them. This work is therefore devoted to the design and test of wearable textile embroidered bands following defined protocol for ECG long-term monitoring. These bands were investigated in three configurations: band without any adding layer to protect lines between electrodes and the connector, band with lines protected by simple yarn, band with lines protected with thermoplastic polyurethane (TPU). Bands were worn around chest by healthy subjects in a sitting position and ECG signals were acquired by an Arduino-based device and assessed. Washability tests of connected underwear were carried out over 50 washing cycles in a domestic machine and by using a commercial detergent. Influence of encapsulation process on the electrical properties of textile electrodes during repetitive washing process has also been investigated and analyzed. All the ECG signals acquired and recorded have been reviewed by a cardiologist in order to validate their quality required for accurate diagnosis.

Abstract Background Wearable textile electrodes for the detection of biopotentials are a promising tool for the monitoring and early diagnosis of chronic diseases. We present a comparative study of the electrical characteristics of four textile electrodes manufactured from common fabrics treated with a conductive polymer, a commercial fabric, and disposable Ag/AgCl electrodes. These characteristics will allow identifying the performance of the materials when used as ECG electrodes. The electrodes were subjected to different electrical tests, and complemented with conductivity calculations and microscopic images to determine their feasibility in the detection of ECG signals. Methods We evaluated four electrical characteristics: contact impedance, electrode polarization, noise, and long-term performance. We analyzed PEDOT:PSS treated fabrics based on cotton, cotton–polyester, lycra and polyester; also a commercial fabric made of silver-plated nylon Shielde® Med-Tex P130, and commercial Ag/AgCl electrodes. We calculated conductivity from the surface resistance and, analyzed their surface at a microscopic level. Rwizard was used in the statistical analysis. Results The results showed that textile electrodes treated with PEDOT:PSS are suitable for the detection of ECG signals. The error detecting features of the ECG signal was lower than 2% and the electrodes kept working properly after 36 h of continuous use. Even though the contact impedance and the polarization level in textile electrodes were greater than in commercial electrodes, these parameters did not affect the acquisition of the ECG signals. Fabrics conductivity calculations were consistent to the contact impedance.

In this paper the results of the study performed on dry textile electrodes for bio-impedance measurements are reported. The use of two different conductive fabrics is investigated: a silver-plated bi-elastic knitted fabric and a bi-layer structure comprising a layer of a silver-plated knitted fabric and a layer of conductive silicone. In this latter, the presence of the silicone layer guarantees a good contact with the skin, which is a fundamental condition for accurate bio-impedance measurements, and preserves the silver by oxidation due to sweat. The fabricated textile electrodes have been sewn on elastic cuffs and two different relative positions of the current and voltage electrodes have been investigated. The proposed cuffs are suitable to be embedded into a t-shirt for continuous and real-time bio-impedance measurements. The reliability of the developed prototypes is validated by comparison with data obtained from Ag/AgCl commercial electrodes. Promising results have been obtained for both the investigated conductive fabrics. [ABSTRACT FROM AUTHOR]

Electrocardiogram (ECG) signal monitoring is one of the essential techniques for determining the physiological state of human beings. Long-term ECG monitoring is very much essential for the diagnosis and treatment of infrequent arrhythmic episodes. Although, most of the wearable microelectronic ECG implementations employ the well-established surface electrodes technology for bio-potential recordings; they are found to be susceptible to skin irritation and influence the skin-contact impedance to larger extent in long-term monitoring applications. Integration of such sensors into wearable intelligent biomedical clothing is not feasible. This specific research study determines the application of two different conductive textile fabric materials, namely, the woven conductive silver and conductive knitted jersey as dry textile electrodes for ECG biopotential acquisition. The skin-electrode contact impedance measurements for both electrodes presented reduced skin-contact impedance of less than 1 $\text{M}\Omega $ /cm2 compared to 1–5 $\text{M}\Omega $ /cm2 as reported in literature. The performance of the proposed textile sensors is evaluated qualitatively through visual inspection and quantitatively using metrics such as power spectral density, kurtosis, baseline wander analysis, and signal-to-noise ratio (SNR). The obtained quantitative measures were compared with standard clinical grade conductive-gel based disposable Ag/AgCl surface electrodes. The simulation and comparison studies showed that, the proposed textile electrodes exhibit acceptable performance for ECG acquisition and in some instances improved performance than the traditional commercial disposable gel-based surface electrodes. [ABSTRACT FROM AUTHOR]

