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ACS Appl Mater Interfaces 2021 Apr 6. Epub 2021 Apr 6.

IMEC, Kapeldreef 75, Leuven 3001, Belgium.

Thin-film organic near-infrared (NIR) photodiodes can be essential building blocks in the rapidly emerging fields including the internet of things and wearable electronics. However, the demonstration of NIR organic photodiodes with not only high responsivity but also low dark current density that is comparable to that of inorganic photodiodes, for example, below 1 nA cm for silicon photodiodes, remains a challenge. In this work, we have demonstrated non-fullerene acceptor-based NIR photodiodes with an ultralow dark current density of 0. Read More

J Alzheimers Dis 2021 Apr 1. Epub 2021 Apr 1.

Department of Industrial Engineering, University of Florence, Florence, Italy.

Background: Social apathy, a reduction in initiative in proposing or engaging in social activities or interactions, is common in mild neurocognitive disorders (MND). Current apathy assessment relies on self-reports or clinical scales, but growing attention is devoted to defining more objective, measurable and non-invasive apathy proxies.

Objective: In the present study we investigated the interest of recording action kinematics in a social reach-to-grasp task for the assessment of social apathy. Read More

Sensors (Basel) 2021 Mar 16;21(6). Epub 2021 Mar 16.

École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.

This article describes the design and the characterization of the ANTIGONE (ANalog To dIGital cONvErter) ASIC (Application Specific Integrated Circuit) built in AMS 0.35 m technology for low dc-current sensing. This energy-efficient ASIC was specifically designed to interface with multiple Ion-Sensitive Field-Effect Transistors (ISFETs) and detect biomarkers like pH, Na+, K+ and Ca2+ in human sweat. Read More

ACS Biomater Sci Eng 2021 04 29;7(4):1651-1662. Epub 2021 Mar 29.

Unconventional Computing Laboratory, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, United Kingdom.

The bacterial skin studied here is a several centimeter-wide colony of living on a cellulose-based hydrogel. We demonstrate that the colony exhibits trains of spikes of extracellular electrical potential, with amplitudes of the spikes varying from 1 to 17 mV. The bacterial pad responds to mechanical stimulation with distinctive changes in its electrical activity. Read More

BMC Musculoskelet Disord 2021 Mar 3;22(1):242. Epub 2021 Mar 3.

Department of Research, Sint Maartenskliniek, Hengstdal 3, 6574 NA Ubbergen, Nijmegen, The Netherlands.

Background: Although it is well-established that osteoarthritis (OA) impairs daily-life gait, objective gait assessments are not part of routine clinical evaluation. Wearable inertial sensors provide an easily accessible and fast way to routinely evaluate gait quality in clinical settings. However, during these assessments, more complex and meaningful aspects of daily-life gait, including turning, dual-task performance, and upper body motion, are often overlooked. Read More

ACS Cent Sci 2021 Feb 18;7(2):335-344. Epub 2021 Jan 18.

Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Binshui Xi dao 391, Xiqing District, 300384 Tianjin, China.

Rechargeable Na-air batteries (NABs) based on abundant Na resources are generating great interest due to their high energy density and low cost. However, Na anode corrosion in ambient air and the growth of abnormal dendrites lead to insufficient cycle performance and safety hazards. Effectively protecting the Na anode from corrosion and inducing the uniform Na plating and stripping are therefore of vital importance for practical application. Read More

Mikrochim Acta 2021 Feb 23;188(3):97. Epub 2021 Feb 23.

Department of Electronic Engineering, Kwangwoon University, Seoul, Republic of Korea.

A nature-inspired special structure of bismuth is newly presented as Zn ion sensing layer for high-performance electrochemical heavy metal detection sensor applications. The rime ice-like bismuth (RIBi) has been synthesized using an easy ex situ electrodeposition method on the surface of a flexible graphene-based electrode. The flexible graphene-based electrode was fabricated via simple laser-writing and substrate-transfer techniques. Read More

ACS Appl Mater Interfaces 2021 Feb 15;13(7):8889-8900. Epub 2021 Feb 15.

Department of Advanced Materials, Hannam University, Daejeon 34054, Republic of Korea.

