BIOTEX-biosensing textiles for personalised healthcare management.

Textile-based sensors offer an unobtrusive method of continually monitoring physiological parameters during daily activities. Chemical analysis of body fluids, noninvasively, is a novel and exciting area of personalized wearable healthcare systems. BIOTEX was an EU-funded project that aimed to develop textile sensors to measure physiological parameters and the chemical composition of body fluids, with a particular interest in sweat. A wearable sensing system has been developed that integrates a textile-based fluid handling system for sample collection and transport with a number of sensors including sodium, conductivity, and pH sensors. Sensors for sweat rate, ECG, respiration, and blood oxygenation were also developed. For the first time, it has been possible to monitor a number of physiological parameters together with sweat composition in real time. This has been carried out via a network of wearable sensors distributed around the body of a subject user. This has huge implications for the field of sports and human performance and opens a whole new field of research in the clinical setting

Bio-sensing textile based patch with integrated optical detection system for sweat monitoring

Sensors, which can be integrated into clothing and used to measure biochemical changes in body fluids, such as sweat, constitute a major advancement in the area of wearable sensors. Initial applications for such technology exist in personal health and sports performance monitoring. However, sample collection is a complicated matter as analysis must be done in real-time in order to obtain a useful examination of its composition. This work outlines the development of a textile-based fluid handling platform which uses a passive pump to gather sweat and move it through a pre-defined channel for analysis. The system is tested both in vitro and in vivo. In addition, a pH sensor, which depends on the use of a pH sensitive dye and paired emitter-detector LEDs to measure colour changes, has been developed. In vitro and on-body trials have shown that the sensor has the potential to record real-time variations in sweat during exercise

Textile sensors to measure sweat pH and sweat-rate during exercise

Sweat analysis can provide a valuable insight into a person’s well-being. Here we present wearable textile-based sensors that can provide real-time information regarding sweat activity. A pH sensitive dye incorporated into a fabric fluidic system is used to determine sweat pH. To detect the onset of sweat activity a sweat rate sensor is incorporated into a textile substrate. The sensors are integrated into a waistband and controlled by a central unit with wireless connectivity. The use of such sensors for sweat analysis may provide valuable physiological information for applications in sports performance and also in healthcare

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

We report a new method for the real-time quantitative analysis of sodium in human sweat, consolidating sweat collection and analysis in a single, integrated, wearable platform. This temporal data opens up new possibilities in the study of human physiology, broadly applicable from assessing high performance athletes to monitoring Cystic Fibrosis (CF) sufferers. Our compact Sodium Sensor Belt (SSB) consists of a sodium selective Ion Selective Electrode (ISE) integrated into a platform that can be interfaced with the human body during exercise. No skin cleaning regime or sweat storage technology is required as the sweat is continually wicked from the skin to a sensing surface and from there to a storage area via a fabric pump. Our results suggest that after an initial equilibration period, a steady-state sodium plateau concentration was reached. Atomic Absorption Spectroscopy (AAS) was used as a reference method, and this has confirmed the accuracy of the new continuous monitoring approach. The steady-state concentrations observed were found to fall within ranges previously found in the literature, which further validates the approach. Daily calibration repeatability (n 1⁄4 4) was +/- 3.0% RSD and over a three month period reproducibility was +/- 12.1% RSD (n 1⁄4 56). As a further application, we attempted to monitor the sweat of Cystic Fibrosis (CF) sufferers using the same device. We observed high sodium concentrations symptomatic of CF ($60 mM Na+) for two CF patients, with no conclusive results for the remaining patients due to their limited exercising capability, and high viscosity/low volume of sweat produced

Real-time sweat pH monitoring based on a wearable chemical barcode micro-fluidic platform incorporating ionic liquids

This work presents the fabrication, characterisation and the performance of a wearable, robust, flexible and disposable chemical barcode device based on a micro-fluidic platform that incorporates ionic liquid polymer gels (ionogels). The device has been applied to the monitoring of the pH of sweat in real time during an exercise period. The device is an ideal wearable sensor for measuring the pH of sweat since it does not contents any electronic part for fluidic handle or pH detection and because it can be directly incorporated into clothing, head- or wristbands, which are in continuous contact with the skin. In addition, due to the micro-fluidic structure, fresh sweat is continuously passing through the sensing area providing the capability to perform continuous real time analysis. The approach presented here ensures immediate feedback regarding sweat composition. Sweat analysis is attractive for monitoring purposes as it can provide physiological information directly relevant to the health and performance of the wearer without the need for an invasive sampling approac

Developing Disposable EEG Cap for Infant Recordings at the Neonatal Intensive Care Unit

