Open-source FlexNIRS: A low-cost, wireless and wearable cerebral health tracker.

Currently, there is great interest in making neuroimaging widely accessible and thus expanding the sampling population for better understanding and preventing diseases. The use of wearable health devices has skyrocketed in recent years, allowing continuous assessment of physiological parameters in patients and research cohorts. While most health wearables monitor the heart, lungs and skeletal muscles, devices targeting the brain are currently lacking. To promote brain health in the general population, we developed a novel, low-cost wireless cerebral oximeter called FlexNIRS. The device has 4 LEDs and 3 photodiode detectors arranged in a symmetric geometry, which allows for a self-calibrated multi-distance method to recover cerebral hemoglobin oxygenation (SO2) at a rate of 100 Hz. The device is powered by a rechargeable battery and uses Bluetooth Low Energy (BLE) for wireless communication. We developed an Android application for portable data collection and real-time analysis and display. Characterization tests in phantoms and human participants show very low noise (noise-equivalent power <70 fW/√Hz) and robustness of SO2 quantification in vivo. The estimated cost is on the order of $50/unit for 1000 units, and our goal is to share the device with the research community following an open-source model. The low cost, ease-of-use, smart-phone readiness, accurate SO2 quantification, real time data quality feedback, and long battery life make prolonged monitoring feasible in low resource settings, including typically medically underserved communities, and enable new community and telehealth applications.

Pricing through health apps generated data-Digital dividend as a game changer: Discrete choice experiment.

OBJECTIVES: The objective of this paper is to study under which circumstances wearable and health app users would accept a compensation payment, namely a digital dividend, to share their self-tracked health data. METHODS: We conducted a discrete choice experiment alternative, a separated adaptive dual response. We chose this approach to reduce extreme response behavior, considering the emotionally-charged topic of health data sales, and to measure willingness to accept. Previous experiments in lab settings led to demands for high monetary compensation. After a first online survey and two pre-studies, we validated four attributes for the final online study: monthly bonus payment, stakeholder handling the data (e.g., health insurer, pharmaceutical or medical device companies, universities), type of data, and data sales to third parties. We used a random utility framework to evaluate individual choice preferences. To test the expected prices of the main study for robustness, we assigned respondents randomly to one of two identical questionnaires with varying price ranges. RESULTS: Over a period of three weeks, 842 respondents participated in the main survey, and 272 respondents participated in the second survey. The participants considered transparency about data processing and no further data sales to third parties as very important to the decision to share data with different stakeholders, as well as adequate monetary compensation. Price expectations resulting from the experiment were high; pharmaceutical and medical device companies would have to pay an average digital dividend of 237.30€/month for patient generated health data of all types. We also observed an anchor effect, which means that people formed price expectations during the process and not ex ante. We found a bimodal distribution between relatively low price expectations and relatively high price expectations, which shows that personal data selling is a divisive societal issue. However, the results indicate that a digital dividend could be an accepted economic incentive system to gather large-scale, self-tracked data for research and development purposes. After the COVID-19 crisis, price expectations might change due to public sensitization to the need for big data research on patient generated health data. CONCLUSION: A continuing success of existing data donation models is highly unlikely. The health care sector needs to develop transparency and trust in data processing. An adequate digital dividend could be an effective long-term measure to convince a diverse and large group of people to share high-quality, continuous data for research purposes.

Financial incentives and wearable activity monitors to increase ambulation after cystectomy: A randomized controlled trial.