Polyampholyte (PA) hydrogels have great potential for biomedical applications, owing to their high toughness and good self-recovery and self-healing (SELF) behavior in addition to their physical properties similar to human tissue. However, their implementation as practical biomedical skin patches or wearable devices has so far been limited by their insufficient transdermal adhesion strength. In this work, a new polyampholytic terpolymer (PAT) hydrogel with enhanced skin adhesion was developed using a novel and simple strategy that tunes the structure of ion-pair associations (IPAs), acting as cross-links, in the hydrogel via adding an extra neutral monomer component into the network without changing the total charge balance. Read More

Sci Adv 2021 01 27;7(5). Epub 2021 Jan 27.

State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China.

This paper reports a flexible electronics-based epidermal biomicrofluidics technique for clinical continuous blood glucose monitoring, overcoming the drawback of the present wearables, unreliable measurements. A thermal activation method is proposed to improve the efficiency of transdermal interstitial fluid (ISF) extraction, enabling extraction with a low current density to notably reduce skin irritation. An Na sensor and a correction model are proposed to eliminate the effect of individual differences, which leads to fluctuations in the amount of ISF extraction. Read More

ACS Sens 2021 03 31;6(3):1174-1186. Epub 2021 Jan 31.

Electrodics and Electrocatalysis Division, CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi 630003, Tamil Nadu, India.

Although the recent advancement in wearable biosensors provides continuous, noninvasive assessment of physiologically relevant chemical markers from human sweat, several bottlenecks still exist for its practical use. There were challenges in developing a multiplexed biosensing system with rapid microfluidic sampling and transport properties, as well as its integration with a portable potentiostat for improved interference-free data collection. Here, we introduce a clean-room free fabrication of wearable microfluidic sensors, using a screen-printed carbon master, for the electrochemical monitoring of sweat biomarkers during exercise activities. Read More

Biosens Bioelectron 2021 Mar 25;176:112933. Epub 2020 Dec 25.

Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, North Carolina State University, Chapel Hill, NC, 27599, USA. Electronic address:

The development of wearable multiplexed biosensors has been focused on systems to measure sweat l-lactate and other metabolites, where the employment of the direct electron transfer (DET) principle is expected. In this paper, a fusion enzyme between an engineered l-lactate oxidase derived from Aerococcus viridans, AvLOx A96L/N212K mutant, which is minimized its oxidase activity and b-type cytochrome protein was constructed to realize multiplexed DET-type lactate and glucose sensors. The sensor with a fusion enzyme showed DET to a gold electrode, with a limited operational range less than 0. Read More

Sens Actuators A Phys 2020 Apr 21;305. Epub 2020 Feb 21.

Thayer School of Engineering, Dartmouth College, Hanover, NH 03755.

Piezoelectric nanomaterial-polymer composites represent a unique paradigm for making flexible energy harvesting and sensing devices with enhanced devices' performance. In this work, we studied various metal doped ZnO nanostructures, fabricated and characterized ZnO nanoparticle-PVDF composite thin film, and demonstrated both enhanced energy generation and motion sensing capabilities. Specifically, a series of flexible piezoelectric nanogenerators (PENGs) were designed based on these piezoelectric composite thin films. Read More

ACS Appl Mater Interfaces 2021 Jan 28;13(1):745-754. Epub 2020 Dec 28.

Christopher Ingold Laboratory, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.

Aqueous zinc-ion batteries (AZIBs) have the potential to be utilized in a grid-scale energy storage system owing to their high energy density and cost-effective properties. However, the dissolution of cathode materials and the irreversible extraction of preintercalated metal ions in the electrode materials restrict the stability of AZIBs. Herein, a cathode-stabilized ZIB strategy is reported based on a natural biomass polymer sodium alginate as the electrolyte coupling with a Na preintercalated δ-NaMnO·1. Read More

Nanotechnology 2021 Apr;32(14):145401

Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Hwarangro 14 Gil 5, Sungbuk Gu, Seoul, 02792, Republic of Korea. Department of Electronic, Electrical, and Computer Engineering, College of Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.

Coaxial type piezoelectric energy generator (C-PEG) nanofiber was fabricated by a self-designed continuous electrospinning deposition system. Piezoelectric PVDF-TrFE nanofiber as an electroactive material was electrospun at a discharge voltage of 9-12 kV onto a simultaneously rotating and transverse moving Cu metal wire at an angular velocity of ω  = 60-120 RPM. The piezoelectric coefficient d of the PVDF-TrFE nanofiber was approximately -20 pm V. Read More

Anal Methods 2020 12;12(48):5885-5892

Delft University of Technology, Faculty of Electrical Engineering, Mathematics & Computer Science, Mekelweg 4, Delft, 2628 CD, The Netherlands.

