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Wei Y, Bhuyan P, Kwon SJ, Kim S, Bae Y, Singh M, Thanh Tran D, Ha M, Jeong KU, Ma X, Park B, Park S. Liquid Metal Grid Patterned Thin Film Devices Toward Absorption-Dominant and Strain-Tunable Electromagnetic Interference Shielding. NANO-MICRO LETTERS 2024; 16:248. [PMID: 39017957 PMCID: PMC11255180 DOI: 10.1007/s40820-024-01457-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 06/10/2024] [Indexed: 07/18/2024]
Abstract
The demand of high-performance thin-film-shaped deformable electromagnetic interference (EMI) shielding devices is increasing for the next generation of wearable and miniaturized soft electronics. Although highly reflective conductive materials can effectively shield EMI, they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously. Herein, soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented. The devices consist of liquid metal (LM) layer and LM grid-patterned layer separated by a thin elastomeric film, fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer. The devices demonstrate high electromagnetic shielding effectiveness (SE) (SET of up to 75 dB) with low reflectance (SER of 1.5 dB at the resonant frequency) owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures. Remarkably, the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain (resonant frequency shift from 81.3 to 71.3 GHz @ 33% strain) and is also capable of retaining shielding effectiveness even after multiple strain cycles. This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.
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Affiliation(s)
- Yuwen Wei
- Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Priyanuj Bhuyan
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Suk Jin Kwon
- Composites Research Division, Korea Institute of Materials Science, Changwon, 51508, Republic of Korea
| | - Sihyun Kim
- Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Yejin Bae
- Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Mukesh Singh
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Duy Thanh Tran
- Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Minjeong Ha
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Kwang-Un Jeong
- Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Xing Ma
- School of Materials Science and Engineering, and Sauvage Laboratory for Smart Materials, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong, 518055, People's Republic of China
| | - Byeongjin Park
- Composites Research Division, Korea Institute of Materials Science, Changwon, 51508, Republic of Korea.
| | - Sungjune Park
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
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Vasconez Martinez MG, Frauenlob M, Rothbauer M. An update on microfluidic multi-organ-on-a-chip systems for reproducing drug pharmacokinetics: the current state-of-the-art. Expert Opin Drug Metab Toxicol 2024; 20:459-471. [PMID: 38832686 DOI: 10.1080/17425255.2024.2362183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 05/28/2024] [Indexed: 06/05/2024]
Abstract
INTRODUCTION Advances in the accessibility of manufacturing technologies and iPSC-based modeling have accelerated the overall progress of organs-on-a-chip. Notably, the progress in multi-organ systems is not progressing with equal speed, indicating that there are still major technological barriers to overcome that may include biological relevance, technological usability as well as overall accessibility. AREAS COVERED We here review the progress in the field of multi-tissue- and body-on-a-chip pre and post- SARS-CoV-2 pandemic and review five selected studies with increasingly complex multi-organ chips aiming at pharmacological studies. EXPERT OPINION We discuss future and necessary advances in the field of multi-organ chips including how to overcome challenges regarding cell diversity, improved culture conditions, model translatability as well as sensor integrations to enable microsystems to cover organ-organ interactions in not only toxicokinetic but more importantly pharmacodynamic and -kinetic studies.
