Wearable Biomonitoring Research Articles

Hierarchical carbon nanotube-decorated polyacrylonitrile smart textiles for wearable biomonitoring

Respiration monitoring enables continuous assessment of physiological status and potential diseases. We reported a polyacrylonitrile/carbon nanotubes/latex composite membrane (PCM) capable of converting exhalation into a distinct current signal for respiratory rate and depth detection. The latex encapsulation design of respiratory sensor screens moist and thermal fluctuation of respiration and enables an accurate and reliable monitoring of exhaled gas flow. By modulating the compositional ratio, topological characters of interdigital electrode and aperture area, a rapid response time of 192 ms and recovery time of 104 ms, together with great fidelity and reliability were attained for discriminating breathing depth and rate. Combining with machine learning, versatile breathing patterns can be effectively discerned, achieving effective prognosis of respiratory diseases like diabetes, wheezing and obstructive sleep apnoea syndrome. This work endows a low-cost, efficient and stable route for sustainable wearable physiological assessment and disease recognition.

Current Trends in the Development of Electrochemical Biosensor for Detecting Analytes from Sweat.

The need for wearable bioelectronics continues to grow, and this technology might significantly alter the medical field. In order to diagnose and treat a patient, conventional medicine takes a "reactive" approach and waits for symptoms to appear first. Therefore, it is preferable to progress toward continuous non-invasive wearable biomonitoring, a preventative strategy that may assist individuals in diagnosing or treating illnesses at the earliest stages, sometimes before any outward symptoms have appeared. Wearable physiological sensors, such as the Apple Watch and FitBit, have arrived on the market as a result of technology advances and have quickly become commonplace. However, few devices currently exist that can report directly on these biomarkers of relevance. This is mostly due to the challenges involved in real-time fluid sampling and generating correct readouts utilising extremely selective and sensitive sensors. Sweat is an excretory fluid that is only allowed to be used in order to reduce invasiveness, but this restriction places additional strain on sensors owing to the diluted concentration of the relevant biomarkers and the changes in pH, salinity, and other biophysical parameters that directly influence the read-out of real-time biosensors. Sweat is favoured amid slightly invasive biofluids due to its low concentration of interfering chemicals and the fact that it may be collected without touching the mucosal layers. This review offers a concise outline of the latest advances in sweat-based wearable sensors, their promise in healthcare monitoring, and the problems faced in analysis based on sweat.

Stretchable fiber strain sensors for wearable biomonitoring.

Stretchable fiber strain sensors for wearable biomonitoring.

Degradable silk fibroin based piezoresistive sensor for wearable biomonitoring

Degradable wearable electronics are attracting increasing attention to weaken or eliminate the negative effect of waste e-wastes and promote the development of medical implants without secondary post-treatment. Although various degradable materials have been explored for wearable electronics, the development of degradable wearable electronics with integrated characteristics of highly sensing performances and low-cost manufacture remains challenging. Herein, we developed a facile, low-cost, and environmentally friendly approach to fabricate a biocompatible and degradable silk fibroin based wearable electronics (SFWE) for on-body monitoring. A combination of rose petal templating and hollow carbon nanospheres endows as-fabricated SFWE with good sensitivity (5.63 kPa−1), a fast response time (147 ms), and stable durability (15,000 cycles). The degradable phenomenon has been observed in the solution of 1 M NaOH, confirming that silk fibroin based wearable electronics possess degradable property. Furthermore, the as-fabricated SFWE have been demonstrated that have abilities to monitor knuckle bending, muscle movement, and facial expression. This work offers an ecologically-benign and cost-effective approach to fabricate high-performance wearable electronics.

