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Zhao Y, Yang Y, Wan B, Ding T, Sha X. Enhancement of the Electric-Force Response of Carbon Black/Silicone Rubber Composites by Silane Coupling Agents. Molecules 2024; 29:2740. [PMID: 38930805 PMCID: PMC11205836 DOI: 10.3390/molecules29122740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/30/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Flexible strain sensors have a wide range of applications in the field of health monitoring of seismic isolation bearings. However, the nonmonotonic response with shoulder peaks limits their application in practical engineering. Here we eliminate the shoulder peak phenomenon during the resistive-strain response by adjusting the dispersion of conductive nanofillers. In this paper, carbon black (CB)/methyl vinyl silicone rubber (VMQ) composites were modified by adding a silane coupling agent (KH550). The results show that the addition of KH550 eliminates the shoulder peak phenomenon in the resistive response signal of the composites. The reason for the disappearance of the shoulder peak phenomenon was explained, and at the same time, the mechanical properties of the composites were enhanced, the percolation threshold was reduced, and they had excellent strain-sensing properties. It also exhibited excellent stability and repeatability during 18,000 cycles of loading-unloading. The resistance-strain response mechanism was explained by the tunneling effect theoretical model analysis. It was shown that the sensor has a promising application in the health monitoring of seismic isolation bearings.
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Affiliation(s)
- Yanfang Zhao
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China; (Y.Z.); (B.W.); (T.D.); (X.S.)
- Yunnan Key Laboratory of Disaster Reduction in Civil Engineering, Kunming 650500, China
- International Joint Laboratory for Green Construction and Intelligent Maintenance of Yunnan Province, Kunming 650500, China
| | - Yang Yang
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China; (Y.Z.); (B.W.); (T.D.); (X.S.)
- Yunnan Key Laboratory of Disaster Reduction in Civil Engineering, Kunming 650500, China
- International Joint Laboratory for Green Construction and Intelligent Maintenance of Yunnan Province, Kunming 650500, China
| | - Bangwei Wan
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China; (Y.Z.); (B.W.); (T.D.); (X.S.)
- Yunnan Key Laboratory of Disaster Reduction in Civil Engineering, Kunming 650500, China
- International Joint Laboratory for Green Construction and Intelligent Maintenance of Yunnan Province, Kunming 650500, China
| | - Tianyu Ding
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China; (Y.Z.); (B.W.); (T.D.); (X.S.)
- Yunnan Key Laboratory of Disaster Reduction in Civil Engineering, Kunming 650500, China
- International Joint Laboratory for Green Construction and Intelligent Maintenance of Yunnan Province, Kunming 650500, China
| | - Xun Sha
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China; (Y.Z.); (B.W.); (T.D.); (X.S.)
- Yunnan Key Laboratory of Disaster Reduction in Civil Engineering, Kunming 650500, China
- International Joint Laboratory for Green Construction and Intelligent Maintenance of Yunnan Province, Kunming 650500, China
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Kaplan M, Alp E, Krause B, Pötschke P. Improvement of the Piezoresistive Behavior of Poly (vinylidene fluoride)/Carbon Nanotube Composites by the Addition of Inorganic Semiconductor Nanoparticles. MATERIALS (BASEL, SWITZERLAND) 2024; 17:774. [PMID: 38399025 PMCID: PMC10890062 DOI: 10.3390/ma17040774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024]
Abstract
Conductive polymer composites (CPCs), obtained by incorporating conductive fillers into a polymer matrix, are suitable for producing strain sensors for structural health monitoring (SHM) in infrastructure. Here, the effect of the addition of inorganic semiconductor nanoparticles (INPs) to a poly (vinylidene fluoride) (PVDF) composite filled with multi-walled carbon nanotubes (MWCNTs) on the piezoresistive behavior is investigated. INPs with different morphologies and sizes are synthesized by a hydrothermal method. The added inorganic oxide semiconductors showed two distinct morphologies, including different phases. While particles with flower-like plate morphology contain phases of orth-ZnSnO3 and SnO, the cauliflower-like nanoparticles contain these metal oxides and ZnO. The nanoparticles are characterized by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), and the nanocomposites by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Cyclic tensile testing is applied to determine the strain-sensing behavior of PVDF/1 wt% MWCNT nanocomposites with 0-10 wt% inorganic nanoparticles. Compared to the PVDF/1 wt% MWCNT nanocomposite, the piezoresistive sensitivity is higher after the addition of both types of nanoparticles and increases with their amount. Thereby, nanoparticles with flower-like plate structures improve strain sensing behavior slightly more than nanoparticles with cauliflower-like structures. The thermogravimetric analysis results showed that the morphology of the semiconductor nanoparticles added to the PVDF/MWCNT matrix influences the changes in thermal properties.
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Affiliation(s)
- Müslüm Kaplan
- Faculty of Engineering, Architecture and Design, Bartin University, Bartin 74110, Turkey; (M.K.); (E.A.)
- Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Str. 6, 01069 Dresden, Germany;
| | - Emre Alp
- Faculty of Engineering, Architecture and Design, Bartin University, Bartin 74110, Turkey; (M.K.); (E.A.)
| | - Beate Krause
- Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Str. 6, 01069 Dresden, Germany;
| | - Petra Pötschke
- Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Str. 6, 01069 Dresden, Germany;
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Zhu T, Wu K, Wang Y, Zhang J, Liu G, Sun J. Highly stable and strain-insensitive metal film conductors via manipulating strain distribution. MATERIALS HORIZONS 2023; 10:5920-5930. [PMID: 37873924 DOI: 10.1039/d3mh01399e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Metal film-based stretchable conductors are essential elements of flexible electronics for wearable, biomedical, and robotic applications, which require strain-insensitive high conductivity over a wide strain range and excellent cyclic stability. However, they suffer from serious electrical failure under monotonic and cyclic tensile loading at a small strain due to the uncontrolled film cracking behavior. Here, we propose a novel in-plane crack control strategy of engineering hierarchical microstructures to achieve outstanding electromechanical performance via harnessing the strain distribution in metal films. The wrinkles delay the crack initiation at undercuts which should be the most vulnerable sites during the stretching process. The surface protrusions/grooves/undercuts inhibit the crack propagation because of the effective strain redistribution. In addition, hierarchical microstructures significantly improve cyclic stability due to the strong interfacial adhesion and stable crack patterns. The metal film-based conductors exhibit ultrahigh strain-insensitive conductivity (1.7 × 107 S m-1), negligible resistance change (ΔR/R0 = 0.007) over an ultra-wide strain range (>200%), and excellent cyclic strain durability (>15 000 cycles at 100% strain). A range of metal films was explored to establish the universality of this strategy, including ductile copper and silver, as well as brittle molybdenum and high entropy alloy. We demonstrate the strain-insensitive electrical functionality of a metal film-based conductor in a flexible light-emitting diode circuit.
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Affiliation(s)
- Ting Zhu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Kai Wu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Yaqiang Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Jinyu Zhang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Gang Liu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
| | - Jun Sun
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
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Futane A, Senthil M, S J, Srinivasan A, R K, Narayanamurthy V. Sweat analysis for urea sensing: trends and challenges. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:4405-4426. [PMID: 37646163 DOI: 10.1039/d3ay01089a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
With increasing population there is a rise in pathological diseases that the healthcare facilities are grappling with. Sweat-based wearable technologies for continuous monitoring have overcome the demerits associated with sweat sampling and sensing. Hence, sweat as an alternative biofluid holds great promise for the quantification of a host of biomarkers and understanding the functioning of the body, thereby deducing ailments quickly and economically. This comprehensive review accounts for recent advances in sweat-based LOCs (Lab-On-Chips), which are a likely alternative to the existing blood-urea sample testing that is invasive and time-consuming. The present review is focused on the advancements in sweat-based Lab-On-Chips (LOCs) as an alternative to invasive and time-consuming blood-urea sample testing. In addition, different sweat collection methods (direct skin, near skin and microfluidic) and their mechanism for urea sensing are explained in detail. The mechanism of urea in biofluids in protein metabolism, balancing nitrogen levels and a crucial factor of kidney function is described. In the end, research and technological advancements are explained to address current challenges and enable its widespread implementation.
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Affiliation(s)
- Abhishek Futane
- Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia
| | - Mallika Senthil
- Department of Biomedical Engineering, Rajalakshmi Engineering, College, Chennai, India 602105
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Jayashree S
- Department of Biomedical Engineering, Rajalakshmi Engineering, College, Chennai, India 602105
| | - Arthi Srinivasan
- Faculty of Chemical and Process Engineering Technology, University Malaysia Pahang (UMP), Lebuhraya Tun Razak, 26300 Gambang, Kunatan, Pahang, Malaysia
| | - Kalpana R
- Department of Biomedical Engineering, Rajalakshmi Engineering, College, Chennai, India 602105
| | - Vigneswaran Narayanamurthy
- Advance Sensors and Embedded Systems (ASECs), Centre for Telecommunication Research & Innovation, Fakulti Teknologi Kejuruteraan Elektrik Dan Elektronik, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal, Melaka 76100, Malaysia
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India.