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Affiliation(s)
| | - Martin Frauenlob
- CellChipGroup, Institute of Applied Synthetic Chemistry, Technische Universitaet Wien, Vienna, Austria
| | - Mario Rothbauer
- Karl Chiari Lab for Orthopaedic Biology, Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria
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Zhu J, Li J, Tong Y, Hu T, Chen Z, Xiao Y, Zhang S, Yang H, Gao M, Pan T, Cheng H, Lin Y. Recent progress in multifunctional, reconfigurable, integrated liquid metal-based stretchable sensors and standalone systems. PROGRESS IN MATERIALS SCIENCE 2024; 142:101228. [PMID: 38745676 PMCID: PMC11090487 DOI: 10.1016/j.pmatsci.2023.101228] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Possessing a unique combination of properties that are traditionally contradictory in other natural or synthetical materials, Ga-based liquid metals (LMs) exhibit low mechanical stiffness and flowability like a liquid, with good electrical and thermal conductivity like metal, as well as good biocompatibility and room-temperature phase transformation. These remarkable properties have paved the way for the development of novel reconfigurable or stretchable electronics and devices. Despite these outstanding properties, the easy oxidation, high surface tension, and low rheological viscosity of LMs have presented formidable challenges in high-resolution patterning. To address this challenge, various surface modifications or additives have been employed to tailor the oxidation state, viscosity, and patterning capability of LMs. One effective approach for LM patterning is breaking down LMs into microparticles known as liquid metal particles (LMPs). This facilitates LM patterning using conventional techniques such as stencil, screening, or inkjet printing. Judiciously formulated photo-curable LMP inks or the introduction of an adhesive seed layer combined with a modified lift-off process further provide the micrometer-level LM patterns. Incorporating porous and adhesive substrates in LM-based electronics allows direct interfacing with the skin for robust and long-term monitoring of physiological signals. Combined with self-healing polymers in the form of substrates or composites, LM-based electronics can provide mechanical-robust devices to heal after damage for working in harsh environments. This review provides the latest advances in LM-based composites, fabrication methods, and their novel and unique applications in stretchable or reconfigurable sensors and resulting integrated systems. It is believed that the advancements in LM-based material preparation and high-resolution techniques have opened up opportunities for customized designs of LM-based stretchable sensors, as well as multifunctional, reconfigurable, highly integrated, and even standalone systems.
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Affiliation(s)
- Jia Zhu
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Jiaying Li
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yao Tong
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Taiqi Hu
- School of Electrical Engineering and Automation, Jiangxi University of Science and Technology, Ganzhou 341000, P. R. China
| | - Ziqi Chen
- School of Physical Sciences, University of Science and Technology of China, Hefei 230026, PR China
| | - Yang Xiao
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Senhao Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Hongbo Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215011, PR China
| | - Min Gao
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Taisong Pan
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Huanyu Cheng
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuan Lin
- School of Material and Energy, University of Electronic Science and Technology of China, Chengdu 610054, China
- Medico-Engineering Cooperation on Applied Medicine Research Center, University of Electronics Science and Technology of China, Chengdu 610054, China
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Lu G, Ni E, Jiang Y, Wu W, Li H. Room-Temperature Liquid Metals for Flexible Electronic Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304147. [PMID: 37875665 DOI: 10.1002/smll.202304147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/26/2023] [Indexed: 10/26/2023]
Abstract
Room-temperature gallium-based liquid metals (RT-GaLMs) have garnered significant interest recently owing to their extraordinary combination of fluidity, conductivity, stretchability, self-healing performance, and biocompatibility. They are ideal materials for the manufacture of flexible electronics. By changing the composition and oxidation of RT-GaLMs, physicochemical characteristics of the liquid metal can be adjusted, especially the regulation of rheological, wetting, and adhesion properties. This review highlights the advancements in the liquid metals used in flexible electronics. Meanwhile related characteristics of RT-GaLMs and underlying principles governing their processing and applications for flexible electronics are elucidated. Finally, the diverse applications of RT-GaLMs in self-healing circuits, flexible sensors, energy harvesting devices, and epidermal electronics, are explored. Additionally, the challenges hindering the progress of RT-GaLMs are discussed, while proposing future research directions and potential applications in this emerging field. By presenting a concise and critical analysis, this paper contributes to the advancement of RT-GaLMs as an advanced material applicable for the new generation of flexible electronics.