Hierarchical piezoelectric composite film for self-powered moisture detection and wearable biomonitoring

Moisture detection plays a crucial role in physiological monitoring and wearable electronics. Nevertheless, most of the humidity sensors were restricted by the power supply, hindering their applicability in internet of things and mobile healthcare. Herein, we reported a hierarchical piezoelectric composite film for active humidity detection and wearable biomonitoring. The as-electrospun piezoelectric transducing textile consists of samarium-modified lead magnesium niobate lead titanate piezoceramic fillers and polyvinylidene fluoride matrix, while the spin coated polyimide film serves as the humidity sensitive layer. By tuning the thickness ratio between transducing layer and the humidity sensing layer as well as the porosity of the electrode, an optimal moisture-sensing performance was accomplished with a high response of ∼500% and rapid response/recovery time of 23 s/31 s. Furthermore, a theoretical modeling of active humidity sensing mechanism was established by combining thermodynamic derivation and finite element calculation.

Sensing-transducing coupled piezoelectric textiles for self-powered humidity detection and wearable biomonitoring.

The performance of chemical sensors is dominated by the perception of the target molecules via sensitive materials and the conduction of sensing signals through transducers. However, sensing and transduction are spatially and temporally independent in most chemical sensors, which poses a challenge for device miniaturization and integration. Herein, we proposed a sensing-transducing coupled strategy by embedding the high piezoresponse Sm-PMN-PT ceramic (d33 = ∼1500 pC N-1) into a moisture-sensitive polyetherimide (PEI) polymer matrix via electrospinning to conjugate the humidity perception and signal transduction synchronously and sympatrically. Through phase-field simulation and experimental characterization, we reveal the principle of design of the composition and topological structure of sensing-transducing coupled piezoelectric (STP) textiles in order to modulate the recognition, conversion, and sensitive component utilization ratio of the prepared active humidity sensors, achieving high sensitivity (0.9%/RH%) and fast response (20 s) toward ambient moisture. The prepared STP textile can be worn on the human body to realize emotion recognition, exercise status monitoring, and physiological stress identification. This work offers unprecedented insights into the coupling mechanism between chemisorption-related interfacial state and energy conversion efficiency and opens up a new paradigm for developing autonomous, multifunctional and highly sensitive flexible chemical sensors.

Biodegradable cotton fiber-based piezoresistive textiles for wearable biomonitoring

Electronic textiles are fundamentally changing the way we live. However, the inability to effectively recycle them is a considerable burden to the environment. In this study, we developed a cotton fiber-based piezoresistive textile (CF p-textile) for biomonitoring which is biocompatible, biodegradable, and environmentally friendly. These CF p-textiles were fabricated using a scalable dip-coating method to adhere MXene flakes to porous cotton cellulose fibers. The adhesion is made stronger by strong hydrogen bonding between MXene flakes and hierarchically porous cotton cellulose fibers. This cotton-fiber system provides a high sensitivity of 17.73 kPa−1 in a wide pressure range (100 Pa–30 kPa), a 2 Pa subtle pressure detection limit, fast response/recovery time (80/40 ms), and good cycle stability (over 5, 000 cycles). With its compelling sensing performance, the CF p-textile can detect various human biomechanical activities, including pulsation, muscle movement, and swallowing, while still being comfortable to wear. Moreover, the cotton cellulose is decomposed into low-molecular weight cellulose or glucose as a result of the 1,4-glycosidic bond breakage when exposed to acid or during natural degradation, which allows the electronic textile to be biodegradable. This work offers an ecologically-benign, cost-effective and facile approach to fabricating high-performance wearable bioelectronics.

Self-powered multifunctional flexible sensor for wearable biomonitoring

Wearable sensors advance toward the goal of multifunction and integration. Most previous researches focus on the pressure or temperature sensibility, while moisture perception enabling proximity sense and noncontact control of soft robotic and human-machine interfacing still remains a challenge. Herein, we reported a flexible self-powered multifunctional sensor (FSMS) based on fluoropolymer composites for simultaneously and actively detecting the moist, thermal and pressure stimuli. The inclusion of lithium chloride (LiCl) and polyvinyl alcohol (PVA) endows the fluoropolymer composites with excellent humidity sensing capabilities of low hysteresis (2.1%) and short response time (9 s). The as-prepared FSMS can be easily worn on versatile places of human body for wearable biomonitoring of arterial pulse and respiration as well as human-machine interaction. A moist-thermal coupling (MTC) mode is invented to boost the sensitivity for respiratory monitoring and noncontact human-machine interaction. This work opens up a new paradigm to develop multifunctional biomonitoring devices and artificial skin for next-generation wearable electronics.