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5
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Xie L, Zhang Z, Wu Q, Gao Z, Mi G, Wang R, Sun HB, Zhao Y, Du Y. Intelligent wearable devices based on nanomaterials and nanostructures for healthcare. NANOSCALE 2023; 15:405-433. [PMID: 36519286 DOI: 10.1039/d2nr04551f] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Emerging classes of flexible electronic sensors as alternatives to conventional rigid sensors offer a powerful set of capabilities for detecting and quantifying physiological and physical signals from human skin in personal healthcare. Unfortunately, the practical applications and commercialization of flexible sensors are generally limited by certain unsatisfactory aspects of their performance, such as biocompatibility, low sensing range, power supply, or single sensory function. This review intends to provide up-to-date literature on wearable devices for smart healthcare. A systematic review is provided, from sensors based on nanomaterials and nanostructures, algorithms, to multifunctional integrated devices with stretchability, self-powered performance, and biocompatibility. Typical electromechanical sensors are investigated with a specific focus on the strategies for constructing high-performance sensors based on nanomaterials and nanostructures. Then, the review emphasizes the importance of tailoring the fabrication techniques in order to improve stretchability, biocompatibility, and self-powered performance. The construction of wearable devices with high integration, high performance, and multi-functionalization for multiparameter healthcare is discussed in depth. Integrating wearable devices with appropriate machine learning algorithms is summarized. After interpretation of the algorithms, intelligent predictions are produced to give instructions or predictions for smart implementations. It is desired that this review will offer guidance for future excellence in flexible wearable sensing technologies and provide insight into commercial wearable sensors.
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Affiliation(s)
- Liping Xie
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Zelin Zhang
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Qiushuo Wu
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Zhuxuan Gao
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Gaotian Mi
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Renqiao Wang
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Hong-Bin Sun
- Department of Chemistry, Northeastern University, Shenyang, 110819, China
| | - Yue Zhao
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China.
| | - Yanan Du
- Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China
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Kumar A, Rakesh Kumar RK, Shaikh MO, Lu CH, Yang JY, Chang HL, Chuang CH. Ultrasensitive Strain Sensor Utilizing a AgF-AgNW Hybrid Nanocomposite for Breath Monitoring and Pulmonary Function Analysis. ACS APPLIED MATERIALS & INTERFACES 2022; 14:55402-55413. [PMID: 36485002 DOI: 10.1021/acsami.2c17756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Breath monitoring and pulmonary function analysis have been the prime focus of wearable smart sensors owing to the COVID-19 outbreak. Currently used lung function meters in hospitals are prone to spread the virus and can result in the transmission of the disease. Herein, we have reported the first-ever wearable patch-type strain sensor for enabling real-time lung function measurements (such as forced volume capacity (FVC) and forced expiratory volume (FEV) along with breath monitoring), which can avoid the spread of the virus. The noninvasive and highly sensitive strain sensor utilizes the synergistic effect of two-dimensional (2D) silver flakes (AgFs) and one-dimensional (1D) silver nanowires (AgNWs), where AgFs create multiple electron transmission paths and AgNWs generate percolation networks in the nanocomposite. The nanocomposite-based strain sensor possesses a high optimized conductivity of 7721 Sm-1 (and a maximum conductivity of 83,836 Sm-1), excellent stretchability (>1000%), and ultrasensitivity (GFs of 35 and 87 when stretched 0-20 and 20-50%, respectively), thus enabling reliable detection of small strains produced by the body during breathing and other motions. The sensor patching site was optimized to accurately discriminate between normal breathing, quick breathing, and deep breathing and analyze numerous pulmonary functions, including the respiratory rate, peak flow, FVC, and FEV. Finally, the observed measurements for different pulmonary functions were compared with a commercial peak flow meter and a spirometer, and a high correlation was observed, which highlights the practical feasibility of continuous respiratory monitoring and pulmonary function analysis.
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Affiliation(s)
- Amit Kumar
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung80424, Taiwan
| | - R K Rakesh Kumar
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung80424, Taiwan
| | - Muhammad Omar Shaikh
- Sustainability Science and Engineering Program, Tunghai University, Taichung407224, Taiwan
| | - Cheng-Huan Lu
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung80424, Taiwan
| | - Jia-Yu Yang
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung80424, Taiwan
| | - Hsu-Liang Chang
- Department of Internal Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung80145, Taiwan
| | - Cheng-Hsin Chuang
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung80424, Taiwan
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7
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Fei Y, Jiang R, Fang W, Liu T, Saeb MR, Hejna A, Ehsani M, Barczewski M, Sajadi SM, Chen F, Kuang T. Highly sensitive large strain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite foams: From design to performance evaluation. J Supercrit Fluids 2022. [DOI: 10.1016/j.supflu.2022.105653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Zheng Z, Zhao Y, Ye Z, Hu J, Wang H. Electrically conductive porous MXene-polymer composites with ultralow percolation threshold via Pickering high internal phase emulsion templating strategy. J Colloid Interface Sci 2022; 618:290-299. [PMID: 35344882 DOI: 10.1016/j.jcis.2022.03.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/08/2022] [Accepted: 03/20/2022] [Indexed: 10/18/2022]
Abstract
HYPOTHESIS Constructing a segregated network in electrically conductive polymer composites (ECPCs) is an effective method to lower the electrical percolation threshold. The segregated network structure can be formed naturally via polymerizing Pickering high internal phase emulsions (HIPEs) because solid particles are assembled at water-oil interfaces. However, most Pickering stabilizers show poor electrical conductivity. In this work, we propose a facile method to prepare lightweight ECPCs with well-controlled segregated structure via Ti3C2Tx-stabilized HIPE templating. EXPERIMENTS Hydrophilic Ti3C2Tx flakes are delicately hydrophobized with a double-chain cation surfactant. The morphology of Ti3C2Tx flakes is investigated by transmission electron microscopy (TEM) and atom force microscopy (AFM). The surface properties of modified Ti3C2Tx are characterized by zeta potential and water contact angle tests. The stability of Ti3C2Tx-stabilized emulsions, and the structure of prepared ECPCs are systematically investigated. FINDINGS Surface modified Ti3C2Tx flakes are used to stabilize water-in-oil (w/o) HIPEs for the first time. After the polymerization of continuous oil phase, ECPCs are successfully prepared with closed-cell porous structure. The pore size and size distribution of porous composites can be tailored by varying the content of Ti3C2Tx flakes. The Ti3C2Tx flakes are mainly immobilized at the water-oil interface and eventually form the segregated network in composites. Combining the unique segregated network and the outstanding metallic conductivity of Ti3C2Tx, the prepared porous polymer composites exhibit good conductivity even with ultralow Ti3C2Tx content of 0.016 vol%.
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Affiliation(s)
- Zheng Zheng
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yongliang Zhao
- Shanghai Dilato Materials Co., Ltd, Shanghai 200433, China
| | - Zhangfan Ye
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Jianhua Hu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Haitao Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
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Zhou J, Long X, Huang J, Jiang C, Zhuo F, Guo C, Li H, Fu Y, Duan H. Multiscale and hierarchical wrinkle enhanced graphene/Ecoflex sensors integrated with human-machine interfaces and cloud-platform. NPJ FLEXIBLE ELECTRONICS 2022; 6:55. [PMID: 37520266 PMCID: PMC9255543 DOI: 10.1038/s41528-022-00189-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/08/2022] [Indexed: 06/16/2023]
Abstract
Current state-of-the-art stretchable/flexible sensors have received stringent demands on sensitivity, flexibility, linearity, and wide-range measurement capability. Herein, we report a methodology of strain sensors based on graphene/Ecoflex composites by modulating multiscale/hierarchical wrinkles on flexible substrates. The sensor shows an ultra-high sensitivity with a gauge factor of 1078.1, a stretchability of 650%, a response time of ~140 ms, and a superior cycling durability. It can detect wide-range physiological signals including vigorous body motions, pulse monitoring and speech recognition, and be used for monitoring of human respirations in real-time using a cloud platform, showing a great potential for the healthcare internet of things. Complex gestures/sign languages can be precisely detected. Human-machine interface is demonstrated by using a sensor-integrated glove to remotely control an external manipulator to remotely defuse a bomb. This study provides strategies for real-time/long-range medical diagnosis and remote assistance to perform dangerous tasks in industry and military fields.