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Affiliation(s)
- Guixuan Lu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Erli Ni
- The Institute for Advanced Studies of Wuhan University, Wuhan University, Wuhan, Hubei, 430072, China
| | - Yanyan Jiang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Weikang Wu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
| | - Hui Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, China
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Xing S, Liu Y. Functional micro-/nanostructured gallium-based liquid metal for biochemical sensing and imaging applications. Biosens Bioelectron 2024; 243:115795. [PMID: 37913588 DOI: 10.1016/j.bios.2023.115795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
In recent years, liquid metals (LMs) have garnered increasing attention for their expanded applicability, and wide application potential in various research fields. Among them, gallium (Ga)-based LMs exhibit remarkable analytical performance in electrical and optical sensors, thanks to their excellent conductivity, large surface area, biocompatibility, small bandgap, and high elasticity. This review comprehensively summarizes the latest advancements in functional micro-/nanostructured Ga-based LMs for biochemical sensing and imaging applications. Firstly, the electrical, optical, and biocompatible features of Ga-based LM micro-/nanoparticles are briefly discussed, along with the manufacturing and functionalization processes. Subsequently, we demonstrate the utilization of Ga-based LMs in biochemical sensing techniques, encompassing electrochemistry, electrochemiluminescence, optical sensing techniques, and various biomedical imaging. Lastly, we present an insightful perspective on promising research directions and remaining challenges in LM-based biochemical sensing and imaging applications.
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Affiliation(s)
- Simin Xing
- Department of Chemistry, Beijing Key Laboratory for Analytical Methods and Instrumentation, Kay Lab of Bioorganic Phosphorus Chemistry and Chemical Biology of Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Yang Liu
- Department of Chemistry, Beijing Key Laboratory for Analytical Methods and Instrumentation, Kay Lab of Bioorganic Phosphorus Chemistry and Chemical Biology of Ministry of Education, Tsinghua University, Beijing, 100084, China.
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6
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Stokes K, Clark K, Odetade D, Hardy M, Goldberg Oppenheimer P. Advances in lithographic techniques for precision nanostructure fabrication in biomedical applications. DISCOVER NANO 2023; 18:153. [PMID: 38082047 PMCID: PMC10713959 DOI: 10.1186/s11671-023-03938-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/04/2023] [Indexed: 01/31/2024]
Abstract
Nano-fabrication techniques have demonstrated their vital importance in technological innovation. However, low-throughput, high-cost and intrinsic resolution limits pose significant restrictions, it is, therefore, paramount to continue improving existing methods as well as developing new techniques to overcome these challenges. This is particularly applicable within the area of biomedical research, which focuses on sensing, increasingly at the point-of-care, as a way to improve patient outcomes. Within this context, this review focuses on the latest advances in the main emerging patterning methods including the two-photon, stereo, electrohydrodynamic, near-field electrospinning-assisted, magneto, magnetorheological drawing, nanoimprint, capillary force, nanosphere, edge, nano transfer printing and block copolymer lithographic technologies for micro- and nanofabrication. Emerging methods enabling structural and chemical nano fabrication are categorised along with prospective chemical and physical patterning techniques. Established lithographic techniques are briefly outlined and the novel lithographic technologies are compared to these, summarising the specific advantages and shortfalls alongside the current lateral resolution limits and the amenability to mass production, evaluated in terms of process scalability and cost. Particular attention is drawn to the potential breakthrough application areas, predominantly within biomedical studies, laying the platform for the tangible paths towards the adoption of alternative developing lithographic technologies or their combination with the established patterning techniques, which depends on the needs of the end-user including, for instance, tolerance of inherent limits, fidelity and reproducibility.
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Affiliation(s)
- Kate Stokes
- Advanced Nanomaterials Structures and Applications Laboratories, School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Kieran Clark
- Advanced Nanomaterials Structures and Applications Laboratories, School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - David Odetade
- Advanced Nanomaterials Structures and Applications Laboratories, School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Mike Hardy
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, BT9 5DL, UK
- Centre for Quantum Materials and Technology, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Pola Goldberg Oppenheimer
- Advanced Nanomaterials Structures and Applications Laboratories, School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Healthcare Technologies Institute, Institute of Translational Medicine, Mindelsohn Way, Birmingham, B15 2TH, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK.
