Sarah Brady

Integration of analytical measurements and wireless communications—Current issues and future strategies

Rapid developments in wireless communications are opening up opportunities for new ways to perform many types of analytical measurements that up to now have been restricted in scope due to the need to have access to centralised facilities. This paper will address both the potential for new applications and the challenges that currently inhibit more widespread integration of wireless communications with autonomous sensors and analytical devices. Key issues are identified and strategies for closer integration of analytical information and wireless communications systems discussed.

Initial development and testing of a novel foam-based pressure sensor for wearable sensing

BackgroundThis paper provides an overview of initial research conducted in the development of pressure-sensitive foam and its application in wearable sensing. The foam sensor is composed of polypyrrole-coated polyurethane foam, which exhibits a piezo-resistive reaction when exposed to electrical current. The use of this polymer-coated foam is attractive for wearable sensing due to the sensors retention of desirable mechanical properties similar to those exhibited by textile structures.MethodsThe development of the foam sensor is described, as well as the development of a prototype sensing garment with sensors in several areas on the torso to measure breathing, shoulder movement, neck movement, and scapula pressure. Sensor properties were characterized, and data from pilot tests was examined visually.ResultsThe foam exhibits a positive linear conductance response to increased pressure. Torso tests show that it responds in a predictable and measurable manner to breathing, shoulder movement, neck movement, and scapula pressure.ConclusionThe polypyrrole foam shows considerable promise as a sensor for medical, wearable, and ubiquitous computing applications. Further investigation of the foams consistency of response, durability over time, and specificity of response is necessary.

Garment-based monitoring of respiration rate using a foam pressure sensor

Comfortable body monitoring is crucial to many wearable devices. However, many traditional sensors impede wearability by their physical structure or functional requirements. This paper presents the application of a novel garment-integrated foam-based pressure sensor used for monitoring the wearers respiration rate. The sensor was evaluated in a torso garment during a 10-minute treadmill test. Results were accurate within one breath per minute, as compared to a standard airflow breathing test.

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.

Body Sensor Network based on Soft Polymer Sensors and Wireless Communications

Wireless communications is now completely pervasive, and already is used in many guises by people in everyday life. However until now, the information exchanged has been mainly standard electronic forms of standard data such as text, images, video. More recently, attention has been increasingly focused on sensor-based data, which presents rich new areas for applications and research, particularly in the area of life-logging applications. Thus, focus must shift to developing new and novel sensor layers to bridge this interface between the real world of the body and the digital world of communications. The easiest means to do this is with wearable sensors, but this in turn raises the issue of ‘comfortable’ body monitoring systems. If the “wearable” device is uncomfortable then user compliance will be greatly compromised. At present many conventional sensors are unsuitable for wearable body monitoring devices, however, in this paper, we present a prototype wearable device which was used and compared to an established non-wearable method for monitoring breathing frequency.

Bio-sensing textiles - Wearable Chemical Biosensors for Health Monitoring

In recent years much progress has been made in the integration of physical transducers into clothing e.g. breathing rate, heart rate and temperature [1]. The integration of chemical sensing into textiles adds a new dimension to the field of smart clothing. Wearable chemical sensors may be used to provide valuable information about the wearer’s health, monitoring the wearer during their daily routine within their natural environment. In addition to physiological measurements chemical sensors may also be used to monitor the wearer’s surrounding environment, identifying safety concerns and detecting threats. Whether the clothes are looking into the wearer’s personal health status or looking out into the surroundings, chemical sensing calls for a novel approach to sensor and textile integration. In contrast to physical sensors, chemical sensors and biosensors depend on selective reactions happening at an active surface which must be directly exposed to a sample. Therefore issues of fluid handling, calibration and safety must be considered. This paper discusses the constraints in integrating chemical sensors into a textile substrate. Methods of fluid control using inherently conducting polymers (ICPs) are discussed and a pH textile sensor is presented. This sensor uses colorimetric techniques using LEDs controlled by a wireless platform. Some of the potential applications of wearable chemical sensors are discussed.