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Affiliation(s)
- Jian Zhou
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Xinxin Long
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Jian Huang
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Caixuan Jiang
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Fengling Zhuo
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Chen Guo
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
| | - Honglang Li
- National Center for Nanoscience and Technology, Beijing, 100190 China
| | - YongQing Fu
- Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST United Kingdom
| | - Huigao Duan
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 China
- Greater Bay Area Institute for Innovation, Hunan University, Guangzhou, 511300 Guangdong Province China
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10
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Lan L, Ping J, Xiong J, Ying Y. Sustainable Natural Bio-Origin Materials for Future Flexible Devices. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200560. [PMID: 35322600 PMCID: PMC9130888 DOI: 10.1002/advs.202200560] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/27/2022] [Indexed: 05/12/2023]
Abstract
Flexible devices serve as important intelligent interfaces in various applications involving health monitoring, biomedical therapies, and human-machine interfacing. To address the concern of electronic waste caused by the increasing usage of electronic devices based on synthetic polymers, bio-origin materials that possess environmental benignity as well as sustainability offer new opportunities for constructing flexible electronic devices with higher safety and environmental adaptivity. Herein, the bio-source and unique molecular structures of various types of natural bio-origin materials are briefly introduced. Their properties and processing technologies are systematically summarized. Then, the recent progress of these materials for constructing emerging intelligent flexible electronic devices including energy harvesters, energy storage devices, and sensors are introduced. Furthermore, the applications of these flexible electronic devices including biomedical implants, artificial e-skin, and environmental monitoring are summarized. Finally, future challenges and prospects for developing high-performance bio-origin material-based flexible devices are discussed. This review aims to provide a comprehensive and systematic summary of the latest advances in the natural bio-origin material-based flexible devices, which is expected to offer inspirations for exploitation of green flexible electronics, bridging the gap in future human-machine-environment interactions.
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Affiliation(s)
- Lingyi Lan
- Laboratory of Agricultural Information Intelligent SensingSchool of Biosystems Engineering and Food ScienceZhejiang UniversityHangzhouZhejiang310058China
- Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang ProvinceHangzhouZhejiang310058China
| | - Jianfeng Ping
- Laboratory of Agricultural Information Intelligent SensingSchool of Biosystems Engineering and Food ScienceZhejiang UniversityHangzhouZhejiang310058China
- Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang ProvinceHangzhouZhejiang310058China
| | - Jiaqing Xiong
- Innovation Center for Textile Science and TechnologyDonghua University2999 North Renmin RoadShanghai201620China
| | - Yibin Ying
- Laboratory of Agricultural Information Intelligent SensingSchool of Biosystems Engineering and Food ScienceZhejiang UniversityHangzhouZhejiang310058China
- Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang ProvinceHangzhouZhejiang310058China
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11
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Xiang W, Xie Y, Han Y, Long Z, Zhang W, Zhong T, Liang S, Xing L, Xue X, Zhan Y. A self-powered wearable brain-machine-interface system for ceasing action. NANOSCALE 2022; 14:4671-4678. [PMID: 35262127 DOI: 10.1039/d1nr08168c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A self-powered wearable brain-machine-interface system with pulse detection and brain stimulation for ceasing action has been realized. The system is composed of (1) a power supply unit that employs a piezoelectric generator and converts the mechanical energy of human daily activities into electricity; (2) a neck pulse biosensor that allows continuous measurements of carotid pulse by using a piezoelectric polyvinylidene fluoride film; (3) a data analysis module that enables a coordinated brain-machine-interface system to output brain stimulation signals; and (4) brain stimulating electrodes linked to the brain that implement behavioral intervention. Demonstration of the system with stimulating electrodes implanted in the periaqueductal gray (PAG) in running mice reveals the great effect of forced ceasing action. The mice stop their running within several seconds when the stimulation signals are sent into the PAG brain region (inducing fear). This self-powered scheme for neural stimulation realizes specific behavioral intervention without any external power supply, thus providing a new concept for future behavior intervention.
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Affiliation(s)
- Wang Xiang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Yan Xie
- Department of Neurology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 610072, China
| | - Yechao Han
- CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
| | - Zhihe Long
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Wanglinhan Zhang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Tianyan Zhong
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Shan Liang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Lili Xing
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Xinyu Xue
- School of Physics, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Yang Zhan
- CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
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12
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Zeng X, Deng HT, Wen DL, Li YY, Xu L, Zhang XS. Wearable Multi-Functional Sensing Technology for Healthcare Smart Detection. MICROMACHINES 2022; 13:mi13020254. [PMID: 35208378 PMCID: PMC8874439 DOI: 10.3390/mi13020254] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 11/21/2022]
Abstract
In recent years, considerable research efforts have been devoted to the development of wearable multi-functional sensing technology to fulfill the requirements of healthcare smart detection, and much progress has been achieved. Due to the appealing characteristics of flexibility, stretchability and long-term stability, the sensors have been used in a wide range of applications, such as respiration monitoring, pulse wave detection, gait pattern analysis, etc. Wearable sensors based on single mechanisms are usually capable of sensing only one physiological or motion signal. In order to measure, record and analyze comprehensive physical conditions, it is indispensable to explore the wearable sensors based on hybrid mechanisms and realize the integration of multiple smart functions. Herein, we have summarized various working mechanisms (resistive, capacitive, triboelectric, piezoelectric, thermo-electric, pyroelectric) and hybrid mechanisms that are incorporated into wearable sensors. More importantly, to make wearable sensors work persistently, it is meaningful to combine flexible power units and wearable sensors and form a self-powered system. This article also emphasizes the utility of self-powered wearable sensors from the perspective of mechanisms, and gives applications. Furthermore, we discuss the emerging materials and structures that are applied to achieve high sensitivity. In the end, we present perspectives on the outlooks of wearable multi-functional sensing technology.
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Affiliation(s)
- Xu Zeng
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; (X.Z.); (H.-T.D.); (D.-L.W.); (Y.-Y.L.)
| | - Hai-Tao Deng
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; (X.Z.); (H.-T.D.); (D.-L.W.); (Y.-Y.L.)
| | - Dan-Liang Wen
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; (X.Z.); (H.-T.D.); (D.-L.W.); (Y.-Y.L.)
| | - Yao-Yao Li
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; (X.Z.); (H.-T.D.); (D.-L.W.); (Y.-Y.L.)
| | - Li Xu
- Rehabilitation Department, Sichuan Provincial People’s Hospital, Chengdu 610072, China
- Correspondence: (L.X.); (X.-S.Z.)
| | - Xiao-Sheng Zhang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; (X.Z.); (H.-T.D.); (D.-L.W.); (Y.-Y.L.)
- Correspondence: (L.X.); (X.-S.Z.)
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13
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Mirjalali S, Peng S, Fang Z, Wang C, Wu S. Wearable Sensors for Remote Health Monitoring: Potential Applications for Early Diagnosis of Covid-19. ADVANCED MATERIALS TECHNOLOGIES 2022; 7:2100545. [PMID: 34901382 PMCID: PMC8646515 DOI: 10.1002/admt.202100545] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/22/2021] [Indexed: 05/11/2023]
Abstract
Wearable sensors are emerging as a new technology to detect physiological and biochemical markers for remote health monitoring. By measuring vital signs such as respiratory rate, body temperature, and blood oxygen level, wearable sensors offer tremendous potential for the noninvasive and early diagnosis of numerous diseases such as Covid-19. Over the past decade, significant progress has been made to develop wearable sensors with high sensitivity, accuracy, flexibility, and stretchability, bringing to reality a new paradigm of remote health monitoring. In this review paper, the latest advances in wearable sensor systems that can measure vital signs at an accuracy level matching those of point-of-care tests are presented. In particular, the focus of this review is placed on wearable sensors for measuring respiratory behavior, body temperature, and blood oxygen level, which are identified as the critical signals for diagnosing and monitoring Covid-19. Various designs based on different materials and working mechanisms are summarized. This review is concluded by identifying the remaining challenges and future opportunities for this emerging field.
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Affiliation(s)
- Sheyda Mirjalali
- School of EngineeringMacquarie University SydneySydneyNSW2109Australia
| | - Shuhua Peng
- School of Mechanical and Manufacturing EngineeringUniversity of New South WalesSydneyNSW2052Australia
| | | | - Chun‐Hui Wang
- School of Mechanical and Manufacturing EngineeringUniversity of New South WalesSydneyNSW2052Australia
| | - Shuying Wu
- School of EngineeringMacquarie University SydneySydneyNSW2109Australia
- School of Mechanical and Manufacturing EngineeringUniversity of New South WalesSydneyNSW2052Australia
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14
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Qureshi S, Stojanović GM, Simić M, Jeoti V, Lashari N, Sher F. Silver Conductive Threads-Based Embroidered Electrodes on Textiles as Moisture Sensors for Fluid Detection in Biomedical Applications. MATERIALS (BASEL, SWITZERLAND) 2021; 14:7813. [PMID: 34947407 PMCID: PMC8707788 DOI: 10.3390/ma14247813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 01/03/2023]
Abstract
Wearable sensors have become part of our daily life for health monitoring. The detection of moisture content is critical for many applications. In the present research, textile-based embroidered sensors were developed that can be integrated with a bandage for wound management purposes. The sensor comprised an interdigitated electrode embroidered on a cotton substrate with silver-tech 150 and HC 12 threads, respectively, that have silver coated continuous filaments and 100% polyamide with silver-plated yarn. The said sensor is a capacitive sensor with some leakage. The change in the dielectric constant of the substrate as a result of moisture affects the value of capacitance and, thus, the admittance of the sensor. The moisture sensor's operation is verified by measuring its admittance at 1 MHz and the change in moisture level (1-50) µL. It is observed that the sensitivity of both sensors is comparable. The identically fabricated sensors show similar response and sensitivity while wash test shows the stability of sensor after washing. The developed sensor is also able to detect the moisture caused by both artificial sweat and blood serum, which will be of value in developing new sensors tomorrow for smart wound-dressing applications.