Bioinspired acoustic textiles with nanoscale vibrations for wearable biomonitoring

The smart textile research community is advancing rapidly with the aim of changing the way we wear clothes in the near future. An eardrum-inspired acoustic textile was recently developed that can function as a sensitive audible microphone. The acoustic textile is woven from yarns with a high Young's modulus and thermal drawing composite piezoelectric fibers that can concentrate mechanical stress in the piezoelectric composite layer during the heat drawing process, endowing the fiber with high sensitivity. The acoustic textile can convert even very slight 10⁻⁷ atmospheric pressure waves at audible frequencies into mechanical vibrations with nanometer amplitudes, which further induce the electrical signals through the fibers to detect the direction of sound pulses, broadcast human speech, and capture heartbeats, making it suitable as a wearable platform for long-term biomonitoring.

MXene‐Sponge Based High‐Performance Piezoresistive Sensor for Wearable Biomonitoring and Real‐Time Tactile Sensing (Small Methods 2/2022)

Flexible Piezoresistive Pressure Sensor In article number 2101051, Ye, Xie, Su, Chen and co-workers were inspired by Helium embrittlement during nuclear fusion processes, to utilize Helium plasma irradiation to yield a nano-fuzz-shaped molybdenum electrode for a flexible piezoresistive pressure sensor, which was demonstrated to measure human radial pulse, detect the tapping, stamping, and perform object identification, revealing great feasibility in wearable biomonitoring and healthcare assessment.

Self-Powered Multifunctional Flexible Sensor for Wearable Biomonitoring

Self-Powered Multifunctional Flexible Sensor for Wearable Biomonitoring

MXene-Sponge Based High-Performance Piezoresistive Sensor for Wearable Biomonitoring and Real-Time Tactile Sensing.

Electrode microfabrication technologies such as lithography and deposition have been widely applied in wearable electronics to boost interfacial coupling efficiency and device performance. However, a majority of these approaches are restricted by expensive and complicated processing techniques, as well as waste discharge. Here, helium plasma irradiation is employed to yield a molybdenum microstructured electrode, which is constructed into a flexible piezoresistive pressure sensor based on a Ti3 C2 Tx nanosheet-immersed polyurethane sponge. This electrode engineering strategy enables the smooth transition between sponge deformation and MXene interlamellar displacement, giving rise to high sensitivity (1.52kPa-1 ) and good linearity (r2 =0.9985) in a wide sensing range (0-100kPa) with a response time of 226ms for pressure detection. In addition, both the experimental characterization and finite element simulation confirm that the hierarchical structures modulated by pore size, plasma bias, and MXene concentration play a crucial role in improving the sensing performance. Furthermore, the as-developed flexible pressure sensor is demonstrated to measure human radial pulse, detect finger tapping, foot stomping, and perform object identification, revealing great feasibility in wearable biomonitoring and health assessment.

Piezoelectric fiber composites with polydopamine interfacial layer for self-powered wearable biomonitoring