Wearable sensors for monitoring sports performance and training

Textile based devices for biochemical analysis of body fluids represent a new development in the area of wearable sensors. This paper outlines the development of a fluid handling system and wireless sensors for the real-time analysis of sweat pH and sodium levels during exercise. Liquid is drawn into the system using a moisture wicking material and passive pump. The sensor then displays pH induced colorimetric changes, which are recorded using an optical detection system. The device has been tested under laboratory conditions and can easily detect increments of 0.2 pH units. At present, changes in sodium content are determined using a specially constructed classic ion selective electrode and reference electrode, combined to form a single probe. This is placed in contact with the fabric of the fluid handling system in order to obtain a real-time potentiometric sodium measurement. Both devices have successfully been used for the investigation of sweat composition during on-body trials.

Combining wireless with wearable technology for the development of on-body networks

In the area of wearable devices, the issue of comfortable body monitoring is of up most importance. However conventional sensors are generally unsuitable for wearable body monitoring devices either due to their physical structure or their functional requirements. This paper presents a prototype wearable device whereby the breathing rate of a number of subjects were monitored and compared to an established method. The prototype took the form of a skin-tight Lycra-based t-shirt into which a polypyrrole-coated polyurethane foam sensor and a wireless communication platform was incorporated. The sensor was soft and compressible, retaining the desirable mechanical properties of the original structure, making it attractive for wearable applications, such as monitoring breathing during exercise. Information from this sensor was wirelessly transmitted to a base-station for storage and display purposes. This paper is focused on the successful integration of all these components into a wearable wireless sensor and evaluates its ability to measure breathing frequency

Optimisation of a novel glass-alginate hydrogel for the treatment of intracranial aneurysms

The current gold standard for aneurysm treatment is endovascular coiling. However, recurrence is observed in over 20% of cases. A novel hydrogel has been developed to treat aneurysms. This hydrogel is composed of a polymeric alginate, a novel ion releasing glass and glucono-delta-lactone. This is an internally setting alginate hydrogel, wherein the setting rate can be controlled by both the glass and the alginate chemistry. The aim of this work is to examine the effect of each component of the hydrogel and optimise the composition of the hydrogel, specifically the alginate molecular weight, M/G ratio and concentration. The effects of gamma sterilisation will also be examined. The results show that alginate concentration, chemical composition and molecular weight affect the compressive strength, working time, hardening time and deliverability of the hydrogel. Gamma irradiation of the alginate reduces the molecular weight, which has a negative effect on the usability of this hydrogel.

Surface modification of a novel glass to optimise strength and deliverability of an injectable alginate composite

It is estimated that 1–6% of the adult population have an intracranial aneurysm. Aneurysm coiling is the current preferred treatment method; however, over 20% of coiled aneurysms recur. A novel glass–alginate composite hydrogel has been developed to treat aneurysms, which is designed to completely fill the aneurysm space and prevent aneurysm recurrence. This hydrogel is composed of a polymeric alginate, a novel bioactive glass and glucono-delta-lactone. This novel injectable hydrogel exhibits characteristics suitable for the treatment of cerebral aneurysms. However, poor hydrophilicity of the glass phase results in inhomogeneity and agglomerate formation within the composite, resulting in suboptimal deliverability and strength. This study examines the effect of surface modification of the glass particles using an acid washing technique, designed to increase glass surface hydrophilicity resulting in a homogeneous sample. This study found that acid washing of the glass not only decreased agglomeration and inhomogeneity but also lengthened working times and increased strength of the resultant hydrogel. This lengthened working time, allowed for an increased glass content and, as a result, further increased compressive strength and radiopacity of the resultant hydrogel. Glass particle size analysis revealed that the relative quantity of fine particles was reduced. Surface analysis of the glass particles revealed an increase in hydrophilic silanol groups and increased surface network connectivity. These factors, combined with a decreased surface calcium and an increased surface gallium content, are postulated as the likely reasons for the observed increased strength, working time and hardening time.