OBJECTIVES: Financial incentive programs are effective in increasing physical activity for overweight, ambulatory adults. We sought to determine the potential effect size and direction of financial incentives on ambulation after radical cystectomy. MATERIALS AND METHODS: We performed a pilot randomized controlled trial of daily financial incentives to meet postoperative step goals among adults with Eastern Cooperative Oncology Group performance status ≤2 who underwent radical cystectomy for bladder cancer at a single center. Step counts were measured over a 3- to 14-day preoperative period and 30-day postoperative period using a wearable activity monitor. Postoperative daily step goals of 10%, 25%, 40%, and 55% of mean preoperative daily step counts were set for postoperative weeks 1 through 4, respectively. The primary outcome was the number of postoperative days on which the step goals were met. Secondary outcomes included the number of daily postoperative steps taken and the length of stay. Participants randomized to the intervention arm received $1.50 for every day the goal was met with a 20% chance of a $100 reward if the step goal was met on >75% of the first 30 postoperative days. Questionnaires assessing self-reported physical activity, disability, and social support were administered preoperatively at 30 days postoperatively. RESULTS: Thirty-three patients were analyzed, 11 in the control and 22 in the intervention arms. There were no statistically significant differences between incentive and control arms for the primary outcome (4.5/30 days vs. 9/30 days, P = 0.53). Results after adjusting for differences in baseline characteristics were similar (RR 1.00, 95% CI 0.24-4.19, P = 1.00). There were also no differences in average daily postoperative steps (median 979 vs. 1191, 95% CI -810 to 1,400, P = 0.59), length of stay (7.5 vs. 7, 95% CI -2.7 to 5.1, P = 0.56), or self-reported measures of disability, activity, and social support. CONCLUSIONS: While this trial was a pilot study and not powered to detect a difference between groups, there was no suggestion of any clinically important impact of this financial incentive on postoperative ambulation. While a fully-powered trial is feasible, given the small range of plausible benefit, such a trial would be unlikely to influence clinical practice.

MOF based flexible, low-cost chemiresistive device as a respiration sensor for sleep apnea diagnosis.

The monitoring of respiratory disorders requires breath sensors that are fast, robust, and convenient to use and can function under real time conditions. A MOF based flexible sensor is reported for the first time for breath sensing applications. The properties of a highly porous HKUST-1 MOF and a conducting MoS2 material have been combined to fabricate an electronic sensor on a flexible paper support for studying sleep apnea problems. Extensive breath sensing experiments have been performed and interestingly the fabricated sensor is efficient in detecting various kinds of breaths such as deep, fast, slow and hydrated breath. The MOF breath sensor shows a fast response time of just ∼0.38 s and excellent stability with no decline in its performance even after a month. A plausible mechanism has been proposed and a smartphone based prototype has been prepared to demonstrate the real time applications of the hybrid device. This work demonstrates great potential for the application of MOFs in healthcare with a special focus on breath sensing and sleep apnea diagnosis.

Comparison of anorectal function measured using wearable digital manometry and a high resolution manometry system.

There is a need for a lower cost manometry system for assessing anorectal function in primary and secondary care settings. We developed an index finger-based system (termed "digital manometry") and tested it in healthy volunteers, patients with chronic constipation, and fecal incontinence. Anorectal pressures were measured in 16 participants with the digital manometry system and a 23-channel high-resolution anorectal manometry system. The results were compared using a Bland-Altman analysis at rest as well as during maximum squeeze and simulated defecation maneuvers. Myoelectric activity of the puborectalis muscle was also quantified simultaneously using the digital manometry system. The limits of agreement between the two methods were -7.1 ± 25.7 mmHg for anal sphincter resting pressure, 0.4 ± 23.0 mmHg for the anal sphincter pressure change during simulated defecation, -37.6 ± 50.9 mmHg for rectal pressure changes during simulated defecation, and -20.6 ± 172.6 mmHg for anal sphincter pressure during the maximum squeeze maneuver. The change in the puborectalis myoelectric activity was proportional to the anal sphincter pressure increment during a maximum squeeze maneuver (slope = 0.6, R2 = 0.4). Digital manometry provided a similar evaluation of anorectal pressures and puborectalis myoelectric activity at an order of magnitude less cost than high-resolution manometry, and with a similar level of patient comfort. Digital Manometry provides a simple, inexpensive, point of service means of assessing anorectal function in patients with chronic constipation and fecal incontinence.