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Affiliation(s)
- Saima Qureshi
- Faculty of Technical Sciences, University of Novi Sad, T. Dositeja Obradovića 6, 21000 Novi Sad, Serbia; (G.M.S.); (M.S.); (V.J.)
| | - Goran M. Stojanović
- Faculty of Technical Sciences, University of Novi Sad, T. Dositeja Obradovića 6, 21000 Novi Sad, Serbia; (G.M.S.); (M.S.); (V.J.)
| | - Mitar Simić
- Faculty of Technical Sciences, University of Novi Sad, T. Dositeja Obradovića 6, 21000 Novi Sad, Serbia; (G.M.S.); (M.S.); (V.J.)
| | - Varun Jeoti
- Faculty of Technical Sciences, University of Novi Sad, T. Dositeja Obradovića 6, 21000 Novi Sad, Serbia; (G.M.S.); (M.S.); (V.J.)
| | - Najeebullah Lashari
- Department of Petroleum Engineering, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak Darul Ridzuan, Malaysia;
| | - Farooq Sher
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK
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15
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Kim J, Jung H, Kim M, Bae H, Lee Y. Conductive Polymer Composites for Soft Tactile Sensors. Macromol Res 2021. [DOI: 10.1007/s13233-021-9092-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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He W, Ye X, Cui T. Progress of shrink polymer micro- and nanomanufacturing. MICROSYSTEMS & NANOENGINEERING 2021; 7:88. [PMID: 34790360 PMCID: PMC8566528 DOI: 10.1038/s41378-021-00312-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/29/2021] [Accepted: 09/16/2021] [Indexed: 05/31/2023]
Abstract
Traditional lithography plays a significant role in the fabrication of micro- and nanostructures. Nevertheless, the fabrication process still suffers from the limitations of manufacturing devices with a high aspect ratio or three-dimensional structure. Recent findings have revealed that shrink polymers attain a certain potential in micro- and nanostructure manufacturing. This technique, denoted as heat-induced shrink lithography, exhibits inherent merits, including an improved fabrication resolution by shrinking, controllable shrinkage behavior, and surface wrinkles, and an efficient fabrication process. These merits unfold new avenues, compensating for the shortcomings of traditional technologies. Manufacturing using shrink polymers is investigated in regard to its mechanism and applications. This review classifies typical applications of shrink polymers in micro- and nanostructures into the size-contraction feature and surface wrinkles. Additionally, corresponding shrinkage mechanisms and models for shrinkage, and wrinkle parameter control are examined. Regarding the size-contraction feature, this paper summarizes the progress on high-aspect-ratio devices, microchannels, self-folding structures, optical antenna arrays, and nanowires. Regarding surface wrinkles, this paper evaluates the development of wearable sensors, electrochemical sensors, energy-conversion technology, cell-alignment structures, and antibacterial surfaces. Finally, the limitations and prospects of shrink lithography are analyzed.
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Affiliation(s)
- Wenzheng He
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, 100084 China
| | - Xiongying Ye
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, 100084 China
| | - Tianhong Cui
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street S.E., Minneapolis, MN 55455 USA
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17
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Chen G, Zhao X, Andalib S, Xu J, Zhou Y, Tat T, Lin K, Chen J. Discovering giant magnetoelasticity in soft matter for electronic textiles. MATTER 2021; 4:3725-3740. [PMID: 35846392 PMCID: PMC9281417 DOI: 10.1016/j.matt.2021.09.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We discovered a giant magnetoelasticity in soft matter with up to 5-fold enhancement of magnetomechanical coupling factors compared to that of rigid metal alloys without an externally applied magnetic field. A wavy chain analytical model based on the magnetic dipole-dipole interaction and demagnetizing field was established, fitting well to the experimental observation. To explore its potentials in electronic textiles, we coupled it with magnetic induction to invent a textile magnetoelastic generator (MEG), a new working mechanism for biomechanical energy conversion, featuring an intrinsic waterproofness, an ultralow internal impedance of approximately 20 Ω, and a high short-circuit current density of 1.37 mA/cm2, which is about four orders of magnitude higher than that of other textile generator counterparts. Meanwhile, assisted by machine learning, the textile MEG could continuously monitor the respiratory activities on heavily perspiring skin without any encapsulation, allowing a timely diagnosis of the respiration abnormalities in a self-powered manner. We foresee that this discovery can be extended to wide-range soft-matter systems, emerging as a compelling approach to develop electronic textiles for energy, sensing, and therapeutic applications.
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Affiliation(s)
- Guorui Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- These authors contributed equally
| | - Xun Zhao
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- These authors contributed equally
| | - Sahar Andalib
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jing Xu
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yihao Zhou
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Trinny Tat
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ke Lin
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jun Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Lead contact
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18
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An Overview of Wearable Piezoresistive and Inertial Sensors for Respiration Rate Monitoring. ELECTRONICS 2021. [DOI: 10.3390/electronics10172178] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The demand for wearable devices to measure respiratory activity is constantly growing, finding applications in a wide range of scenarios (e.g., clinical environments and workplaces, outdoors for monitoring sports activities, etc.). Particularly, the respiration rate (RR) is a vital parameter since it indicates serious illness (e.g., pneumonia, emphysema, pulmonary embolism, etc.). Therefore, several solutions have been presented in the scientific literature and on the market to make RR monitoring simple, accurate, reliable and noninvasive. Among the different transduction methods, the piezoresistive and inertial ones satisfactorily meet the requirements for smart wearable devices since unobtrusive, lightweight and easy to integrate. Hence, this review paper focuses on innovative wearable devices, detection strategies and algorithms that exploit piezoresistive or inertial sensors to monitor the breathing parameters. At first, this paper presents a comprehensive overview of innovative piezoresistive wearable devices for measuring user’s respiratory variables. Later, a survey of novel piezoresistive textiles to develop wearable devices for detecting breathing movements is reported. Afterwards, the state-of-art about wearable devices to monitor the respiratory parameters, based on inertial sensors (i.e., accelerometers and gyroscopes), is presented for detecting dysfunctions or pathologies in a non-invasive and accurate way. In this field, several processing tools are employed to extract the respiratory parameters from inertial data; therefore, an overview of algorithms and methods to determine the respiratory rate from acceleration data is provided. Finally, comparative analysis for all the covered topics are reported, providing useful insights to develop the next generation of wearable sensors for monitoring respiratory parameters.
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19
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Wang M, Mu L, Zhang H, Ma S, Liang Y, Ren L. Flexible strain sensor with ridge‐like microstructures for wearable applications. POLYM ADVAN TECHNOL 2021. [DOI: 10.1002/pat.5493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Meng Wang
- The Key Laboratory of Bionic Engineering, Ministry of Education Jilin University Changchun China
- Center of Reproductive Medicine, Center of Prenatal Diagnosis The First Hospital of Jilin University, Jilin University Changchun China
| | - Lin Mu
- Department of Radiology The First Hospital of Jilin University, Jilin University Changchun China
| | - Hao Zhang
- The Key Laboratory of Bionic Engineering, Ministry of Education Jilin University Changchun China
| | - Suqian Ma
- The Key Laboratory of Bionic Engineering, Ministry of Education Jilin University Changchun China
| | - Yunhong Liang
- The Key Laboratory of Bionic Engineering, Ministry of Education Jilin University Changchun China
| | - Lei Ren
- The Key Laboratory of Bionic Engineering, Ministry of Education Jilin University Changchun China
- Department of Mechanical, Aerospace and Civil Engineering University of Manchester Manchester UK
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20
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Highly Stretchable and Kirigami-Structured Strain Sensors with Long Silver Nanowires of High Aspect Ratio. MACHINES 2021. [DOI: 10.3390/machines9090186] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Stretchable, skin-interfaced, and wearable strain sensors have risen in recent years due to their wide-ranging potential applications in health-monitoring devices, human motion detection, and soft robots. High aspect ratio (AR) silver nanowires (AgNWs) have shown great potential in the flexible and stretchable strain sensors due to the high conductivity and flexibility of AgNW conductive networks. Hence, this work aims to fabricate highly stretchable, sensitive, and linear kirigami strain sensors with high AR AgNWs. The AgNW synthesis parameters and process windows have been identified by Taguchi’s design of experiment and analysis. Long AgNWs with a high AR of 1556 have been grown at optimized synthesis parameters using the one-pot modified polyol method. Kirigami sensors were fabricated via full encapsulation of AgNWs with Ecoflex silicon rubber. Kirigami-patterned strain sensors with long AgNWs show high stretchability, moderate sensitivity, excellent linearity (R2 = 0.99) up to 70% strain and can promptly detect finger movement without obvious hysteresis.
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21
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Persons AK, Ball JE, Freeman C, Macias DM, Simpson CL, Smith BK, Burch V. RF. Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4070. [PMID: 34361264 PMCID: PMC8347841 DOI: 10.3390/ma14154070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/09/2021] [Accepted: 07/16/2021] [Indexed: 12/23/2022]
Abstract
Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from "bench to bedside", fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.