Doping polymers with ceramic nanofillers is a widely-adopted routine for developing high-performance nanocomposites. However, improving the interaction between the nanofillers and the polymer matrix for an enhanced composite performance remains highly desired in the community. Herein, we systematically investigated the barium titanate doped polyvinylidene fluoride (BTO/PVDF) piezoelectric nanocomposites in a fiber form through comprehensive phase-field simulation and detailed experimental characterization. Both experimental and theoretical results indicated that the introduction of 2.15 vol% polydopamine (PDA) coating on the BTO nanoparticles could remarkably promote the local all-trans conformation and modulus match at the nanofillers-polymer interface, giving rise to the maximum piezoelectric charge coefficient and piezoelectric voltage coefficient as well as mechanical stiffness. To demonstrate the effectiveness of the PDA modification, a polydopamine modified nonwoven piezoelectric (PMNP) textile was constructed based on the composite fiber, which showed outstanding sensitivity and long-term stability for wearable biomonitoring, including limb motion detection, facial expression identification, respiratory monitoring, and human-machine interfacing. This work endows insight into the fundamental mechanism of the interfacial coupling effect in polymer composites for the development of high-performance wearable textile bioelectronics. • Polydopamine modified nonwoven piezoelectric (PMNP) textile was developed. • The mechanism was studied via phase-field simulation and detailed characterization. • 2.15 vol% PDA coating maximizes the piezoelectric coefficient and β phase content. • Facial emotion identification and human-machine interaction was enabled by PMNPs.

Possibilities to integrate wearable biomonitoring sensors into adaptive lighting systems

There are two trends in modern lighting: the first one is lighting intelligence and adaptability, and the other is an orientation on the biological effects of light on the human body. This article analyzes the possibilities for further development of adaptive lighting systems from human biomonitoring data integration point of view. A review of wearable medical devices, which in the future could work as sensors of an adaptive lighting system, is presented.

A Wireless Textile-Based Sensor System for Self-Powered Personalized Health Care

Summary Internet-connected clothing/textiles is a promising but underexplored option for future personalized health care. Here, we report a textile-based sensor (TS) system with art design for wearable biomonitoring and interacting over the Internet. The TS is capable of delivering a sensitivity up to 3.88 V/kPa for ambient tiny pressure sensing. Made of durable materials, the TS exhibits remarkable robustness after more than 80,000 cycles of continuous operation. A wireless biomonitoring system (WBS) has been developed for timely processing of the acquired human pulse wave signals, wirelessly transmitting and displaying the patient’s health data via an APP interface onto a smartphone. The WBS was used to effectively diagnose obstructive sleep apnea-hypopnea syndrome during a whole night of sleep even with body movements. The textile-based wireless biomonitoring system represents a solid step toward constructing a body area network for personalized health care in the era of the Internet of Things.

Drop-on-demand high-speed 3D printing of flexible milled carbon fiber/silicone composite sensors for wearable biomonitoring devices

Three-dimensionally (3D) printed flexible piezoresistive composite sensors have provided valuable solutions for the personalized therapeutic development due to their promising capability in biomonitoring applications. Silicone rubber (SR) matrix is an important candidate to enable flexibility to the 3D printed devices. However, 3D printing of silicone inks blended with conductive fillers is limited due to the high viscosity, long curing time, and high percolation threshold. In the present study, a novel high-speed material jetting (MJ) 3D printing of high-viscosity conductive inks based on the mixture of a UV crosslinkable silicone rubber and milled carbon fibers (MCF) is demonstrated. The MCF content was optimized for printability, UV curability, and electrical conductivity. The sensors (with 30 wt. % MCF content) show high flexibility and foldability as well as a high resistance sensitivity to sever bending tests. The stretchability of 3D printed sensors was further improved by sandwiching the MCF/SR sensing layer between the SR layers. The electromechanical evaluation of the sandwiched MCF/SR sensors (S-MCF/SR) confirmed the high piezoresistive sensitivity of sensors (gauge factor in order of ∼400). Finally, the 3D printed sensors were employed for monitoring human joint motions to demonstrate the potential application in monitoring biosignals.

Soft Bioelectronic Stickers: Selection and Evaluation of Skin-Interfacing Electrodes.