This paper presents a method to continuously collect and reliably measure sweat analyte concentrations during exercise. The method can be used to validate newly developed sweat sensors and to obtain insight into intraindividual variations of sweat analytes in athletes. First, a novel design of a sweat collection system is created. Read More

J Clin Med 2020 Nov 22;9(11). Epub 2020 Nov 22.

Department of Rehabilitation Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.

People with diabetic peripheral neuropathy (DPN) experience lower quality of life caused by associated balance, posture, and gait impairments. While focal muscle vibration (FMV) has been associated with improvements in gait performance in individuals with neurological disorders, little is known about its effectiveness in patients with DPN. The purpose of this study was to investigate the effect of FMV on gait outcomes in patients with DPN. Read More

Biosens Bioelectron 2021 Feb 19;174:112828. Epub 2020 Nov 19.

Engineering Research Center of Advanced Glasses Manufacturing Technology, Ministry of Education, Donghua University, Shanghai, 201620, PR China.

Wearable electrochemical sensors have attracted tremendous attention in recent years. Significant progress has been achieved, particularly in device integration. Most wearable devices are integrated on thin-film polymer, however, less attention is paid to the sweat flow at human-device interfaces, which is of great significance for continuous real-time analysis and long-term skin comfort. Read More

Talanta 2021 Jan 9;222:121502. Epub 2020 Aug 9.

Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy; SENSE4MED, via Renato Rascel 30, 00128, Rome, Italy. Electronic address:

In the last decade, wearable sensors have gained a key role on biomedical research field for reliable health state monitoring. A wide plethora of physics marker sensors is already commercially available, including activity tracker, heart rate devices, and fitness smartwatch. On the contrary, wearable and epidermal sensors for chemical biomarker monitoring in several biofluids are not ready yet. Read More

Sensors (Basel) 2020 Nov 4;20(21). Epub 2020 Nov 4.

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.

Kinetics data such as ground reaction forces (GRFs) are commonly used as indicators for rehabilitation and sports performance; however, they are difficult to measure with convenient wearable devices. Therefore, researchers have attempted to estimate accurately unmeasured kinetics data with artificial neural networks (ANNs). Because the inputs to an ANN affect its performance, they must be carefully selected. Read More

Sensors (Basel) 2020 Oct 22;20(21). Epub 2020 Oct 22.

Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Pohang 37673, Korea.

This paper presents an energy-optimized electronic performance tracking system (EPTS) device for analyzing the athletic movements of football players. We first develop a tiny battery-operated wearable device that can be attached to the backside of field players. In order to analyze the strategic performance, the proposed wearable EPTS device utilizes the GNSS-based positioning solution, the IMU-based movement sensing system, and the real-time data acquisition protocol. Read More

Lab Chip 2020 11;20(22):4205-4214

Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA and California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA and Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA. and Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90064, USA and Department of Radiology, University of California-Los Angeles, Los Angeles, CA 90095, USA and Department of Chemical and Biomolecular Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.

Microchannels in hydrogels play an essential role in enabling a smart contact lens. However, microchannels have rarely been created in commercial hydrogel contact lenses due to their sensitivity to conventional microfabrication techniques. Here, we report the fabrication of microchannels in poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels that are used in commercial contact lenses with a three-dimensional (3D) printed mold. Read More

Annu Int Conf IEEE Eng Med Biol Soc 2020 07;2020:5184-5187

Long-term preclinical study available extracranial brain activator (ECBA) system, ECBAv2, is proposed for the non-anesthetic canine models. The titanium-packaged module shows enhanced durability, even after a year of implantation in the scalp. In addition, the wearable helmet type base station provides a stable experimental environment without anesthesia. Read More

Sensors (Basel) 2020 Sep 28;20(19). Epub 2020 Sep 28.

Center for Orthopaedic Biomechanics, University of Denver, Denver, CO 80208, USA.

Quantitative assessments of patient movement quality in osteoarthritis (OA), specifically spatiotemporal gait parameters (STGPs), can provide in-depth insight into gait patterns, activity types, and changes in mobility after total knee arthroplasty (TKA). A study was conducted to benchmark the ability of multiple deep neural network (DNN) architectures to predict 12 STGPs from inertial measurement unit (IMU) data and to identify an optimal sensor combination, which has yet to be studied for OA and TKA subjects. DNNs were trained using movement data from 29 subjects, walking at slow, normal, and fast paces and evaluated with cross-fold validation over the subjects. Read More

Sensors (Basel) 2020 Sep 26;20(19). Epub 2020 Sep 26.