Design of a Low-Cost, Wearable Device for Kinematic Analysis in Physical Therapy Settings.

BACKGROUND: Unsupervised home exercise is a major component of physical therapy (PT). This study proposes an inexpensive, inertial measurement unit-based wearable device to capture kinematic data to facilitate exercise. However, conveying and interpreting kinematic data to non-experts poses a challenge due to the complexity and background knowledge required that most patients lack. OBJECTIVES: The objectives of this study were to identify key user interface and user experience features that would likely improve device adoption and assess participant receptiveness toward the device. METHODS: Fifty participants were recruited to perform nine upper extremity exercises while wearing the device. Prior to exercise, participants completed an orientation of the device, which included examples of software graphics with exercise data. Surveys that measured receptiveness toward the device, software graphics, and ergonomics were given before and after exercise. RESULTS: Participants were highly receptive to the device with 90% of the participants likely to use the device during PT. Participants understood how the simple kinematic data could be used to aid exercise, but the data could be difficult to comprehend with more complex movements. Devices should incorporate wireless sensors and emphasize ease of wear. CONCLUSION: Device-guided home physical rehabilitation can allow for individualized treatment protocols and improve exercise self-efficacy through kinematic analysis. Future studies should implement clinical testing to evaluate the impact a wearable device can have on rehabilitation outcomes.

Health promotion with physiolytics: What is driving people to subscribe in a data-driven health plan.

Data-driven health promotion programs and health plans try to harness the new possibilities of ubiquitous and pervasive physiolytics devices. In this paper we seek to explore what drives people to subscribe to such a data-driven health plan. Our study reveals that the decision to subscribe to a data-driven health plan is strongly influenced by the beliefs of seeing physiolytics as enabler for positive health behavior change and of perceiving health insurances as trustworthy organizations that are capable of securely and righteously manage the data collected by physiolytics.

The impact of IoT security labelling on consumer product choice and willingness to pay.

The Internet of Things (IoT) brings internet connectivity to everyday electronic devices (e.g. security cameras and smart TVs) to improve their functionality and efficiency. However, serious security and privacy concerns have been raised about the IoT which impact upon consumer trust and purchasing. Moreover, devices vary considerably in terms of the security they provide, and it is difficult for consumers to differentiate between more and less secure devices. One proposal to address this is for devices to carry a security label to help consumers navigate the market and know which devices to trust, and to encourage manufacturers to improve security. Using a discrete choice experiment, we estimate the potential impact of such labels on participant's purchase decision making, along with device functionality and price. With the exception of a label that implied weak security, participants were significantly more likely to select a device that carried a label than one that did not. While they were generally willing to pay the most for premium functionality, for two of the labels tested, they were prepared to pay the same for security and functionality. Qualitative responses suggested that participants would use a label to inform purchasing decisions, and that the labels did not generate a false sense of security. Our findings suggest that the use of a security label represents a policy option that could influence behaviour and that should be seriously considered.

Cost-Effective Wearable Indoor Localization and Motion Analysis via the Integration of UWB and IMU.

Wearable indoor localization can now find applications in a wide spectrum of fields, including the care of children and the elderly, sports motion analysis, rehabilitation medicine, robotics navigation, etc. Conventional inertial measurement unit (IMU)-based position estimation and radio signal indoor localization methods based on WiFi, Bluetooth, ultra-wide band (UWB), and radio frequency identification (RFID) all have their limitations regarding cost, accuracy, or usability, and a combination of the techniques has been considered a promising way to improve the accuracy. This investigation aims to provide a cost-effective wearable sensing solution with data fusion algorithms for indoor localization and real-time motion analysis. The main contributions of this investigation are: (1) the design of a wireless, battery-powered, and light-weight wearable sensing device integrating a low-cost UWB module-DWM1000 and micro-electromechanical system (MEMS) IMU-MPU9250 for synchronized measurement; (2) the implementation of a Mahony complementary filter for noise cancellation and attitude calculation, and quaternions for frame rotation to obtain the continuous attitude for displacement estimation; (3) the development of a data fusion model integrating the IMU and UWB data to enhance the measurement accuracy using Kalman-filter-based time-domain iterative compensations; and (4) evaluation of the developed sensor module by comparing it with UWB- and IMU-only solutions. The test results demonstrate that the average error of the integrated module reached 7.58 cm for an arbitrary walking path, which outperformed the IMU- and UWB-only localization solutions. The module could recognize lateral roll rotations during normal walking, which could be potentially used for abnormal gait recognition.