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7
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Yuan Q, Fang H, Wu X, Wu J, Luo X, Peng R, Xu S, Yan S. Self-Adhesive, Biocompatible, Wearable Microfluidics with Erasable Liquid Metal Plasmonic Hotspots for Glucose Detection in Sweat. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37903285 DOI: 10.1021/acsami.3c11746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Sweat is a noninvasive metabolite that can provide clinically meaningful information about physical conditions without harming the body. Glucose, a vital component in sweat, is closely related to blood glucose levels, and changes in its concentration can reflect the health status of diabetics. We introduce a self-adhesive, wearable microfluidic chip with erasable liquid metal plasmonic hotspots for the precise detection of glucose concentration in sweat. The self-adhesive, wearable microfluidic chip is made from modified polydimethylsiloxane (PDMS) with enhanced stickiness, enabling conformal contact with the skin, and can collect, deliver, and store sweat. The plasmonic hotspots are located inside the microfluidic channel, are generated by synthesizing silver nanostructures on liquid metal, and can be removed in the alkaline solution. It indicates the erasable and reproducible nature of the plasmonic hotspots. The detection method is based on surface-enhanced Raman spectroscopy (SERS), which allows for accurate detection of the glucose concentration. To enhance the sensitive detection of glucose, the SERS substrate is modified by 4-mercaptophenylboronic acid to achieve the limit of detection of 1 ng/L glucose, which is much lower than the physiological conditions (7.2-25.2 μg/L). The developed microfluidic chip is soft, stretchable, and nontoxic, bringing new possibilities to wearable sweat-sensing devices.
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Affiliation(s)
- Qingwei Yuan
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Hui Fang
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Xiuru Wu
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Jialin Wu
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Xie Luo
- Department of Endocrinology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Ran Peng
- College of Marine Engineering, Dalian Maritime University, Dalian 116026, China
| | - Shanshan Xu
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Sheng Yan
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518060, China
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Liu Y, Zhang C, Chen Y, Yin R, He P, Zhao W. Rational Design of Conductive Pathways in Flexible Tactile Sensors via Indirect 3D-Printing of Liquid Metal for High-Precision Monitoring and Recognition. ACS APPLIED MATERIALS & INTERFACES 2023; 15:38572-38580. [PMID: 37526636 DOI: 10.1021/acsami.3c07237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Highly sensitive and conformal sensors are essential for the implementation of human-machine interfaces, health monitoring, and rehabilitation prostheses. The proper adjustment of conductive pathways in the sensing materials is essential for their sensitive transduction of mechanical stimuli into electrical signals. However, the rational, precise, and wide-range control of electrical networks within traditional conductive composites is difficult due to the randomly distributed fillers. Herein, we adopt an indirect 3D-printing method to fabricate pressure sensors with various microchannels for liquid metal (LM) to form consistent and tunable conductive pathways. LM is highly conductive, fluidic, and incompressible at ambient conditions, which guarantees the reliable regulation and function of our pressure sensor. Additive manufacturing provides a facile way to construct complicated microchannels with different lengths, different orientations, cross-sectional sizes, depth-width ratios, and shapes, which can effectively modulate the sensitivity and the sensing range. Under the optimized structural configurations, our sensor achieves a high sensitivity of 1.139 kPa-1, a detection range of 0-68 kPa (loading process), and stability of over 5000 cycles, whose sensing performance is better than most microchannel-filled LM sensors. It can achieve high-accuracy monitoring of pulse, speaking and gestures, and exhibit a full recognition of objects under the assistance of machine learning. This work can provide new ideas on the design of conductive pathways in flexible electronics and expand the application of recyclable LM in human-machine interfaces.