Long-term EEG monitoring in neonatal intensive care units (NICU) is challenged with finding solutions for setting up and maintaining a sufficient recording quality with limited technical experience. The current study evaluates different solutions for the skin–electrode interface and develops a disposable EEG cap for newborn infants. Several alternative materials for the skin–electrode interface were compared to the conventional gel and paste: conductive textiles (textured and woven), conductive Velcro, sponge, super absorbent hydrogel (SAH), and hydro fiber sheets (HF). The comparisons included the assessment of dehydration and recordings of signal quality (skin interphase impedance and powerline (50 Hz) noise) for selected materials. The test recordings were performed using snap electrodes integrated into a forearm sleeve or a forehead band along with skin–electrode interfaces to mimic an EEG cap with the aim of long-term biosignal recording on unprepared skin. In the hydration test, conductive textiles and Velcro performed poorly. While the SAH and HF remained sufficiently hydrated for over 24 h in an incubator-mimicking environment, the sponge material was dehydrated during the first 12 h. Additionally, the SAH was found to have a fragile structure and was electrically prone to artifacts after 12 h. In the electrical impedance and recording comparisons of muscle activity, the results for thick-layer HF were comparable to the conventional gel on unprepared skin. Moreover, the mechanical instability measured by 1–2 Hz and 1–20 Hz normalized relative power spectrum density was comparable with clinical EEG recordings using subdermal electrodes. The results together suggest that thick-layer HF at the skin–electrode interface is an effective candidate for a preparation-free, long-term recording, with many advantages, such as long-lasting recording quality, easy use, and compatibility with sensitive infant skin contact. Keywords: aEEG; NICU; SAH; HFPeer reviewe

Developing Disposable EEG Cap for Infant Recordings at the Neonatal Intensive Care Unit

Long-term EEG monitoring in neonatal intensive care units (NICU) is challenged with finding solutions for setting up and maintaining a sufficient recording quality with limited technical experience. The current study evaluates different solutions for the skin–electrode interface and develops a disposable EEG cap for newborn infants. Several alternative materials for the skin–electrode interface were compared to the conventional gel and paste: conductive textiles (textured and woven), conductive Velcro, sponge, super absorbent hydrogel (SAH), and hydro fiber sheets (HF). The comparisons included the assessment of dehydration and recordings of signal quality (skin interphase impedance and powerline (50 Hz) noise) for selected materials. The test recordings were performed using snap electrodes integrated into a forearm sleeve or a forehead band along with skin–electrode interfaces to mimic an EEG cap with the aim of long-term biosignal recording on unprepared skin. In the hydration test, conductive textiles and Velcro performed poorly. While the SAH and HF remained sufficiently hydrated for over 24 h in an incubator-mimicking environment, the sponge material was dehydrated during the first 12 h. Additionally, the SAH was found to have a fragile structure and was electrically prone to artifacts after 12 h. In the electrical impedance and recording comparisons of muscle activity, the results for thick-layer HF were comparable to the conventional gel on unprepared skin. Moreover, the mechanical instability measured by 1–2 Hz and 1–20 Hz normalized relative power spectrum density was comparable with clinical EEG recordings using subdermal electrodes. The results together suggest that thick-layer HF at the skin–electrode interface is an effective candidate for a preparation-free, long-term recording, with many advantages, such as long-lasting recording quality, easy use, and compatibility with sensitive infant skin contact. Keywords: aEEG; NICU; SAH; HFPeer reviewe

Wearable technology for bio-chemical analysis of body fluids during exercise

This paper details the development of a textile based fluid handling system with integrated wireless biochemical sensors. Such research represents a new advancement in the area of wearable technologies. The system contains pH, sodium and conductivity sensors. It has been demonstrated during on-body trials that the pH sensor has close agreement with measurements obtained using a reference pH probe. Initial investigations into the sodium and conductivity sensors have shown their suitability for integration into the wearable system. It is thought that applications exist in personal health and sports performance and training

Wearable bio and chemical sensors

Chemical and biochemical sensors have experienced tremendous growth in the past decade due to advances in material chemistry combined with the emergence of digital communication technologies and wireless sensor networks (WSNs) [1]. The emergence of wearable chemical and biochemical sensors is a relatively new concept that poses unique challenges to the field of wearable sensing. This is because chemical sensors have a more complex mode of operation, compared to physical transducers, in that they must interact in some manner with specific molecular targets in the sample medium. To understand the challenges in developing wearable chemical and biochemical sensors the traits of these devices will be discussed in this introductory section. Following this the potential parameters of interest are presented and examples of wearable systems are discussed. A range of sampling techniques and methods of chemical sensing are presented along with integration issues and design challenges. Finally, some of the main application areas of this novel technology are discussed