Surface biopotentials collected from the human epidermis contain important information about human physiology, such as muscular, heart, and brain activities. However, commercially available wearable biomonitoring devices are generally composed of rigid hardware incompatible with the mechanical compliance of soft human tissues. Thin-film stretchable e-skin circuits that can interface the human skin represent an excellent alternative for long-term wearable biomonitoring. Here, a series of soft and stretchable electrodes are evaluated for their applicability in biopotential sensing. This includes conductive composites made of polydimethylsiloxane (PDMS) as a base substrate and conductive particles, i.e., carbon (cPDMS), silver (AgPDMS), anisotropic z-axis conductors made with silver-coated nickel particles (zPDMS), as well as a combination of a conductive tough hydrogel with PDMS, and finally ultrathin tattoo-like adhesive poly(vinyl alcohol)-coated films with stretchable biphasic Ag-EGaIn electrodes. These electrodes are compared between themselves and against the gold-standard Ag/AgCl and stainless steel electrodes, in order to assess relative performance in signal-to-noise ratio (SNR) during electrocardiography, and electrode-skin impedance for a range of frequencies. Results show a direct relation between conformity of the electrode-skin interface and the SNR value. An all-integrated biomonitoring patch with embedded processing and communication electronics, hydrogel electrodes, and a multilayer liquid metal circuit is presented for electromyography.

Continuous Mobile Wearable Bio-Monitoring of Newly Diagnosed Multiple Myeloma Patients Undergoing Initial Chemotherapy

IntroductionThe current standard to assess chemotherapy tolerability relies on patient self-reporting. However, as the sole mechanism of managing symptom burden, this may be inconsistent and fraught with bias. Mobile wearable health devices have the ability to monitor and aggregate objective activity and sleep data over long periods of time, but have not been systematically used in the oncology clinic. The aim of the study was to assess whether the use of mobile wearable technology establishes patterns of “sleep” and “wake” states in newly diagnosed Multiple Myeloma (NDMM) patients receiving therapy, and whether these patterns differ over time.MethodsPatients presenting to the myeloma clinic at Memorial Sloan Kettering Cancer Center (MSKCC) with a new diagnosis of Multiple Myeloma and smart phone or tablet (iOS or Android) compatible with the Garmin Vivofit device were offered to participate in a mobile wearable bio-monitoring study. All eligible participants were required to receive primary chemotherapy treatment at a MSKCC facility. Treatment was determined by physician. NDMM patients were assigned to one of two cohorts (20 in each; Cohort A - patients <65 years; Cohort B - patients ≥ 65 years). Patients were given Garmin Vivofit devices and asked to download a Garmin Vivofit application and Medidata electronic patient reported outcome (ePRO) application on their phone or tablet. Patients were bio-monitored for physical activity and sleep during baseline period (1-7 days prior to chemotherapy initiation) and continuously up to 6 cycles of chemotherapy. Additionally, patients completed mobile ePRO questionnaires [(EORTC - QLQC30 and MY20) and brief pain inventory scales (BPI)] using the Medidata application at baseline and after each induction cycle. Activity, sleep data, and completed ePRO questionnaire data were automatically synced or transferred to Medidata Rave database through Medidata Sensorlink technology. In this abstract, we report initial results on prospective collection of activity measurements. Additional data from the health-related quality of life questionnaires and clinical outcomes will be presented at later date.ResultsBetween February 2017-March 2018, 37 patients (19 males and 18 females) enrolled onto the study, with 20 in cohort A and 17 in cohort B. The mean age was 55 years (range 41-64) for cohort A and 72 years (range 65-82) for cohort B. Treatment regimens included Carfilzomib/Revlimid/Dexamethasone 14(38%), Velcade/Revlimid/Dexamethasone 10(27%), Daratumumab/Carfilzomib Revlimid/Dexamethasone, 7(19%), Cyclophosphamide/Velcade/Dexamethasone 3(8%), Revlimid/Dexamethasone 2(5%), and Velcade/Revlimid/Dexamethasone-Lite 1(3%). Twenty-four patients have completed the trial, and 7 remain active. Six patients came off-study due to the following reasons: lost devices (n=4), intolerable rash during cycle 3 (n=1), and incompletion of baseline activity (n=1). Three patients were excluded for incomplete data sets with no baseline data collection at the time of analysis. Fifteen patients were available for data review including 10 in cohort A and 5 in cohort B.Mean activity for cohort A was 6,437 steps/24 hr period (1,002 - 12,754) versus for cohort B was 3,218.37 steps/24 hr period (387 - 6,155) (p <0.05). In comparing pre- and post-therapy, overall mean activity for cohort A increased from 5,995 to 6,513 steps/24 hr, 8.6% increase (p=0.78), and for cohort B mean activity increased from 2,249 to 3,420 steps/24 hr, a 52% increase (p=0.2140). We assessed short term effects therapy initiation had on activity for NDMM patients by comparing percent changes in activity (steps/24 hrs) from baseline period to cycle 1 period. We found 3 patients had a >100% increase, 1 patient had 50-100% increase, and 11 patients had within +/- 50% change in activity from baseline.ConclusionElectronic mobile wearable device monitoring in symptomatic NDMM patients may be a useful tool to assess a patient's overall wellness and health as they are receiving chemotherapy. For three patients, we were able to capture a dramatic increase in activity after initiation of treatment. Overall activity in the elderly NDMM patients is decreased compared to younger patients. Mobile wearable monitoring may be an even more useful strategy for tracking elderly and unfit patients that are more prone to side effects, where the balance of response versus quality of life is paramount. DisclosuresMailankody:Physician Education Resource: Honoraria; Janssen: Research Funding; Takeda: Research Funding; Juno: Research Funding. Hassoun:Oncopeptides AB: Research Funding. Lesokhin:Squibb: Consultancy, Honoraria; Serametrix, inc.: Patents & Royalties: Royalties; Janssen: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Takeda: Consultancy, Honoraria. Smith:Celgene: Consultancy, Patents & Royalties: CAR T cell therapies for MM, Research Funding. Shah:Amgen: Research Funding; Janssen: Research Funding. Landgren:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Research Funding; Pfizer: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy. Korde:Amgen: Research Funding.