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Affiliation(s)
- Andrea Karen Persons
- Department of Agricultural and Biological Engineering, Mississippi State University, 130 Creelman Street, Starkville, MS 39762, USA; (A.K.P.); (C.L.S.)
- Human Factors and Athlete Engineering, Center for Advanced Vehicular Systems, Mississippi State University, 200 Research Boulevard, Starkville, MS 39759, USA;
| | - John E. Ball
- Human Factors and Athlete Engineering, Center for Advanced Vehicular Systems, Mississippi State University, 200 Research Boulevard, Starkville, MS 39759, USA;
- Department of Electrical and Computer Engineering, Mississippi State University, 406 Hardy Road, Starkville, MS 39762, USA
| | - Charles Freeman
- School of Human Sciences, Mississippi State University, 255 Tracy Drive, Starkville, MS 39762, USA;
| | - David M. Macias
- Department of Kinesiology, Mississippi State University, P.O. Box 6186, Starkville, MS 39762, USA;
- Columbus Orthopaedic Clinic, 670 Leigh Drive, Columbus, MS 39705, USA
| | - Chartrisa LaShan Simpson
- Department of Agricultural and Biological Engineering, Mississippi State University, 130 Creelman Street, Starkville, MS 39762, USA; (A.K.P.); (C.L.S.)
| | - Brian K. Smith
- Department of Industrial and Systems Engineering, Mississippi State University, 479-2 Hardy Road, Starkville, MS 39762, USA;
| | - Reuben F. Burch V.
- Human Factors and Athlete Engineering, Center for Advanced Vehicular Systems, Mississippi State University, 200 Research Boulevard, Starkville, MS 39759, USA;
- Department of Industrial and Systems Engineering, Mississippi State University, 479-2 Hardy Road, Starkville, MS 39762, USA;
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22
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Wang M, Li W, Tang G, Garciamendez-Mijares CE, Zhang YS. Engineering (Bio)Materials through Shrinkage and Expansion. Adv Healthc Mater 2021; 10:e2100380. [PMID: 34137213 PMCID: PMC8295236 DOI: 10.1002/adhm.202100380] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/27/2021] [Indexed: 12/12/2022]
Abstract
Although various (bio)fabrication technologies have achieved revolutionary progress in the past decades, engineered constructs still fall short of expectations owing to their inability to attain precisely designable functions. Shrinkable and expandable (bio)materials feature unique characteristics leading to size-/shape-shifting and thus have exhibited a strong potential to equip current engineering technologies with promoted capacities toward applications in biomedicine. In this progress report, the advances of size-/shape-shifting (bio)materials enabled by various stimuli, are evaluated; furthermore, representative biomedical applications associated with size-/shape-shifting (bio)materials are also exemplified. Toward the future, the combination of size-/shape-shifting (bio)materials and 3D/4D fabrication technologies presents a wide range of possibilities for further development of intricate functional architectures.
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Affiliation(s)
- Mian Wang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Wanlu Li
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Guosheng Tang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Carlos Ezio Garciamendez-Mijares
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
| | - Yu Shrike Zhang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, 02139, USA
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23
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The Effect of Encapsulation on Crack-Based Wrinkled Thin Film Soft Strain Sensors. MATERIALS 2021; 14:ma14020364. [PMID: 33450998 PMCID: PMC7828450 DOI: 10.3390/ma14020364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 12/15/2022]
Abstract
Practical wearable applications of soft strain sensors require sensors capable of not only detecting subtle physiological signals, but also of withstanding large scale deformation from body movement. Encapsulation is one technique to protect sensors from both environmental and mechanical stressors. We introduced an encapsulation layer to crack-based wrinkled metallic thin film soft strain sensors as an avenue to improve sensor stretchability, linear response, and robustness. We demonstrate that encapsulated sensors have increased mechanical robustness and stability, displaying a significantly larger linear dynamic range (~50%) and increased stretchability (260% elongation). Furthermore, we discovered that these sensors have post-fracture signal recovery. They maintained conductivity to the 50% strain with stable signal and demonstrated increased sensitivity. We studied the crack formation behind this phenomenon and found encapsulation to lead to higher crack density as the source for greater stretchability. As crack formation plays an important role in subsequent electrical resistance, understanding the crack evolution in our sensors will help us better address the trade-off between high stretchability and high sensitivity.
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24
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Zhou Y, Werner EM, Lee E, Chu M, Nguyen T, Costa KD, Hui EE, Khine M. High-resolution integrated piezoresistive sensors for microfluidic monitoring. LAB ON A CHIP 2021; 21:83-92. [PMID: 33300516 PMCID: PMC9521707 DOI: 10.1039/d0lc01046d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Microfluidic devices are traditionally monitored by bulky and expensive off-chip sensors. We have developed a soft piezoresistive sensor capable of measuring micron-level strains that can be easily integrated into devices via soft lithography. We apply this sensor to achieve fast and localized monitoring of pressure, flow, and valve actuation.
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Affiliation(s)
- Yongxiao Zhou
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA.
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25
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Inkjet Printing of Highly Sensitive, Transparent, Flexible Linear Piezoresistive Strain Sensors. COATINGS 2021. [DOI: 10.3390/coatings11010051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flexible strain sensors are fabricated by using a simple and low-cost inkjet printing technology of graphene-PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)) conductive ink. The inkjet-printed thin-film resistors on a polyethylene terephthalate (PET) substrate exhibit an excellent optical transmittance of about 90% over a visible wavelength range from 400 to 800 nm. While an external mechanical strain is applied to thin-film resistors as strain sensors, a gauge factor (GF) of the piezoresistive (PR) strain sensors can be evaluated. To improve the GF value of the PR strain sensors, a high resistive (HR) path caused by the phase segregation of the PEDOT:PSS polymer material is, for the first time, proposed to be perpendicular to the PR strain sensing direction. The increase in the GF with the increase in the HR number of the PR strain sensors without a marked hysteresis is found. The result can be explained by the tunneling effect with varied initial tunneling distances and tunneling barriers due to the increase in the number of HR. Finally, a high GF value of approximately 165 of three HR paths is obtained with a linear output signal at the strain range from 0% to 0.33%, further achieving for the inkjet printing of highly sensitive, transparent, and flexible linear PR strain sensors.
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26
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Electrically conductive NBR/CB flexible composite film for ultrastretchable strain sensors: fabrication and modeling. APPLIED NANOSCIENCE 2021. [DOI: 10.1007/s13204-020-01619-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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27
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Zhao Z, Yuan X, Huang Y, Wang J. CNT-Br/PEDOT:PSS/PAAS three-network composite conductive hydrogel for human motion monitoring. NEW J CHEM 2021. [DOI: 10.1039/d0nj04867d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Conductive hydrogels are promising flexible conductors for human motion monitoring.
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Affiliation(s)
- Zhonghua Zhao
- Shanghai Key Laboratory of Advanced Polymeric Materials
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
- Shanghai
| | - Xiang Yuan
- Shanghai Key Laboratory of Advanced Polymeric Materials
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
- Shanghai
| | - Yicheng Huang
- Shanghai Key Laboratory of Advanced Polymeric Materials
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
- Shanghai
| | - Jikui Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials
- Key Laboratory for Ultrafine Materials of Ministry of Education
- School of Materials Science and Engineering
- East China University of Science and Technology
- Shanghai
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28
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Silva AF, Tavakoli M. Domiciliary Hospitalization through Wearable Biomonitoring Patches: Recent Advances, Technical Challenges, and the Relation to Covid-19. SENSORS (BASEL, SWITZERLAND) 2020; 20:E6835. [PMID: 33260466 PMCID: PMC7729497 DOI: 10.3390/s20236835] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/10/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022]
Abstract
This article reviews recent advances and existing challenges for the application of wearable bioelectronics for patient monitoring and domiciliary hospitalization. More specifically, we focus on technical challenges and solutions for the implementation of wearable and conformal bioelectronics for long-term patient biomonitoring and discuss their application on the Internet of medical things (IoMT). We first discuss the general architecture of IoMT systems for domiciliary hospitalization and the three layers of the system, including the sensing, communication, and application layers. In regard to the sensing layer, we focus on current trends, recent advances, and challenges in the implementation of stretchable patches. This includes fabrication strategies and solutions for energy storage and energy harvesting, such as printed batteries and supercapacitors. As a case study, we discuss the application of IoMT for domiciliary hospitalization of COVID 19 patients. This can be used as a strategy to reduce the pressure on the healthcare system, as it allows continuous patient monitoring and reduced physical presence in the hospital, and at the same time enables the collection of large data for posterior analysis. Finally, based on the previous works in the field, we recommend a conceptual IoMT design for wearable monitoring of COVID 19 patients.
