3,422 research outputs found
Stand-alone wearable system for ubiquitous real-time monitoring of muscle activation potentials
Wearable technology is attracting most attention in healthcare for the acquisition of physiological signals. We propose a stand-alone wearable surface ElectroMyoGraphy (sEMG) system for monitoring the muscle activity in real time. With respect to other wearable sEMG devices, the proposed system includes circuits for detecting the muscle activation potentials and it embeds the complete real-time data processing, without using any external device. The system is optimized with respect to power consumption, with a measured battery life that allows for monitoring the activity during the day. Thanks to its compactness and energy autonomy, it can be used outdoor and it provides a pathway to valuable diagnostic data sets for patients during their own day-life. Our system has performances that are comparable to state-of-art wired equipment in the detection of muscle contractions with the advantage of being wearable, compact, and ubiquitous
Smart nanotextiles: materials and their application
Textiles are ubiquitous to us, enveloping our skin and
surroundings. Not only do they provide a protective
shield or act as a comforting cocoon but they also
serve esthetic appeal and cultural importance. Recent
technologies have allowed the traditional functionality
of textiles to be extended. Advances in materials
science have added intelligence to textiles and created
âsmartâ clothes.
Smart textiles can sense and react to environmental
conditions or stimuli, e.g., from mechanical, thermal,
chemical, electrical, or magnetic sources (Lam Po
Tang and Stylios 2006). Such textiles find uses in many
applications ranging from military and security to
personalized healthcare, hygiene, and entertainment.
Smart textiles may be termed ââpassiveââ or ââactive.ââ A
passive smart textile monitors the wearerâs physiology
or the environment, e.g., a shirt with in-built
thermistors to log body temperature over time. If
actuators are integrated, the textile becomes an active,
smart textile as it may respond to a particular stimulus,
e.g., the temperature-aware shirt may automatically
roll up the sleeves when body temperature rises.
The fundamental components in any smart textile
are sensors and actuators. Interconnections, power
supply, and a control unit are also needed to complete
the system. All these components must be integrated
into textiles while still retaining the usual
tactile, flexible, and comfortable properties that we
expect from a textile. Adding new functionalities to
textiles while still maintaining the look and feel of the
fabric is where nanotechnology has a huge impact on
the textile industry. This article describes current developments
in materials for smart nanotextiles and
some of the many applications where these innovative
textiles are of great benefit
Towards Stable Electrochemical Sensing for Wearable Wound Monitoring
Wearable biosensing has the tremendous advantage of providing point-of-care diagnosis and convenient therapy. In this research, methods to stabilize the electrochemical sensing response from detection of target biomolecules, Uric Acid (UA) and Xanthine, closely linked to wound healing, have been investigated. Different kinds of materials have been explored to address such detection from a wearable, healing platform. Electrochemical sensing modalities have been implemented in the detection of purine metabolites, UA and Xanthine, in the physiologically relevant ranges of the respective biomarkers. A correlation can be drawn between the concentrations of these bio-analytes and wound severity, thus offering probable quantitative insights on wound healing progression. These insights attempt to contribute in reducing some impacts of the financial structure on the healthcare economy associated with wound-care.
An enzymatic electrochemical sensing system was designed to provide quick response at a cost-effective, miniaturized scale. Robust enzyme immobilization protocols have assisted in preserving enzyme activity to offer stable response under relevant variations of temperature and pH, from normal. Increased hydrophilicity of the sensor surface using corona plasma, has assisted in improving conductivity, thus allowing for increased electroactive functionalization and loading across the substrateâs surface. Superior sensor response was attained from higher loading of nanomaterials (MWCNT/AuNP) and enzymes (UOx/XO) employed in detection.