Wearable Biomonitoring Platform for the Assessment of Stress and its Impact on Cognitive Performance of Firefighters: An Experimental Study.

Background:Stress is a complex process with an impact on health and performance. The use of wearable sensor-based monitoring systems offers interesting opportunities for advanced health care solutions for stress analysis. Considering the stressful nature of firefighting and its importance for the community’s safety, this study was conducted for firefighters.Objectives:A biomonitoring platform was designed, integrating different biomedical systems to enable the acquisition of real time Electrocardiogram (ECG), computation of linear Heart Rate Variability (HRV) features and collection of perceived stress levels. This platform was tested using an experimental protocol, designed to understand the effect of stress on firefighter’s cognitive performance, and whether this effect is related to the autonomic response to stress.Method:The Trier Social Stress Test (TSST) was used as a testing platform along with a 2-Choice Reaction Time Task. Linear HRV features from the participants were acquired using an wearable ECG. Self-reports were used to assess perceived stress levels.Results:The TSST produced significant changes in some HRV parameters (AVNN, SDNN and LF/HF) and subjective measures of stress, which recovered after the stress task. Although these short-term changes in HRV showed a tendency to normalize, an impairment on cognitive performance was found after performing the stress event.Conclusion:Current findings suggested that stress compromised cognitive performance and caused a measurable change in autonomic balance. Our wearable biomonitoring platform proved to be a useful tool for stress assessment and quantification. Future studies will implement this biomonitoring platform for the analysis of stress in ecological settings.

Biomonitoring Laboratory Oriented to Software Applications Development

Abstract This paper presents a project-oriented laboratory. It is intended to provide an educational and research environment that stimulates innovative solutions in the growing field of Bioengineering. The authors took the advantages of the emerging technology and the increasing popularity of wearable biomonitoring devices, to teach students the key elements regarding the application of Information Technology in health monitoring. The students were involved in a complex project, along which they gain basic knowledge about the software development for biomonitoring, and apply it to effectively develop common structures and software applications. There are presented the stages of the laboratory work, with illustrations of the applications implementation at different levels of the hierarchy, starting from collecting data from the biomonitoring device, and finalizing with the data visualization by the end-user.