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Affiliation(s)
| | - Mahmoud Tavakoli
- Institute of Systems and Robotics, Department of Electrical Engineering, University of Coimbra, 3030-290 Coimbra, Portugal;
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Abstract
Chemometrics play a critical role in biosensors-based detection, analysis, and diagnosis. Nowadays, as a branch of artificial intelligence (AI), machine learning (ML) have achieved impressive advances. However, novel advanced ML methods, especially deep learning, which is famous for image analysis, facial recognition, and speech recognition, has remained relatively elusive to the biosensor community. Herein, how ML can be beneficial to biosensors is systematically discussed. The advantages and drawbacks of most popular ML algorithms are summarized on the basis of sensing data analysis. Specially, deep learning methods such as convolutional neural network (CNN) and recurrent neural network (RNN) are emphasized. Diverse ML-assisted electrochemical biosensors, wearable electronics, SERS and other spectra-based biosensors, fluorescence biosensors and colorimetric biosensors are comprehensively discussed. Furthermore, biosensor networks and multibiosensor data fusion are introduced. This review will nicely bridge ML with biosensors, and greatly expand chemometrics for detection, analysis, and diagnosis.
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Affiliation(s)
- Feiyun Cui
- Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, United States
| | - Yun Yue
- Department of Electrical & Computer Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States
| | - Yi Zhang
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Ziming Zhang
- Department of Electrical & Computer Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States
| | - H. Susan Zhou
- Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, United States
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Qu M, Qin Y, Sun Y, Xu H, Schubert DW, Zheng K, Xu W, Nilsson F. Biocompatible, Flexible Strain Sensor Fabricated with Polydopamine-Coated Nanocomposites of Nitrile Rubber and Carbon Black. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42140-42152. [PMID: 32816448 DOI: 10.1021/acsami.0c11937] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A flexible, biocompatible, nitrile butadiene rubber (NBR)-based strain sensor with high stretchability, good sensitivity, and excellent repeatability is presented for the first time. Carbon black (CB) particles were embedded into an NBR matrix via a dissolving-coating technique, and the obtained NBR/CB composite was coated with polydopamine (PDA) to preserve the CB layer. The mechanical properties of the NBR films were found to be significantly improved with the addition of CB and PDA, and the produced composite films were noncytotoxic and highly biocompatible. Strain-sensing tests showed that the uncoated CB/NBR films possess a high sensing range (strain of ∼550%) and good sensitivity (gauge factor of 52.2), whereas the PDA/NBR/CB films show a somewhat reduced sensing range (strain of ∼180%) but significantly improved sensitivity (gauge factor of 346). The hysteresis curves obtained from cyclic strain-sensing tests demonstrate the prominent robustness of the sensor material. Three novel equations were developed to accurately describe the uniaxial and cyclic strain-sensing behavior observed for the investigated strain sensors. Gloves and knee/elbow covers were produced from the films, revealing that the signals generated by different finger, elbow, and knee movements are easily distinguishable, thus confirming that the PDA/NBR/CB composite films can be used in a wide range of wearable strain sensor applications.
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Affiliation(s)
- Muchao Qu
- School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, 510450 Guangzhou, China
- Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany
| | - Yijing Qin
- Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany
| | - Yue Sun
- Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany
| | - Huagen Xu
- Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany
| | - Dirk W Schubert
- Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany
| | - Kai Zheng
- Institute of Biomaterials, Friedrich-Alexander-University Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen, Germany
| | - Wei Xu
- School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, 510450 Guangzhou, China
| | - Fritjof Nilsson
- School of Chemical Science and Engineering, Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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31
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Nakajima T, Tsuchiya T. Ultrathin Highly Flexible Featherweight Ceramic Temperature Sensor Arrays. ACS APPLIED MATERIALS & INTERFACES 2020; 12:36600-36608. [PMID: 32805791 DOI: 10.1021/acsami.0c08718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We fabricated highly flexible Sr- and Ni-doped perovskite SmMnO3 thermistor film sensor arrays on an ultrathin (5 μm thick) and lightweight (21 mg) polyimide sheet for healthcare monitoring devices. The Ag nanowire and nanoparticle-impregnated carbon microcone array, which was prepared by precisely controlled surface laser carbonization of polyimide, showed sufficiently low resistance as a bottom electrode and good stability against sharp bending angles. The dot-shaped (diameter: 900 μm) perovskite thermistor film with a thickness of 900 nm was crystallized by pulsed ultraviolet laser irradiation of a precursor film printed with perovskite nanoparticle dispersion ink, and the film functioned well as the thermistor with a thermistor constant of 2820 K. The thermistor sensor sheet exhibited rapid responses to temperature variation and high stability in the temperature cycle tests over 1000 cycles between room temperature and 80 °C. The bending durability for a bending angle of 60° with a small bending radius (500 μm) was also high. During the bending test over 1000 cycles, the monitoring temperature variation was suppressed only within 0.1 °C. This ultrathin sensor array sheet can be mounted on surfaces with shape variations, and we used the sensor for real-time monitoring in healthcare to detect precise temperature variations on the human skin during physical exercise.
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Affiliation(s)
- Tomohiko Nakajima
- Advanced Coating Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Tetsuo Tsuchiya
- Advanced Coating Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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Dinh T, Nguyen T, Phan HP, Nguyen NT, Dao DV, Bell J. Stretchable respiration sensors: Advanced designs and multifunctional platforms for wearable physiological monitoring. Biosens Bioelectron 2020; 166:112460. [PMID: 32862846 DOI: 10.1016/j.bios.2020.112460] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/21/2022]
Abstract
Respiration signals are a vital sign of life. Monitoring human breath provides critical information for health assessment, diagnosis, and treatment for respiratory diseases such as asthma, chronic bronchitis, and emphysema. Stretchable and wearable respiration sensors have recently attracted considerable interest toward monitoring physiological signals in the era of real time and portable healthcare systems. This review provides a snapshot on the recent development of stretchable sensors and wearable technologies for respiration monitoring. The article offers the fundamental guideline on the sensing mechanisms and design concepts of stretchable sensors for detecting vital breath signals such as temperature, humidity, airflow, stress and strain. A highlight on the recent progress in the integration of variable sensing components outlines feasible pathways towards multifunctional and multimodal sensor platforms. Structural designs of nanomaterials and platforms for stretchable respiration sensors are reviewed.
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Affiliation(s)
- Toan Dinh
- School of Mechanical and Electrical Engineering, University of Southern Queensland, Queensland, 4350, Australia.
| | - Thanh Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, Queensland, 4111, Australia
| | - Hoang-Phuong Phan
- Queensland Micro- and Nanotechnology Centre, Griffith University, Queensland, 4111, Australia
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, Queensland, 4111, Australia
| | - Dzung Viet Dao
- Queensland Micro- and Nanotechnology Centre, Griffith University, Queensland, 4111, Australia
| | - John Bell
- School of Mechanical and Electrical Engineering, University of Southern Queensland, Queensland, 4350, Australia
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Challenges in Design and Fabrication of Flexible/Stretchable Carbon- and Textile-Based Wearable Sensors for Health Monitoring: A Critical Review. SENSORS 2020; 20:s20143927. [PMID: 32679666 PMCID: PMC7412463 DOI: 10.3390/s20143927] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/29/2020] [Accepted: 07/09/2020] [Indexed: 01/01/2023]
Abstract
To demonstrate the wearable flexible/stretchable health-monitoring sensor, it is necessary to develop advanced functional materials and fabrication technologies. Among the various developed materials and fabrication processes for wearable sensors, carbon-based materials and textile-based configurations are considered as promising approaches due to their outstanding characteristics such as high conductivity, lightweight, high mechanical properties, wearability, and biocompatibility. Despite these advantages, in order to realize practical wearable applications, electrical and mechanical performances such as sensitivity, stability, and long-term use are still not satisfied. Accordingly, in this review, we describe recent advances in process technologies to fabricate advanced carbon-based materials and textile-based sensors, followed by their applications such as human activity and electrophysiological sensors. Furthermore, we discuss the remaining challenges for both carbon- and textile-based wearable sensors and then suggest effective strategies to realize the wearable sensors in health monitoring.
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Nguyen T, Khine M. Advances in Materials for Soft Stretchable Conductors and Their Behavior under Mechanical Deformation. Polymers (Basel) 2020; 12:E1454. [PMID: 32610500 PMCID: PMC7408380 DOI: 10.3390/polym12071454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/26/2020] [Accepted: 06/19/2020] [Indexed: 12/28/2022] Open
Abstract
Soft stretchable sensors rely on polymers that not only withstand large deformations while retaining functionality but also allow for ease of application to couple with the body to capture subtle physiological signals. They have been applied towards motion detection and healthcare monitoring and can be integrated into multifunctional sensing platforms for enhanced human machine interface. Most advances in sensor development, however, have been aimed towards active materials where nearly all approaches rely on a silicone-based substrate for mechanical stability and stretchability. While silicone use has been advantageous in academic settings, conventional silicones cannot offer self-healing capability and can suffer from manufacturing limitations. This review aims to cover recent advances made in polymer materials for soft stretchable conductors. New developments in substrate materials that are compliant and stretchable but also contain self-healing properties and self-adhesive capabilities are desirable for the mechanical improvement of stretchable electronics. We focus on materials for stretchable conductors and explore how mechanical deformation impacts their performance, summarizing active and substrate materials, sensor performance criteria, and applications.