Patient Use of Cardiovascular Devices and Apps: Are We Getting Our Money's Worth?

The evolution of technology makes it likely that a large number of people will invest in and use health-related mobile applications and wearable devices. Yet the question remains: Do these technology-based interventions modify health behavior and improve health…and are we getting our money's worth? The vast majority of studies concerning health-related apps and wearable devices have small sample sizes and short time spans of 6 months or less, so it is not clear if these durations were determined by lack of consistent use over time. Furthermore, many of the most popular applications have not been subjected to randomized trials. Overall, the small demonstrated improvements in outcomes are often associated with professional involvement from clinicians, coaches, or diabetes educators provided in conjunction with use of mobile health (mHealth) platforms. This paper explores the use of mHealth technologies that address cardiovascular disease/prevention (eg, diabetes, diet, physical activity, and associated weight loss) and discusses the lack of adequate evidence to support even minimal patient investment in mobile applications or wearable devices at this time.

Wearable cardioverter-defibrillators in pediatric cardiomyopathy: A cost-utility analysis.

BACKGROUND: Dilated cardiomyopathy (DCM) is the most common cardiomyopathy in children. Patients with severe cardiac dysfunction are thought to be at risk of sudden cardiac arrest (SCA). After diagnosis, a period of medical optimization is recommended before permanent implantable cardioverter-defibrillator (ICD) implantation. Wearable cardioverter-defibrillators (WCDs) provide an option for arrhythmia protection as an outpatient during this optimization. OBJECTIVE: The purpose of this study was to determine the strategy that optimizes cost and survival during medical optimization of a patient with DCM before ICD placement. METHODS: A Markov state transition model was constructed for the 3 clinical approaches to compare costs, clinical outcomes, and quality of life: (1) "Inpatient," (2) "Home-WCD," and (3) "Home-No WCD." Transitional probabilities, costs, and utility metrics were extracted from the existing literature. Cost-effectiveness was assessed comparing each paradigm's incremental cost-effectiveness ratio against a societal willingness-to-pay threshold of $50,000 per quality-adjusted life year. RESULTS: The cost-utility analysis illustrated that Home-WCD met the willingness-to-pay threshold with an incremental cost-effectiveness ratio of $20,103 per quality-adjusted life year and 4 mortalities prevented per 100 patients as compared with Home-No WCD. One-way sensitivity analyses demonstrated that Home-No WCD became the most cost-effective solution when the probability of SCA fell below 0.2% per week, the probability of SCA survival with a WCD fell below 9.8%, or the probability of SCA survival with Home-No WCD quadrupled from base-case assumptions. CONCLUSION: Based on the existing literature probabilities of SCA in pediatric patients with DCM undergoing medical optimization before ICD implantation, sending a patient home with a WCD may be a cost-effective strategy.

Ultra-simple wearable local sweat volume monitoring patch based on swellable hydrogels.