This systematic review concerns the use of smart textiles enabled applications based on myoelectric activity. Electromyography (EMG) is the technique for recording and evaluating electric signals related to muscle activity (myoelectric). EMG is a well-established technique that provides a wealth of information for clinical diagnosis, monitoring, and treatment. Introducing sensor systems that allow for ubiquitous monitoring of health conditions using textile integrated solutions not only opens possibilities for ambulatory, long-term, and continuous health monitoring outside the hospital, but also for autonomous self-administration. Textile-based electrodes have demonstrated potential as a fully operational alternative to 'standard' Ag/AgCl electrodes for recording surface electromyography (sEMG) signals. As a substitute for Ag/AgCl electrodes fastened to the skin by taping or pre-gluing adhesive, textile-based electrodes have the advantages of being soft, flexible, and air permeable; thus, they have advantages in medicine and health monitoring, especially when self-administration, real-time, and long-term monitoring is required. Such advances have been achieved through various smart textile techniques; for instance, adding functions in textiles, including fibers, yarns, and fabrics, and various methods for incorporating functionality into textiles, such as knitting, weaving, embroidery, and coating. In this work, we reviewed articles from a textile perspective to provide an overview of sEMG applications enabled by smart textile strategies. The overview is based on a literature evaluation of 41 articles published in both peer-reviewed journals and conference proceedings focusing on electrode materials, fabrication methods, construction, and sEMG applications. We introduce four textile integration levels to further describe the various textile electrode sEMG applications reported in the reviewed literature. We conclude with suggestions for future work along with recommendations for the reporting of essential benchmarking information in current and future textile electrode applications. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are the most frequent cause of death worldwide. Cases of cardiac arrest can often be attributed to undetected cardiac arrhythmia. Detecting rare episodes of arrhythmia necessitates long-term ECG measurements along days or weeks. However, due to the relatively small number of electrodes used for these ECGs, abnormal episodes can still go unrecognized. This article thus describes the development of underwear with ten inbuilt textile ECG electrodes, allowing for the measurement of long-term 12-lead ECG. As against the constructs of other research groups, the position of electrodes offers the same detection directions as the common 12-lead ECG equipment in hospitals or medical practices. Long-term tests have shown the suitability of the sensory underwear variants for men and women to detect reliable ECG signals without disturbing the patients’ comfort.

Wearable physiological monitoring systems are becoming increasingly prevalent in the push toward autonomous health monitoring and offer new modalities for playful and purposeful interaction within human computer interaction (HCI). Sensing systems that can be integrated into garments and, therefore, daily activities offer promising pathways toward ubiquitous integration. The electrocardiogram (ECG) signal is commonly monitored in healthcare and is increasingly utilized as a method of determining emotional and psychological state; however, the complete ECG waveform with the P, Q, R, S, and T peaks is not commonly used, due to the challenges associated with collecting the full waveform with wearable systems. We present woven textile electrodes as an option for garment-integrated ECG monitoring systems that are capable of capturing the complete ECG waveform. In this work, we present the changes in the peak detection performance caused by different sizes, patterns, and thread types with data from 10 human participants. These testing results provide empirically-derived guidelines for future woven textile electrodes, present a path forward for assessing design decisions, and highlight the importance of testing novel wearable sensor systems with more than a single individual.

Multi-channel measurements from the maternal abdomen acquired by means of dry electrodes can be employed to promote long-term monitoring of fetal heart rate (fHR). The signals acquired with this type of electrode have a lower signal-to-noise ratio and different artifacts compared to signals acquired with conventional wet electrodes. Therefore, starting from the benchmark algorithm with the best performance for fHR estimation proposed by Varanini et al., we propose a new method specifically designed to remove artifacts typical of dry-electrode recordings. To test the algorithm, experimental textile electrodes were employed that produce artifacts typical of dry and capacitive electrodes. The proposed solution is based on a hybrid (hardware and software) pre-processing step designed specifically to remove the disturbing component typical of signals acquired with these electrodes (triboelectricity artifacts and amplitude modulations). The following main processing steps consist of the removal of the maternal ECG by blind source separation, the enhancement of the fetal ECG and identification of the fetal QRS complexes. Main processing is designed to be robust to the high-amplitude motion artifacts that corrupt the acquisition. The obtained denoising system was compared with the benchmark algorithm both on semi-simulated and on real data. The performance, quantified by means of sensitivity, F1-score and root-mean-square error metrics, outperforms the performance obtained with the original method available in the literature. This result proves that the design of a dedicated processing system based on the signal characteristics is necessary for reliable and accurate estimation of the fHR using dry, textile electrodes.

In recent years, the variety of textile electrodes developed for electrophysiological signal detection has increased rapidly. Among the applications that could benefit from this advancement, those based on surface electromyography (sEMG) are particularly relevant in rehabilitation, training, and muscle function assessment. In this work, we validate the performance of polymer-based screen-printed textile electrodes for sEMG signal detection. We obtained these electrodes by depositing poly-3,4-ethylenedioxythiophene doped with poly(styrene sulfonate) (PEDOT:PSS) onto cotton fabric, and then selectively changing the physical properties of the textile substrate. The manufacturing costs are low and this process meets the requirements of textile-industry production lines. The validation of these electrodes was based on their functional and electrical characteristics, assessed for two different electrode sizes and three skin-interface conditions (dry, solid hydrogel, or saline solution), and compared to those of conventional disposable gelled electrodes. Results show high similarity in terms of noise amplitude and electrode-skin impedance between the conventional and textile electrodes with the addition of solid hydrogel or saline solution. Furthermore, we compared the shape of the electrically induced sEMG, as detected by conventional and textile electrodes from tibialis anterior. The comparison yielded an $\text{R}^{\textsf {2}}$ value higher than 97% for all measurement conditions. Preliminary tests in dynamic conditions (walking) revealed the exploitability of the proposed electrode technology with saline application for the monitoring of sEMG for up to 35 min of activity. These results suggest that the proposed screen-printed textile electrodes may be an effective alternative to the conventional gelled electrodes for sEMG acquisition, thereby providing new opportunities in clinical and wellness fields. [ABSTRACT FROM AUTHOR]