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Affiliation(s)
- Thao Nguyen
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA 92697, USA;
| | - Michelle Khine
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA 92697, USA;
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA
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35
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Herbert R, Lim HR, Yeo WH. Printed, Soft, Nanostructured Strain Sensors for Monitoring of Structural Health and Human Physiology. ACS APPLIED MATERIALS & INTERFACES 2020; 12:25020-25030. [PMID: 32393022 DOI: 10.1021/acsami.0c04857] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Soft strain sensors that are mechanically flexible or stretchable are of significant interest in the fields of structural health monitoring, human physiology, and human-machine interfaces. However, existing deformable strain sensors still suffer from complex fabrication processes, poor reusability, limited adhesion strength, or structural rigidity. In this work, we introduce a versatile, high-throughput fabrication method of nanostructured, soft material-enabled, miniaturized strain sensors for both structural health monitoring and human physiology detection. Aerosol jet printing of polyimide and silver nanowires enables multifunctional strain sensors with tunable resistance and gauge factor. Experimental study of soft material compositions and multilayered structures of the strain sensor demonstrates the capabilities of strong adhesion and conformal lamination on different surfaces without the use of conventional fixtures and/or tapes. A two-axis, printed strain gauge enables the detection of force-induced strain changes on a curved stem valve for structural health management while offering reusability over 10 times without losing the sensing performance. Direct comparison with a commercial film sensor captures the advantages of the printed soft sensor in enhanced gauge factor and sensitivity. Another type of a stretchable strain sensor in skin-wearable applications demonstrates a highly sensitive monitoring of a subject's motion, pulse, and breathing, validated by comparing it with a clinical-grade system. Overall, the presented comprehensive study of materials, mechanics, printing-based fabrication, and interfacial adhesion shows a great potential of the printed soft strain sensor for applications in continuous structural health monitoring, human health detection, machine-interfacing systems, and environmental condition monitoring.
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Affiliation(s)
- Robert Herbert
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Hyo-Ryoung Lim
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Woon-Hong Yeo
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Parker H. Petit Institute for Bioengineering and Biosciences, Neural Engineering Center, Institute for Materials, Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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36
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Dallinger A, Keller K, Fitzek H, Greco F. Stretchable and Skin-Conformable Conductors Based on Polyurethane/Laser-Induced Graphene. ACS APPLIED MATERIALS & INTERFACES 2020; 12:19855-19865. [PMID: 32249561 PMCID: PMC7304821 DOI: 10.1021/acsami.0c03148] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/06/2020] [Indexed: 05/18/2023]
Abstract
The conversion of various polymer substrates into laser-induced graphene (LIG) with a CO2 laser in ambient condition is recently emerging as a simple method for obtaining patterned porous graphene conductors, with a myriad of applications in sensing, actuation, and energy. In this paper, a method is presented for embedding porous LIG (LIG-P) or LIG fibers (LIG-F) into a thin (about 50 μm) and soft medical grade polyurethane (MPU) providing excellent conformal adhesion on skin, stretchability, and maximum breathability to boost the development of various unperceivable monitoring systems on skin. The effect of varying laser fluence and geometry of the laser scribing on the LIG micro-nanostructure morphology and on the electrical and electromechanical properties of LIG/MPU composites is investigated. A peculiar and distinct behavior is observed for either LIG-P or LIG-F. Excellent stretchability without permanent impairment of conductive properties is revealed up to 100% strain and retained after hundreds of cycles of stretching tests. A distinct piezoresistive behavior, with an average gauge factor of 40, opens the way to various potential strain/pressure sensing applications. A novel method based on laser scribing is then introduced for providing vertical interconnect access (VIA) into LIG/MPU conformable epidermal sensors. Such VIA enables stable connections to an external measurement device, as this represents a typical weakness of many epidermal devices so far. Three examples of minimally invasive LIG/MPU epidermal sensing proof of concepts are presented: as electrodes for electromyographic recording on limb and as piezoresistive sensors for touch and respiration detection on skin. Long-term wearability and functioning up to several days and under repeated stretching tests is demonstrated.
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Affiliation(s)
- Alexander Dallinger
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Kirill Keller
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Harald Fitzek
- Graz
Centre for Electron Microscopy (ZFE), Steyrergasse 17, 8010 Graz, Austria
- Institute
for Electron Microscopy and Nanoanalysis (FELMI), NAWI Graz, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Francesco Greco
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
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Monitoring respiratory rates with a wearable system using a stretchable strain sensor during moderate exercise. Med Biol Eng Comput 2019; 57:2741-2756. [DOI: 10.1007/s11517-019-02062-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 11/02/2019] [Indexed: 11/26/2022]
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Multipoint-Detection Strain Sensor with a Single Electrode Using Optical Ultrasound Generated by Carbon Nanotubes. SENSORS 2019; 19:s19183877. [PMID: 31505727 PMCID: PMC6767607 DOI: 10.3390/s19183877] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/22/2019] [Accepted: 09/07/2019] [Indexed: 12/13/2022]
Abstract
With the development of wearable devices, strain sensors have attracted large interest for the detection of human motion, movement, and breathing. Various strain sensors consisting of stretchable conductive materials have been investigated based on resistance and capacitance differences according to the strain. However, this method requires multiple electrodes for multipoint detection. We propose a strain sensor capable of multipoint detection with a single electrode, based on the ultrasound pulse-echo method. It consists of several transmitters of carbon nanotubes (CNTs) and a single polyvinylidene fluoride receiver. The strain sensor was fabricated using CNTs embedded in stretchable polydimethylsiloxane. The received data are characterized by the different times of transmission from the CNTs of each point depending on the strain, i.e., the sensor can detect the positions of the CNTs. This study demonstrates the application of the multipoint strain sensor with a single electrode for measurements up to a strain of 30% (interval of 1%). We considered the optical and acoustic energy losses in the sensor design. In addition, to evaluate the utility of the sensor, finger bending with three-point CNTs and flexible phantom bending with six-point CNTs for the identification of an S-curve having mixed expansion and compression components were carried out.
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Kim J, Chou E, Le J, Wong S, Chu M, Khine M. Soft Wearable Pressure Sensors for Beat-to-Beat Blood Pressure Monitoring. Adv Healthc Mater 2019; 8:e1900109. [PMID: 31033256 DOI: 10.1002/adhm.201900109] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/01/2019] [Indexed: 01/01/2023]
Abstract
Wrinkled gold thin films on elastomeric substrates are used as robust parallel plate electrodes for soft capacitive pressure sensors. The wrinkled structures create a robust integration with the polymer, allowing repeated normal force to deform the thin film without failure. By incorporating microridged structures that support the counter electrodes to create air cavities within the elastomeric dielectric layer, pressure sensitivity is further increased to 0.148 kPa-1 over a wide dynamic range of up to 10 kPa. The wide dynamic range and pressure sensitivity of the pressure sensor allow for consistent measurements of the pressure exerted by the radial artery located on the wrist. The soft capacitive pressure sensor displays comparable results when tested against an FDA approved device (Clearsight, Edwards Lifesciences, Irvine, CA) measuring beat-to-beat blood pressure. These soft pressure sensors using wrinkled thin films, therefore, illustrate considerable potential to continuously monitor beat-to-beat blood pressure.
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Affiliation(s)
- Joshua Kim
- Department of Materials Science and EngineeringUniversity of California Irvine Irvine CA 92697 USA
| | - En‐Fan Chou
- Department of Biomedical EngineeringUniversity of California Irvine Irvine CA 92697 USA
| | - Jamie Le
- Department of Biomedical EngineeringUniversity of California Irvine Irvine CA 92697 USA
| | - Sabrina Wong
- Department of Biomedical EngineeringUniversity of California Irvine Irvine CA 92697 USA
| | - Michael Chu
- Department of Biomedical EngineeringUniversity of California Irvine Irvine CA 92697 USA
| | - Michelle Khine
- Department of Materials Science and EngineeringUniversity of California Irvine Irvine CA 92697 USA
- Department of Biomedical EngineeringUniversity of California Irvine Irvine CA 92697 USA
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40
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Zhang Y, Guo H, Kim SB, Wu Y, Ostojich D, Park SH, Wang X, Weng Z, Li R, Bandodkar AJ, Sekine Y, Choi J, Xu S, Quaggin S, Ghaffari R, Rogers JA. Passive sweat collection and colorimetric analysis of biomarkers relevant to kidney disorders using a soft microfluidic system. LAB ON A CHIP 2019; 19:1545-1555. [PMID: 30912557 PMCID: PMC6830512 DOI: 10.1039/c9lc00103d] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The rich range of biomarkers in sweat and the ability to collect sweat in a non-invasive manner create interest in the use of this biofluid for assessments of health and physiological status, with potential applications that range from sports and fitness to clinical medicine. This paper introduces two important advances in recently reported classes of soft, skin-interfaced microfluidic systems for sweat capture and analysis: (1) a simple, broadly applicable means for collection of sweat that bypasses requirements for physical/mental exertion or pharmacological stimulation and (2) a set of enzymatic chemistries and colorimetric readout approaches for determining the concentrations of creatinine and urea in sweat, throughout ranges that are physiologically relevant. The results allow for routine, non-pharmacological capture of sweat for patient populations, such as infants and the elderly, that cannot be expected to sweat through exercise, and they create potential opportunities in the use of sweat for kidney disease screening/monitoring. Studies on human subjects demonstrate these essential capabilities, with quantitative comparisons to standard methods. The results expand the range of options available in microfluidic sampling and sensing of sweat for disease diagnostics and health monitoring.