Quantifiably monitoring sweat rate and volume is important to assess the stress level of individuals and/or prevent dehydration, but despite intense research, a convenient, continuous, and low-cost method to monitor sweat rate and total sweat volume loss remains an un-met need. We present here an ultra-simple wearable sensor capable of measuring sweat rate and volume accurately. The device continuously monitors sweat rate by wicking the produced sweat into hydrogels that measurably swell in their physical geometry. The device has been designed as a simple to fabricate, low-cost, disposable patch. This patch exhibits stable and predictable operation over the maximum variable chemistry expected for sweat (pH 4-9 and salinity 0-100 mM NaCl). Preliminary in vivo testing of the patch has been achieved during aerobic exercise, and the sweat rates measured via the patch accurately follow actual sweat rates.

Lessons Learned: Recommendations For Implementing a Longitudinal Study Using Wearable and Environmental Sensors in a Health Care Organization.

Although traditional methods of data collection in naturalistic settings can shed light on constructs of interest to researchers, advances in sensor-based technology allow researchers to capture continuous physiological and behavioral data to provide a more comprehensive understanding of the constructs that are examined in a dynamic health care setting. This study gives examples for implementing technology-facilitated approaches and provides the following recommendations for conducting such longitudinal, sensor-based research, with both environmental and wearable sensors in a health care setting: pilot test sensors and software early and often; build trust with key stakeholders and with potential participants who may be wary of sensor-based data collection and concerned about privacy; generate excitement for novel, new technology during recruitment; monitor incoming sensor data to troubleshoot sensor issues; and consider the logistical constraints of sensor-based research. The study describes how these recommendations were successfully implemented by providing examples from a large-scale, longitudinal, sensor-based study of hospital employees at a large hospital in California. The knowledge gained from this study may be helpful to researchers interested in obtaining dynamic, longitudinal sensor data from both wearable and environmental sensors in a health care setting (eg, a hospital) to obtain a more comprehensive understanding of constructs of interest in an ecologically valid, secure, and efficient way.

Evaluating the Use of Commercially Available Wearable Wristbands to Capture Adolescents' Daily Sleep Duration.

Commercially available wearable devices are marketed as a means of objectively capturing daily sleep easily and inexpensively outside of the laboratory. Two ecological momentary assessment studies-with 120 older adolescents (aged 18-19) and 395 younger adolescents (aged 10-16)-captured nightly self-reported and wearable (Jawbone) recorded sleep duration. Self-reported and wearable recorded daily sleep duration were moderately correlated (r ~ .50), associations which were stronger on weekdays and among young adolescent boys. Older adolescents self-reported sleep duration closely corresponded with estimates from the wearable device, but younger adolescents reported having an hour more of sleep, on average, compared to device estimates. Self-reported, but not wearable-recorded, sleep duration and quality were consistently associated with daily well-being measures. Suggestions for the integration of commercially available wearable devices into future daily research with adolescents are provided.

Effect of V-Go Versus Multiple Daily Injections on Glycemic Control, Insulin Use, and Diabetes Medication Costs Among Individuals with Type 2 Diabetes Mellitus.

