Li Guo

Herein, we report a biofriendly, air‐operating electrochemical platform based on a unipolar coiled carbon nanotube (CNT) yarn artificial muscle that can operate either as an ionic actuator or as an ionotronic strain sensor. The device comprises two coiled CNT yarn electrodes coated with complementary ion‐selective eutectogels, consisting of fixed‐charge polymer networks swollen with a diluted deep eutectic solvent (DES), enabling selective ion transport. Under an applied potential difference, the complementary electrochemical responses of both electrodes produce synchronized unipolar contraction, whereas in sensing mode the device generates a strain‐dependent open‐circuit voltage (OCV) variation. In actuation mode, the device achieves a maximal reversible contractile stroke of 2.9% under a 90 mN pre‐load. In sensing mode, it operates as a self‐powered strain sensor with a sensitivity of 0.5 mV.% ⁻¹ . Poisson–Nernst–Planck modelling is consistent with the proposed mechanism of strain‐induced ion redistribution within the quasi‐solid‐state matrix. Two yarn artificial muscles were woven into a custom‐made, bi‐stretch auxetic structure with a folded zigzag geometry, enabling parallel actuation and strain monitoring, delivering peak‐to‐peak OCV signals of 4 mV at 10% extension. Finally, we demonstrate a wireless wearable armband for real‐time motion monitoring, highlighting the potential of this platform for smart fabrics, wearable electronics, and adaptive soft robotics.

Background: An increasing number of rehabilitation technologies are being developed to support upper limb rehabilitation after stroke, with smart textile solutions for surface electromyography (sEMG) emerging as a promising approach. Early end-user involvement is crucial for developing user-friendly and clinically valid rehabilitation tools. Objective: This study aims to refine and evaluate the prototype design and usability of a smart textile biofeedback system for self-administered upper limb training after stroke. Methods: The training system includes a knitted smart textile sleeve with integrated electrodes over the forearm muscles, an sEMG unit, and tablet-based biofeedback software. An iterative co-design process was followed, including initial testing, demonstration sessions with end users (9 clinicians and 10 individuals with stroke), and a final evaluation of the co-design process. Participants’ experiences were gathered through semistructured interviews, analyzed using content analysis, and the User Experience Questionnaire. The co-design team included experts in stroke rehabilitation, textile engineering, biomedical engineering, software development, and human factors, as well as a research partner with lived experience after stroke. Results: The perspectives of the end users and the expert team were collectively integrated into prototype refinements of the sleeve and training software to meet the needs of the intended target group. The experiences of end users formed 2 main categories: “This could be an exciting new training tool for stroke rehabilitation” and “The tool works well, but some changes could enhance independent training.” End users found the smart textile sleeve and biofeedback system easy to use and saw potential for integrating it into their training routines. Both end-user groups rated the system as attractive, stimulating, and novel. Conclusions: The results of this study establish a necessary ground toward the development of a smart textile sEMG biofeedback system for self-administered upper limb training after stroke. Findings from the co-design process support the continued development and evaluation of the system as a self-administered upper limb training tool for individuals living with stroke.

Electrotactile stimulation can evoke a wide range of sensations, including taps, squeezes, and strokes. Although verbal descriptors are available for vibrotactile and ultrasound stimuli, a comprehensive list has not been developed for electrotactile experiences. To address this, we used a text normalization approach to generate descriptors for wearable electrotactile research and design. In Experiment 1 (N=14), Dutch participants provided 504 open-ended descriptions in response to 36 electrotactile stimuli on the forearm. These were processed into 71 unique English descriptors with considerable inter-rater reliability. Experiment 2 (N=24) evaluated a reduced list of 42 descriptors under additional stimulation conditions, showing robust and consistent descriptor usage, also across varying stimulus intensities. This list partially overlaps with previous non-electrotactile descriptor lists but also includes terms that seem to be unique to electrotactile sensations. Altogether, our findings contribute to the development of common verbal descriptors for electrotactile stimulation, supporting future wearable haptic research and design.

Background: Phantom limb pain (PLP) affects many individuals with limb loss and often requires long-term treatment. Phantom motor execution (PME), which involves decoding phantom movements through myoelectric pattern recognition and real-time feedback, often delivered via extended reality (XR), has shown promise in reducing PLP. However, its use in home settings is limited by usability and the cost of traditional disposable (Ag/AgCl) electrodes. Textile-electrode systems may offer a more user-friendly and sustainable alternative, improving the practicality of home-based PLP training. Objective: This pilot study aimed to explore the potential of using a textile-electrode system for self-administered, home-based PME interventions, focusing on user perceptions and experiences through qualitative data. Methods: Five participants with lower and one with upper limb amputations were provided with a textile-electrode system ( Textrode-band , a study-specific prototype developed at the University of Borås) connected to a PME system (Neuromotus, Integrum AB, Sweden). Participants used the system at home for 24 weeks: 12 weeks of guided training (video sessions and mobile reminders), followed by 12 weeks of unsupervised training with only a weekly emailed training plan. The primary outcome was user acceptance and usability of the system, assessed through semi-structured interviews. Secondary outcomes included training frequency and continuity over two intervention periods. Self-reported PLP and quality of life data were collected to support interpretation but are not reported here. Results: Participants generally found the textile-electrode system comfortable, easy to use, and feasible for independent use at home. Two participants reported reductions in PLP intensity or frequency, and one described improved sleep quality and several reported that the system allowed them to integrate the training into daily routines, improving their sense of control and self-management. However, some challenges with motivation and consistency, especially during the unsupervised phase, indicating the need for ongoing support. Conclusion: The textile-electrode system shows potential to support self-administered, home-based PME offering a user-friendly and practical alternative to traditional electrodes. Future research should focus on improving system robustness, integrating engaging training strategies, and developing support frameworks that balance user independence with necessary guidance. The findings also provide insights into advancing home-based rehabilitation for other neuromuscular conditions requiring long-term rehabilitation.