Potentiometric analyses of the nanomaterial modified enzymatic biosensors were conducted using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) modalities. Under relevant physiological conditions, the biosensor was noted to offer a variation in response between 10 % and 30 % within a week. Stable, reproducible results were obtained from repeated use of the biosensor over multiple days, also offering promise for continuous monitoring. Shelf life of the biosensor was noted to be more than two days with response retained by about 80 % thereafter. Secondary analyses have been performed utilizing the enzymatic biosensor to explore the feasibility of target biomarker detection from clinical extracts of different biofluids for wound monitoring. Biosensor response evaluation from the extracts of human wound exudate, and those obtained from perilesional and healthy skin, provided an average recovery between 107 % and 110 % with a deviation within (+/-) 6 %. Gradual decrease in response (10-20 %) was noted in detection from extracts further away from injury site. Increased accumulation of biofluids on the sensor surface was studied to explore sensor response stability as a function of sample volume. With a broad linear range of detection (0.1 nM â 7.3 mM) and detection limits lower than the physiological concentrations, this study has assessed the viability of stable wound monitoring under physiologically relevant conditions on a wearable platform
Non-invasive Electronic Biosensor Circuits and Systems
An aging population has lead to increased demand for health-care and an interest in moving health care services from the hospital to the home to reduce the burden on society. One
enabling technology is comfortable monitoring and sensing of bio-signals. Sensors can be embedded in objects that people interact with daily such as a computer, chair, bed, toilet, car, telephone or any portable personal electronic device. Moreover, the relatively recent and wide availability of microelectronics that provide the capabilities of embedded software, open access wireless protocols and long battery life has led many research groups to develop wearable, wireless bio-sensor systems that are worn on the body and integrated into clothing. These systems are capable of interaction with other devices that are nowadays commonly in our possession such as a mobile phone, laptop, PDA or smart multifunctional MP3 player. The development of systems for wireless bio-medical long term monitoring is leading to personal monitoring, not just for medical reasons, but also for enhancing personal awareness and monitoring self-performance, as with sports-monitoring for athletes. These developments also provide a foundation for the Brain Computer Interface (BCI) that aims to directly monitor brain signals in order to control or manipulate external objects. This provides a new communication channel to the brain that does not require activation of muscles and nerves. This innovative and exciting research field is in need of reliable and easy to use long term recording systems (EEG).
In particular we highlight the development and broad applications of our own circuits for wearable bio-potential sensor systems enabled by the use of an amplifier circuit with sufficiently high impedance to allow the use of passive dry electrodes which overcome the significant barrier of gel based contacts
Evaluation of a Behind-the-Ear ECG Device for Smartphone based Integrated Multiple Smart Sensor System in Health Applications
In this paper, we present a wireless Multiple Smart Sensor System (MSSS) in conjunction with a smartphone to enable an unobtrusive monitoring of electrocardiogram (ear-lead ECG) integrated with multiple sensor system which includes core body temperature and blood oxygen saturation (SpO2) for ambulatory patients. The proposed behind-the-ear device makes the system desirable to measure ECG data: technically less complex, physically attached to non-hair regions, hence more suitable for long term use, and user friendly as no need to undress the top garment. The proposed smart sensor device is similar to the hearing aid device and is wirelessly connected to a smartphone for physiological data transmission and displaying. This device not only gives access to the core temperature and ECG from the ear, but also the device can be controlled (removed and reapplied) by the patient at any time, thus increasing the usability of personal healthcare applications. A number of combination ECG electrodes, which are based on the area of the electrode and dry/non-dry nature of the surface of the electrodes are tested at various locations near behind the ear. The best ECG electrode is then chosen based on the Signal-to-Noise Ratio (SNR) of the measured ECG signals. These electrodes showed acceptable SNR ratio of ~20 db, which is comparable with existing tradition ECG electrodes. The developed ECG electrode systems is then integrated with commercially available PPG sensor (Amperor pulse oximeter) and core body temperature sensor (MLX90614) using a specialized micro controller (Arduino UNO) and the results monitored using a newly developed smartphone (android) application
Conception, development and evaluation of polymer-based screen-printed textile electrodes for biopotential monitoring
Wearable technologies represent the new frontier of vital signs monitoring in different
applications, from fitness to health. With the progressive miniaturization of the electronic
components, enabling the implementation of portable and hand-held acquisition and recording
devices, the research focus has shifted toward the development of effective and unobtrusive
textile electrodes. This work deals with the study, development and characterization of
organic-polymer-based electrodes for biopotentials.