BACKGROUND: Coping with discomfort and the uncertainties of daily adjustments are prominent challenges confronting individuals with type 2 diabetes mellitus (T2DM) who require multiple daily injections (MDI) of insulin. For this growing population, wearable, disposable devices capable of delivering consistent and sustained doses of basal-bolus therapy may help to alleviate concerns and improve outcomes. However, studies on the comparative effectiveness of new, innovative delivery systems versus MDI on insulin requirements, glycemic control, and health care costs are sparse. OBJECTIVE: To examine glycemic control, insulin use, and diabetes medication costs for users of the V-Go Wearable Insulin Delivery device compared with MDI insulin therapy among individuals with T2DM in a commercially insured population in the United States. METHODS: This retrospective cohort study queried administrative claims data from the HealthCore Integrated Research Database from July 1, 2011, through July 31, 2017. Cohorts included individuals with T2DM aged 21-80 years either newly initiating V-Go or using MDI for basal/bolus insulin. The date of earliest claim for V-Go prescription fill or for bolus insulin was defined as the index date, depending on the cohort. Previous insulin therapy was required in both cohorts. Baseline hemoglobin A1c (A1c) values were identified during the 6 months before and 15 days after the index date; results closest to 12 months after the index date were selected as follow-up. Insulin use and diabetes medication cost data were examined during the 6 months baseline and the second half of the 1-year follow-up. V-Go and MDI users were 1:1 matched on baseline insulin exposure, A1c level, and other characteristics of interest. Univariate and multivariate tests were used to compare follow-up outcomes. RESULTS: Matched cohorts included 118 well-balanced pairs (mean age: 56 years; mean baseline A1c: 9.2%). During follow-up, both cohorts experienced improvements in glycemic control relative to baseline (% with A1c ≤ 9%, baseline/follow-up: V-Go 49/69, P < 0.001; MDI 50/60, P = 0.046). With similar baseline insulin prescription fills and diabetes medication costs, V-Go users required fewer insulin prescription fills (mean change: -0.8 vs. +1.8 fills, P < 0.001; -17% vs. +38%); had a smaller increase in diabetes medication costs (mean change in 2016 USD: $341 vs. $1,628, P = 0.012; +10% vs. +47%); and a decrease in insulin total daily dose (mean change in insulin units per day: -29.2 vs. +5.8, P < 0.001; -21% vs. +4%), compared with MDI users, during the last 6 months of follow-up. CONCLUSIONS: This study was the first to evaluate clinical and economic outcomes associated with the use of V-Go for up to a 1-year follow-up period. Relative to MDI users, V-Go users had similar glycemic control but lower insulin use and lower diabetes medication costs during follow-up. V-Go therapy may provide an opportunity to improve quality measures more cost-effectively in people with T2DM who require basal-bolus therapy. DISCLOSURES: This study was funded by Valeritas. Nguyen is an employee of Valeritas. Zhou, Grabner, Barron, and Quimbo are employees of HealthCore, which received funding for this study from Valeritas. Raval was an employee of HealthCore at the time the study was conducted. Partial findings from this study were presented at the International Society of Pharmacoeconomics and Outcomes Research 23rd Annual International Meeting; May 19-23, 2018; Baltimore, MD; and the 54th European Association for the Study of Diabetes Annual Meeting; October 1-5, 2018; Berlin, Germany.

Potential cost-effectiveness of wearable cardioverter-defibrillator for patients with implantable cardioverter-defibrillator explant in a high-income city of China.

INTRODUCTION: Wearable cardioverter-defibrillator (WCD) is recommended for patients with implantable cardioverter-defibrillator (ICD) removal. This study aimed to investigate the potential cost-effectiveness of WCD for patients with ICD explant in a high-income city of China. METHODS AND RESULTS: A 5-year decision-analytic model was developed to simulate outcomes of three strategies during the period between ICD explant and reimplantation: discharge-to-home without WCD (home group), discharge-to-home with WCD (WCD group), and stay-in-hospital (hospital group). Outcome measures were mortality rates (during the period between ICD explant and reimplantation), direct medical costs, quality-adjusted life years (QALYs), and incremental cost per QALY saved (ICER). Model inputs were derived from literature and public data. Base-case analysis was performed at four cost levels of WCD. Robustness of model results was examined by sensitivity analyses. In base-case analysis, the 8-week mortality rates of WCD, hospital, and home groups were 7.3%, 8.1%, and 9.4%, respectively. WCD group gained the highest QALYs (3.0990 QALYs), followed by hospital group (3.0553 QALYs) and home group (3.0132 QALYs). The WCD group was the cost-effective option with ICERs less than willingness-to-pay (WTP) threshold (57 315 USD/QALY) at WCD daily cost ≤USD48. In probabilistic sensitivity analysis, the WCD group at daily cost of USD24, USD48, USD72, and USD96 were cost-effective in 100%, 94.16%, 22.08%, and 0.16% of 10 000 Monte Carlo simulations, respectively. CONCLUSIONS: Use of WCD during the period between ICD explant and reimplantation is likely to save life and gain higher QALYs. Cost-effectiveness of WCD is highly subject to the daily cost of WCD in China.

