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Lee Y, So JH, Koo HJ. A Transparent Hydrogel-Ionic Conductor with High Water Retention and Self-Healing Ability. MATERIALS (BASEL, SWITZERLAND) 2024; 17:288. [PMID: 38255457 PMCID: PMC10817594 DOI: 10.3390/ma17020288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/04/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
This study presents a transparent and ion-conductive hydrogel with suppressed water loss. The hydrogel comprises agarose polymer doped with sucrose and sodium chloride salt (NaCl-Suc/A hydrogel). Sucrose increases the water retention of the agarose gel, and the Na and Cl ions dissolved in the gel provide ionic conductivity. The NaCl-Suc/A gel shows high retention capability and maintains a 45% water uptake after 4 h of drying at 60 °C without encapsulation at the optimum gel composition. The doped NaCl-Suc/A hydrogel demonstrates improved mechanical properties and ionic conductivity of 1.6 × 10-2 (S/cm) compared to the pristine agarose hydrogel. The self-healing property of the gel restores the electrical continuity when reassembled after cutting. Finally, to demonstrate a potential application of the ion-conductive hydrogel, a transparent and flexible pressure sensor is fabricated using the NaCl-Suc/A hydrogel, and its performance is demonstrated. The results of this study could contribute to solving problems with hydrogel-based devices such as rapid dehydration and poor mechanical properties.
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Affiliation(s)
- Yangwoo Lee
- Department of Chemical & Biomolecular Engineering, Seoul National University of Science & Technology, 232 Gongneung-ro, Nowon-gu, Seoul 01811, Republic of Korea;
| | - Ju-Hee So
- Material & Component Convergence R&D Department, Korea Institute of Industrial Technology, Ansan 15588, Republic of Korea
| | - Hyung-Jun Koo
- Department of Chemical & Biomolecular Engineering, Seoul National University of Science & Technology, 232 Gongneung-ro, Nowon-gu, Seoul 01811, Republic of Korea;
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Choi SG, Kang SH, Lee JY, Park JH, Kang SK. Recent advances in wearable iontronic sensors for healthcare applications. Front Bioeng Biotechnol 2023; 11:1335188. [PMID: 38162187 PMCID: PMC10757853 DOI: 10.3389/fbioe.2023.1335188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/04/2023] [Indexed: 01/03/2024] Open
Abstract
Iontronic sensors have garnered significant attention as wearable sensors due to their exceptional mechanical performance and the ability to maintain electrical performance under various mechanical stimuli. Iontronic sensors can respond to stimuli like mechanical stimuli, humidity, and temperature, which has led to exploration of their potential as versatile sensors. Here, a comprehensive review of the recent researches and developments on several types of iontronic sensors (e.g., pressure, strain, humidity, temperature, and multi-modal sensors), in terms of their sensing principles, constituent materials, and their healthcare-related applications is provided. The strategies for improving the sensing performance and environmental stability of iontronic sensors through various innovative ionic materials and structural designs are reviewed. This review also provides the healthcare applications of iontronic sensors that have gained increased feasibility and broader applicability due to the improved sensing performance. Lastly, outlook section discusses the current challenges and the future direction in terms of the applicability of the iontronic sensors to the healthcare.
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Affiliation(s)
- Sung-Geun Choi
- Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea
| | - Se-Hun Kang
- Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea
| | - Ju-Yong Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea
| | - Joo-Hyeon Park
- Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea
| | - Seung-Kyun Kang
- Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, Republic of Korea
- Nano Systems Institute SOFT Foundry, Seoul National University, Seoul, Republic of Korea
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Song Y, Ren W, Zhang Y, Liu Q, Peng Z, Wu X, Wang Z. Synergetic Monitoring of both Physiological Pressure and Epidermal Biopotential Based on a Simplified on-Skin-Printed Sensor Modality. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303301. [PMID: 37423977 DOI: 10.1002/smll.202303301] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/07/2023] [Indexed: 07/11/2023]
Abstract
Flexible electronic sensors show great potential for health monitoring but are usually limited to single sensing functionality. To enrich their functions, complicated device configurations, sophisticated material systems, and preparation processes are typically involved, obstructing their large-scale deployment and widespread application. Herein, to achieve a good balance between simplicity and multifunctionality, a new paradigm of sensor modality for both mechanical sensing and bioelectrical sensing is presented based on a single material system and a simple solution processing approach. The whole multifunctional sensors are constructed with a pair of highly conductive ultrathin electrodes (WPU/MXene-1) and an elastic micro-structured mechanical sensing layer (WPU/MXene-2), with the human skin serving as the substrate for the whole sensors. The resultant sensors show high pressure sensitivity and low skin-electrode interfacial impedance, enabling to synergetically monitor both physiological pressure (e.g., arterial pulse signals) and epidermal bioelectrical signals (including electrocardiograph and electromyography). The universality and extensibility of this methodology to construct multifunctional sensors with different material systems are also verified. This simplified sensor modality with enhanced multifunctionality provides a novel design concept to construct future smart wearables for health monitoring and medical diagnosis.