Textile bioelectronic interfaces are emerging as wearable platforms for continuous physiological sensing, rehabilitation, and human–machine interaction. By integrating functional materials into textiles, electrodes and sensors can become part of the garment itself, forming a deformable interface with the body. Using surface electromyography (sEMG) acquired through textile-integrated electrodes as an illustrative case, this perspective argues that measured sEMG signals are shaped not only by muscle electrical activity but also by the deformable body–textile–electrode interface, whose state may change during use. Current evaluation of textile bioelectronic interfaces is often output centered, focusing on signal quality and downstream performance, which are necessary but insufficient for assessing whether measured signal patterns remain stable and reliable outside controlled conditions. This perspective proposes representation stability as a complementary evaluation criterion within an interface-centered framework. Representation stability asks whether measured signal patterns remain comparable as the physical sensing interface changes during real use. Within this framework, interface conditions become explicit test variables, with representation stability assessed using pre-specified criteria. Introducing representation stability extends evaluation from an output-centered toward an interface-centered paradigm. This could provide a more systematic basis for understanding, comparing, and ultimately designing textile bioelectronic interfaces that remain reliable under real-use variability.

BACKGROUND An increasing number of rehabilitation technologies are being developed to support upper limb rehabilitation after stroke, with smart textile solutions for surface electromyography (sEMG) emerging as a promising approach. Early end-user involvement is crucial for developing user-friendly and clinically valid rehabilitation tools. OBJECTIVE To refine and evaluate the prototype design and usability of a smart textile biofeedback system for self-administered upper limb training after stroke. METHODS The training system includes a knitted smart textile sleeve with integrated electrodes over the forearm muscles, an sEMG unit, and tablet-based biofeedback software. An iterative co-design process was followed, including initial testing, demo sessions with end-users (nine clinicians and ten individuals with stroke), and a final evaluation of the co-design process. Participants' experiences were gathered through semi-structured interviews, analyzed with content analysis, and the User Experience Questionnaire. The co-design team included experts in stroke rehabilitation, textile engineering, biomedical engineering, software development, and human factors, and a research partner with lived experience after stroke. RESULTS The perspectives of the end-users and expert team were collectively integrated into prototype refinements of the sleeve and training software to meet the needs of the intended target group. The experiences of end-users formed two main categories: “This could be an exciting new training tool for stroke rehabilitation” and “The tool works well, but some changes could enhance independent training.” End-users found the smart textile sleeve and biofeedback system easy to use and saw potential for integrating it into their training routines. Both end-user groups rated the system as attractive, stimulating and novel. CONCLUSIONS The results of this study established a necessary ground towards the development of a smart textile sEMG biofeedback system for self-administered upper limb training after stroke. Findings from the co-design process support the continued development and evaluation of the system as a self-administered upper limb training tool for people living with stroke.

Electrophysiological signals generated during daily activities are essential for monitoring and diagnosing various health conditions. Traditionally, Ag/AgCl electrodes with conductive gels have been used to capture these signals, recording them as electrocardiogram (ECG) and electromyogram (EMG). However, gelled electrodes glued to the skin presents challenges related to placement and are uncomfortable to wear for extended recordings. Recent studies have made significant advancements in dry electrodes for electrophysiological signals, mainly focusing on ECG applications with less emphasis on surface EMG (sEMG). To address this gap, this study introduces a novel set of skin‐friendly electrodes made from a blend of conductive carbon black (CB) and partially cross‐linked Ecoflex substrates. By varying the proportions of Ecoflex components A and B, a balance between adequate adhesion and electromechanical properties for good skin contact and long‐term usabi is achieved, owing to the formation of silanol bonds. The CB‐Ecoflex electrodes have been tested through over 50 wash cycles and 100 peel‐offs, demonstrating strong durability and use resilience. Additionally, they maintain good recording conditions for 48 h and when sweat and oil are introduced on the skin. These electrodes consistently deliver reliable performance in 48‐h continuous sEMG recordings, making them suitable for long‐term applications.

Background. The effect of transcutaneous electrical nerve stimulation (TENS) on pain and impression of change was assessed during a 2.5‐hour intervention on the first postoperative days following hip surgery in a randomized, single‐blinded, placebo‐controlled trial involving 30 patients. Methods. Mixed‐frequency TENS (2 Hz/80 Hz) was administered using specially designed pants integrating modular textile electrodes to facilitate stimulation both at rest and during activity. The treatment outcome was assessed by self‐reported pain Numerical Rating Scale (NRS) and Patient Global Impression of Change (PGIC) scores at four time points. The ability to perform a 3‐meter walk test and the use of analgesics were also evaluated. Group comparison and repeated‐measure analysis were carried out using nonparametric statistics. Results. The active TENS group exhibited significantly higher PGIC scores after 30 minutes, which persisted throughout the intervention (all p ≤ 0.001). A reduction in NRS appeared after one hour of active TENS, persisting throughout the intervention (all p ≤ 0.05). The median group differences in pain ratings were greater than the minimum clinically important difference, and the analysis of pain trajectories confirmed clinical significance at the individual level. Moreover, patients in the active TENS group were more likely able to perform a 3‐meter walk test by the end of the intervention (p = 0.04). Analysis of the opioid‐sparing effect of TENS was inconclusive (p = 0.066). No postoperative surgical complications or TENS‐related side effects were observed during the study. Conclusion. Mixed‐frequency TENS integrated in pants could potentially be an interesting addition to the arsenal of treatments for multimodal analgesia following hip surgery. This trial is registered with NCT05678101.

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.