After an overview of the main materials and fabrication technologies presented so far in
the scientific literature, the possibility to use these electrodes as an alternative to the Ag/AgCl
disposable gelled electrodes usually adopted in clinical practice was tested. For this purpose,
several textile electrode realization techniques were studied and optimized, in order to create
electrodes with adequate features to detect two fundamental physiological signals: the electrocardiogram
(ECG) and the electromyogram (EMG). The electrodes were obtained by depositing
on the fabric the organic bio-compatible polymer poly(3,4-ethylenedioxythiophene)
doped with poly(4-styrenesulfonate) (PEDOT:PSS) with three deposition procedures: dipcoating,
ink-jet printing and screen printing. The physical\u2013chemical properties of the polymer
solution were varied for each procedure to obtain an optimal and reproducible result. For
what concerns the ECG signal, the research activity focused on screen-printed textile electrodes
and their performance was first assessed by benchtop measurements and then by
human trials. The first tests demonstrated that, by adding solid or liquid electrolytes the
electrodes, the largest part of the characteristics required by the ANSI/AAMI EC12:2000
standard for gelled ECG electrodes can be achieved. Tests performed in different conditions
showed that the skin contact impedance and the ECG morphological features are highly
similar to those obtainable with disposable gelled Ag/AgCl electrodes (\u3c1 > 0.99). A trial
with ten subjects revealed also the capability of the proposed electrodes to accurately capture
with clinical instruments an ECG morphology with performance comparable to off-the-shelf
disposable electrodes. Furthermore, the proposed textile electrodes preserve their electrical
properties and functionality even after several mild washing cycles, while they suffered
physical stretching.
Similar tests were performed on screen-printed textile electrodes fabricated in two different
sizes to test them as EMG sensors, with and without electrolytes. After a series of
controlled acquisitions performed by electro-stimulating the muscles in order to analyze the
waveform morphologu of the M-wave, the statistical analysis showed a high similarity in
terms of rms of the noise and electrode-skin impedance between conventional and textile
electrodes with the addition of solid hydrogel and saline solution. Furthermore, the M-wave
recorded on the tibialis anterior muscle during the stimulation of the peroneal nerve was
comparatively analyzed between conventional and textile electrodes. The comparison provided
an R2 value higher than 97% in all measurement conditions. These results opened their
use in smart garments for real application scenarios and for this purpose were developed a
couple of smart shirts able to detect the EGC and the EMG signal. The results indicated that
this approach could be adopted in the future for the development of smart garments able to
comfortably detect physiological signals
Development and Characterization of Ear-EEG for Real-Life Brain-Monitoring
Functional brain monitoring methods for neuroscience and medical diagnostics have until recently been limited to laboratory settings. However, there is a great potential for studying the human brain in the everyday life, with measurements performed in more realistic real-life settings. Electroencephalography (EEG) can be measured in real-life using wearable EEG equipment. Current wearable EEG devices are typically based on scalp electrodes, causing the devices to be visible and often uncomfortable to wear for long-term recordings. Ear-EEG is a method where EEG is recorded from electrodes placed in the ear. The Ear-EEG supports non-invasive long-term recordings of EEG in real-life in a discreet way. This Ph.D. project concerns the characterization and development of ear-EEG for real-life brain-monitoring. This was addressed through characterization of physiological artifacts in real-life settings, development and characterization of dry-contact electrodes for real-life ear-EEG acquisition, measurements of ear-EEG in real-life, and development of a method for mapping cortical sources to the ear. Characterization of physiological artifacts showed a similar artifact level for recordings from ear electrodes and temporal lobe scalp electrodes. Dry-contact electrodes and flexible earpieces were developed to increase the comfort and user-friendliness of the ear-EEG. In addition, electronic instrumentation was developed to allow implementation in a hearing-aid-sized ear-EEG device. Ear-EEG measurements performed in real-life settings with the dry-contact electrodes, were comparable to temporal lobe scalp EEG, when referenced to a Cz scalp electrode. However, the recordings showed that further development of the earpieces and electrodes are needed to obtain a satisfying recording quality, when the reference is located close to or in the ear. Mapping of the electric fields from well-defined cortical sources to the ear, showed good agreement with previous ear-EEG studies and has the potential to provide valuable information for future development of the ear-EEG method. The Ph.D. project showed that ear-EEG measurements can be performed in real-life, with dry-contact electrodes. The brain processes studied, were established with comparable clarity on recordings from temporal lobe scalp and ear electrodes. With further development of the earpieces, electrodes, and electronic instrumentation, it appears to be realistic to implement ear-EEG into unobtrusive and user-friendly devices for monitoring of human brain processes in real-life
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