Continuous Glucose Monitoring Sensors for Diabetes Management: A Review of Technologies and Applications.

By providing blood glucose (BG) concentration measurements in an almost continuous-time fashion for several consecutive days, wearable minimally-invasive continuous glucose monitoring (CGM) sensors are revolutionizing diabetes management, and are becoming an increasingly adopted technology especially for diabetic individuals requiring insulin administrations. Indeed, by providing glucose real-time insights of BG dynamics and trend, and being equipped with visual and acoustic alarms for hypo- and hyperglycemia, CGM devices have been proved to improve safety and effectiveness of diabetes therapy, reduce hypoglycemia incidence and duration, and decrease glycemic variability. Furthermore, the real-time availability of BG values has been stimulating the realization of new tools to provide patients with decision support to improve insulin dosage tuning and infusion. The aim of this paper is to offer an overview of current literature and future possible developments regarding CGM technologies and applications. In particular, first, we outline the technological evolution of CGM devices through the last 20 years. Then, we discuss about the current use of CGM sensors from patients affected by diabetes, and, we report some works proving the beneficial impact provided by the adoption of CGM. Finally, we review some recent advanced applications for diabetes treatment based on CGM sensors.

Low-Cost and Highly Sensitive Wearable Sensor Based on Napkin for Health Monitoring.

The development of sensors with high sensitivity, good flexibility, low cost, and capability of detecting multiple inputs is of great significance for wearable electronics. Herein, we report a napkin-based wearable capacitive sensor fabricated by a novel, low-cost, and facile strategy. The capacitive sensor is composed of two pieces of electrode plates manufactured by spontaneous assembly of silver nanowires (NWs) on a polydimethylsiloxane (PDMS)-patterned napkin. The sensor possesses high sensitivity (>7.492 kPa-1), low cost, and capability for simultaneous detection of multiple signals. We demonstrate that the capacitive sensor can be applied to identify a variety of human physiological signals, including finger motions, eye blinking, and minute wrist pulse. More interestingly, the capacitive sensor comfortably attached to the temple can simultaneously monitor eye blinking and blood pulse. The demonstrated sensor shows great prospects in the applications of human-machine interface, prosthetics, home-based healthcare, and flexible touch panels.

Ultralow-Cost, Highly Sensitive, and Flexible Pressure Sensors Based on Carbon Black and Airlaid Paper for Wearable Electronics.

Flexible pressure sensors have attracted considerable attention because of their potential applications in healthcare monitoring and human-machine interactions. However, the complicated fabrication process and the cos of sensing materials limit their widespread applications in practice. Herein, a flexible pressure sensor with outstanding performances is presented through an extremely simple and cost-efficient fabrication process. The sensing materials of the sensor are based on low-cost carbon black (CB)@airlaid paper (AP) composites, which are just prepared by drop-casting CB solutions onto APs. Through simply stacking multiple CB@APs with an irregular surface and a fiber-network structure, the obtained pressure sensor demonstrates an ultrahigh sensitivity of 51.23 kPa-1 and an ultralow detection limit of 1 Pa. Additionally, the sensor exhibits fast response time, wide working range, good stability, as well as excellent flexibility and biocompatibility. All the comprehensive and superior performances endow the sensor with abilities to precisely detect weak air flow, wrist pulse, phonation, and wrist bending in real time. In addition, an array electronic skin integrated with multiple CB@AP sensors has been designed to identify spatial pressure distribution and pressure magnitude. Through a biomimetic structure inspired by blooming flowers, a sensor with the open-petal structure has been designed to recognize the wind direction. Therefore, our study, which demonstrates a flexible pressure sensor with low cost, simple preparation, and superior performances, will open up for the exploration of cost-efficient pressure sensors in wearable devices.