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Affiliation(s)
- Yangyang Song
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
- Med + X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wenjuan Ren
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
| | - Yiqun Zhang
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
- Med + X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Qi Liu
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
- Med + X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zhen Peng
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
- Med + X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaodong Wu
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
| | - Zhuqing Wang
- School of Mechanical Engineering, Sichuan University, Chengdu, 610065, China
- Med + X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
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Geng B, Zeng H, Luo H, Wu X. Construction of Wearable Touch Sensors by Mimicking the Properties of Materials and Structures in Nature. Biomimetics (Basel) 2023; 8:372. [PMID: 37622977 PMCID: PMC10452172 DOI: 10.3390/biomimetics8040372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/26/2023] Open
Abstract
Wearable touch sensors, which can convert force or pressure signals into quantitative electronic signals, have emerged as essential smart sensing devices and play an important role in various cutting-edge fields, including wearable health monitoring, soft robots, electronic skin, artificial prosthetics, AR/VR, and the Internet of Things. Flexible touch sensors have made significant advancements, while the construction of novel touch sensors by mimicking the unique properties of biological materials and biogenetic structures always remains a hot research topic and significant technological pathway. This review provides a comprehensive summary of the research status of wearable touch sensors constructed by imitating the material and structural characteristics in nature and summarizes the scientific challenges and development tendencies of this aspect. First, the research status for constructing flexible touch sensors based on biomimetic materials is summarized, including hydrogel materials, self-healing materials, and other bio-inspired or biomimetic materials with extraordinary properties. Then, the design and fabrication of flexible touch sensors based on bionic structures for performance enhancement are fully discussed. These bionic structures include special structures in plants, special structures in insects/animals, and special structures in the human body. Moreover, a summary of the current issues and future prospects for developing wearable sensors based on bio-inspired materials and structures is discussed.
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Affiliation(s)
| | | | - Hua Luo
- School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
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Zhang Y, Liu Q, Ren W, Song Y, Luo H, Han Y, He L, Wu X, Wang Z. Bioinspired Tactile Sensation Based on Synergistic Microcrack-Bristle Structure Design toward High Mechanical Sensitivity and Direction-Resolving Capability. RESEARCH (WASHINGTON, D.C.) 2023; 6:0172. [PMID: 37333971 PMCID: PMC10275619 DOI: 10.34133/research.0172] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/26/2023] [Indexed: 06/20/2023]
Abstract
Natural tactile sensation is complex, which involves not only contact force intensity detection but also the perception of the force direction, the surface texture, and other mechanical parameters. Nevertheless, the vast majority of the developed tactile sensors can only detect the normal force, but usually cannot resolve shear force or even distinguish the directions of the force. Here, we present a new paradigm of bioinspired tactile sensors for resolving both the intensity and the directions of mechanical stimulations via synergistic microcrack-bristle structure design and cross-shaped configuration engineering. The microcrack sensing structure gives high mechanical sensitivity to the tactile sensors, and the synergistic bristle structure further amplifies the sensitivity of the sensors. The cross-shaped configuration engineering of the synergistic microcrack-bristle structure further endows the tactile sensors with good capability to detect and distinguish the directions of the applied mechanical forces. The as-fabricated tactile sensors exhibit a high sensitivity (25.76 N-1), low detection limit (5.4 mN), desirable stability (over 2,500 cycles), and good capability to resolve both mechanical intensity and directional features. As promising application scenarios, surface texture recognition and biomimetic path explorations are successfully demonstrated with these tactile sensors. This newly proposed tactile sensation strategy and technology have great potential applications in ingenious tactile sensation and construction of various robotic and bionic prostheses with high operational dexterity.
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Affiliation(s)
- Yiqun Zhang
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
- Med+X Center for Manufacturing, West China Hospital,
Sichuan University, Chengdu 610041, China
| | - Qi Liu
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
- Med+X Center for Manufacturing, West China Hospital,
Sichuan University, Chengdu 610041, China
| | - Wenjuan Ren
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
| | - Yangyang Song
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
- Med+X Center for Manufacturing, West China Hospital,
Sichuan University, Chengdu 610041, China
| | - Hua Luo
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
| | - Yangyang Han
- State Key Laboratory of Polymer Materials Engineering,
Polymer Research Institute of Sichuan University, Chengdu 610065, China
| | - Liang He
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
| | - Xiaodong Wu
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
| | - Zhuqing Wang
- School of Mechanical Engineering,
Sichuan University, Chengdu 610065, China
- Med+X Center for Manufacturing, West China Hospital,
Sichuan University, Chengdu 610041, China
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