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Affiliation(s)
- Yi Zhang
- Department of Biomedical, Biological, and Chemical Engineering, University of Missouri, Columbia, MO 65211, USA
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Chu M, Nguyen T, Pandey V, Zhou Y, Pham HN, Bar-Yoseph R, Radom-Aizik S, Jain R, Cooper DM, Khine M. Respiration rate and volume measurements using wearable strain sensors. NPJ Digit Med 2019; 2:8. [PMID: 31304358 PMCID: PMC6550208 DOI: 10.1038/s41746-019-0083-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/15/2019] [Indexed: 12/31/2022] Open
Abstract
Current methods for continuous respiration monitoring such as respiratory inductive or optoelectronic plethysmography are limited to clinical or research settings; most wearable systems reported only measures respiration rate. Here we introduce a wearable sensor capable of simultaneously measuring both respiration rate and volume with high fidelity. Our disposable respiration sensor with a Band-Aid© like formfactor can measure both respiration rate and volume by simply measuring the local strain of the ribcage and abdomen during breathing. We demonstrate that both metrics are highly correlated to measurements from a medical grade continuous spirometer on participants at rest. Additionally, we also show that the system is capable of detecting respiration under various ambulatory conditions. Because these low-powered piezo-resistive sensors can be integrated with wireless Bluetooth units, they can be useful in monitoring patients with chronic respiratory diseases in everyday settings.
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Affiliation(s)
- Michael Chu
- Department of Biomedical Engineering, University of California, Irvine, CA USA
| | - Thao Nguyen
- Department of Chemical Engineering, University of California, Irvine, CA USA
| | - Vaibhav Pandey
- Bren School of Information and Computer Sciences, University of California, Irvine, CA USA
| | - Yongxiao Zhou
- Department of Biomedical Engineering, University of California, Irvine, CA USA
| | - Hoang N. Pham
- Pediatric Exercise and Genomics Research Center, School of Medicine, University of California, Irvine, CA USA
| | - Ronen Bar-Yoseph
- Pediatric Exercise and Genomics Research Center, School of Medicine, University of California, Irvine, CA USA
- Department of Pediatrics, Rambam Medical Center, Haifa, Israel
| | - Shlomit Radom-Aizik
- Pediatric Exercise and Genomics Research Center, School of Medicine, University of California, Irvine, CA USA
| | - Ramesh Jain
- Bren School of Information and Computer Sciences, University of California, Irvine, CA USA
| | - Dan M. Cooper
- Pediatric Exercise and Genomics Research Center, School of Medicine, University of California, Irvine, CA USA
| | - Michelle Khine
- Department of Biomedical Engineering, University of California, Irvine, CA USA
- Department of Chemical Engineering, University of California, Irvine, CA USA
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42
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Xuan X, Kim JY, Hui X, Das PS, Yoon HS, Park JY. A highly stretchable and conductive 3D porous graphene metal nanocomposite based electrochemical-physiological hybrid biosensor. Biosens Bioelectron 2018; 120:160-167. [DOI: 10.1016/j.bios.2018.07.071] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/16/2018] [Accepted: 07/30/2018] [Indexed: 12/21/2022]
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43
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Wang J, Tenjimbayashi M, Tokura Y, Park JY, Kawase K, Li J, Shiratori S. Bionic Fish-Scale Surface Structures Fabricated via Air/Water Interface for Flexible and Ultrasensitive Pressure Sensors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:30689-30697. [PMID: 30003780 DOI: 10.1021/acsami.8b08933] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In recent years, wearable and flexible sensors have attracted considerable research interest and effort owing to their broad application prospects in wearable devices, robotics, health monitoring, and so on. High-sensitivity and low-cost pressure sensors are the primary requirement in practical application. Herein, a convenient and low-cost process to fabricate a bionic fish-scale structure poly(dimethylsiloxane) (PDMS) film via air/water interfacial formation technique is presented. High-sensitivity flexible pressure sensors can be constructed by assembling conductive films of graphene nanosheets into a microstructured film. Thanks to the unique fish-scale structures of PDMS films, the prepared pressure sensor shows excellent performance with high sensitivity (-70.86% kPa-1). In addition, our pressure sensors can detect weak signals, such as wrist pulses, respiration, and voice vibrations. Moreover, the whole process of pressure sensor preparation is cost-effective, eco-friendly, and controllable. The results indicate that the prepared pressure sensor has a profitable and efficient advantage in future applications for monitoring human physiological signals and sensing subtle touch, which may broaden its potential applications in wearable devices.
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Affiliation(s)
- Jian Wang
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Mizuki Tenjimbayashi
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Yuki Tokura
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Jun-Yong Park
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Koki Kawase
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Jiatu Li
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
| | - Seimei Shiratori
- Center for Material Design Science, School of Integrated Design Engineering , Keio University , 3-14-1 Hiyoshi , Yokohama 223-8522 , Japan
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Heikenfeld J, Jajack A, Rogers J, Gutruf P, Tian L, Pan T, Li R, Khine M, Kim J, Wang J, Kim J. Wearable sensors: modalities, challenges, and prospects. LAB ON A CHIP 2018; 18:217-248. [PMID: 29182185 PMCID: PMC5771841 DOI: 10.1039/c7lc00914c] [Citation(s) in RCA: 427] [Impact Index Per Article: 71.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Wearable sensors have recently seen a large increase in both research and commercialization. However, success in wearable sensors has been a mix of both progress and setbacks. Most of commercial progress has been in smart adaptation of existing mechanical, electrical and optical methods of measuring the body. This adaptation has involved innovations in how to miniaturize sensing technologies, how to make them conformal and flexible, and in the development of companion software that increases the value of the measured data. However, chemical sensing modalities have experienced greater challenges in commercial adoption, especially for non-invasive chemical sensors. There have also been significant challenges in making significant fundamental improvements to existing mechanical, electrical, and optical sensing modalities, especially in improving their specificity of detection. Many of these challenges can be understood by appreciating the body's surface (skin) as more of an information barrier than as an information source. With a deeper understanding of the fundamental challenges faced for wearable sensors and of the state-of-the-art for wearable sensor technology, the roadmap becomes clearer for creating the next generation of innovations and breakthroughs.
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Affiliation(s)
- J Heikenfeld
- Department of Electrical Engineering & Computer Science, Novel Devices Laboratory, University of Cincinnati, Cincinnati, OH 45221, USA
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Roh E, Lee HB, Kim DI, Lee NE. A Solution-Processable, Omnidirectionally Stretchable, and High-Pressure-Sensitive Piezoresistive Device. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1703004. [PMID: 28960525 DOI: 10.1002/adma.201703004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/25/2017] [Indexed: 05/21/2023]
Abstract
The development of omnidirectionally stretchable pressure sensors with high performance without stretching-induced interference has been hampered by many challenges. Herein, an omnidirectionally stretchable piezoresistive pressure-sensing device is demonstrated by combining an omniaxially stretchable substrate with a 3D micropattern array and solution-printing of electrode and piezoresistive materials. A unique substrate structural design and materials mean that devices that are highly sensitive are rendered, with a stable out-of-plane pressure response to both static (sensitivity of 0.5 kPa-1 and limit of detection of 28 Pa) and dynamic pressures and the minimized in-plane stretching responsiveness (a small strain gauge factor of 0.17), achieved through efficient strain absorption of the electrode and sensing materials. The device can detect human-body tremors, as well as measure the relative elastic properties of human skin. The omnidirectionally stretchable pressure sensor with a high pressure sensitivity and minimal stretch-responsiveness yields great potential to skin-attachable wearable electronics, human-machine interfaces, and soft robotics applications.
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Affiliation(s)
- Eun Roh
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, South Korea
| | - Han-Byeol Lee
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, South Korea
| | - Do-Il Kim
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, South Korea
| | - Nae-Eung Lee
- School of Advanced Materials Science & Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Kyunggi-do, 16419, South Korea
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Park HJ, Kim WJ, Ah CS, Jun Y, Yun YJ. Solution-processed Au–Ag core–shell nanoparticle-decorated yarns for human motion monitoring. RSC Adv 2017. [DOI: 10.1039/c6ra26860a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Wearable strain sensors based on Au–Ag core–shell nanoparticle decorated yarns were fabricated by a solution-based approach.
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Affiliation(s)
- Hyung Ju Park
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon 34129
- Republic of Korea
| | - Wan-Joong Kim
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon 34129
- Republic of Korea
| | - Chil Seong Ah
- Electronics and Telecommunications Research Institute (ETRI)
- Daejeon 34129
- Republic of Korea
| | - Yongseok Jun
- Department of Energy Engineering
- Konkuk University
- Seoul 05029
- Republic of Korea
| | - Yong Ju Yun
- Department of Energy Engineering
- Konkuk University
- Seoul 05029
- Republic of Korea
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