Faculty of Health, University Witten/Herdecke, 58448 Witten, Germany.

Atrial fibrillation (AF) is the most common arrhythmia and has a major impact on morbidity and mortality; however, detection of asymptomatic AF is challenging. This study sims to evaluate the sensitivity and specificity of non-invasive AF detection by a medical wearable. In this observational trial, patients with AF admitted to a hospital carried the wearable and an ECG Holter (control) in parallel over a period of 24 h, while not in a physically restricted condition. Read More

J Med Syst 2020 Sep 23;44(11):190. Epub 2020 Sep 23.

Department of Research and Development, Pluryn, P.O. Box 53, 6500, AB, Nijmegen, The Netherlands.

Wearable monitoring devices are an innovative way to measure heart rate (HR) and heart rate variability (HRV), however, there is still debate about the validity of these wearables. This study aimed to validate the accuracy and predictive value of the Empatica E4 wristband against the VU University Ambulatory Monitoring System (VU-AMS) in a clinical population of traumatized adolescents in residential care. A sample of 345 recordings of both the Empatica E4 wristband and the VU-AMS was derived from a feasibility study that included fifteen participants. Read More

Sensors (Basel) 2020 Sep 18;20(18). Epub 2020 Sep 18.

Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.

Background: Movement characteristics can differentiate between infants at risk and infants with typical development. However, it is unknown how many days are needed to accurately represent typical daily behavior for infants at risk of developmental disabilities when using wearable sensors. To consider the balance between participant burden and the amount of data collected and optimizing the efficiency of data collection, our study determined (1) how many days were necessary to represent typical movement behavior for infants at risk of developmental disabilities and (2) whether movement behavior was different on weekend days and weekdays. Read More

Sci Technol Adv Mater 2020 Jun 24;21(1):379-387. Epub 2020 Jun 24.

Department of Mechanical Engineering, School of Engineering, the University of Tokyo, Tokyo, Japan.

A paper-based electrode is a very attractive component for a disposable, nontoxic, and flexible biosensor. In particular, wearable biosensors, which have recently been attracting interest, not only require these characteristics of paper-based electrodes but must also be able to detect various ions and biomolecules in biological fluids. In this paper, we demonstrate the detection ability of paper-based metal electrodes for wearable biosensors as part of a wireless potentiometric measurement system, focusing on the detection of pH and sodium ions. Read More

Sensors (Basel) 2020 Sep 4;20(18). Epub 2020 Sep 4.

Université Côte d'Azur, LAMHESS, EUR HEALTHY, 06205 Nice, France.

Wearable sensors have recently been used to evaluate biomechanical parameters of everyday movements, but few have been located at the head level. This study investigated the relative and absolute reliability (intra- and inter-session) and concurrent validity of an inertial measurement unit (IMU) embedded in smart eyeglasses during sit-to-stand (STS) movements for the measurement of maximal acceleration of the head. Reliability and concurrent validity were investigated in nineteen young and healthy participants by comparing the acceleration values of the glasses' IMU to an optoelectronic system. Read More

Talanta 2020 Nov 30;219:121145. Epub 2020 May 30.

Insight Centre for Data Analytics, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland. Electronic address:

The SwEatch platform, a wearable sensor for sampling and measuring the concentration of electrolytes in human sweat in real time, has been improved in order to allow the sensing of two analytes. The solid contact ion-sensitive electrodes (ISEs) for the detection of Na and K have been developed in two alternative formulations, containing either poly(3,4-ethylenedioxythiophene) (PEDOT) or poly(3-octylthiophene-2,5-diyl) (POT) as a conductive polymer transducing component. The solution-processable POT formulation simplifies the fabrication process, and sensor to sensor reproducibility has been improved via partial automation using an Opentron® automated pipetting robot. Read More

ACS Appl Mater Interfaces 2020 Sep 21;12(35):39342-39351. Epub 2020 Aug 21.

CAS Center for Excellence in Nanoscience, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences; Beijing 100083, China.

In order to satisfy the increasing requirements on operation time of wearable and portable electronic devices, novel self-powered systems by integrating triboelectric nanogenerator (TENG) with an energy storage device have emerged as a promising technology to provide sustainable power. Here, a flexible sodium composite anode (Na@CC) was prepared by infusing the molten sodium into flexible sodiophilic carbon cloth. The symmetric cell with the Na@CC anode shows stable sodium plating and stripping for 400 h. Read More