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Affiliation(s)
- Yaming Liu
- Sauvage Laboratory for Smart Materials, The School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- State Key Laboratory of Advanced Welding & Joining, Harbin Institute of Technology, Harbin 150001, People's Republic of China
| | - Chen Zhang
- Sauvage Laboratory for Smart Materials, The School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
| | - Youyou Chen
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- State Key Laboratory of Advanced Welding & Joining, Harbin Institute of Technology, Harbin 150001, People's Republic of China
- Laboratory for Smart Materials, The School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
| | - Rui Yin
- Sauvage Laboratory for Smart Materials, The School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
| | - Peng He
- State Key Laboratory of Advanced Welding & Joining, Harbin Institute of Technology, Harbin 150001, People's Republic of China
| | - Weiwei Zhao
- Sauvage Laboratory for Smart Materials, The School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, People's Republic of China
- State Key Laboratory of Advanced Welding & Joining, Harbin Institute of Technology, Harbin 150001, People's Republic of China
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Kashaninejad N, Nguyen NT. Microfluidic solutions for biofluids handling in on-skin wearable systems. LAB ON A CHIP 2023; 23:913-937. [PMID: 36628970 DOI: 10.1039/d2lc00993e] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
On-skin wearable systems for biofluid sampling and biomarker sensing can revolutionize the current practices in healthcare monitoring and personalized medicine. However, there is still a long path toward complete market adoption and acceptance of this fascinating technology. Accordingly, microfluidic science and technology can provide excellent solutions for bridging the gap between basic research and clinical research. The research gap has led to the emerging field of epidermal microfluidics. Moreover, recent advances in the fabrication of highly flexible and stretchable microfluidic systems have revived the concept of micro elastofluidics, which can provide viable solutions for on-skin wearable biofluid handling. In this context, this review highlights the current state-of-the-art platforms in this field and discusses the potential technologies that can be used for on-skin wearable devices. Toward this aim, we first compare various microfluidic platforms that could be used for on-skin wearable devices. These platforms include semiconductor-based, polymer-based, liquid metal-based, paper-based, and textile-based microfluidics. Next, we discuss how these platforms can enhance the stretchability of on-skin wearable biosensors at the device level. Next, potential microfluidic solutions for collecting, transporting, and controlling the biofluids are discussed. The application of finger-powered micropumps as a viable solution for precise and on-demand biofluid pumping is highlighted. Finally, we present the future directions of this field by emphasizing the applications of droplet-based microfluidics, stretchable continuous-flow micro elastofluidics, stretchable superhydrophobic surfaces, liquid beads as a form of digital micro elastofluidics, and topological liquid diodes that received less attention but have enormous potential to be integrated into on-skin wearable devices.
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Affiliation(s)
- Navid Kashaninejad
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia.
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia.
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Cao UMN, Zhang Y, Chen J, Sayson D, Pillai S, Tran SD. Microfluidic Organ-on-A-chip: A Guide to Biomaterial Choice and Fabrication. Int J Mol Sci 2023; 24:3232. [PMID: 36834645 PMCID: PMC9966054 DOI: 10.3390/ijms24043232] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/29/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Organ-on-A-chip (OoAC) devices are miniaturized, functional, in vitro constructs that aim to recapitulate the in vivo physiology of an organ using different cell types and extracellular matrix, while maintaining the chemical and mechanical properties of the surrounding microenvironments. From an end-point perspective, the success of a microfluidic OoAC relies mainly on the type of biomaterial and the fabrication strategy employed. Certain biomaterials, such as PDMS (polydimethylsiloxane), are preferred over others due to their ease of fabrication and proven success in modelling complex organ systems. However, the inherent nature of human microtissues to respond differently to surrounding stimulations has led to the combination of biomaterials ranging from simple PDMS chips to 3D-printed polymers coated with natural and synthetic materials, including hydrogels. In addition, recent advances in 3D printing and bioprinting techniques have led to the powerful combination of utilizing these materials to develop microfluidic OoAC devices. In this narrative review, we evaluate the different materials used to fabricate microfluidic OoAC devices while outlining their pros and cons in different organ systems. A note on combining the advances made in additive manufacturing (AM) techniques for the microfabrication of these complex systems is also discussed.
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Affiliation(s)
| | | | | | | | | | - Simon D. Tran
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, 3640 University Street, Montreal, QC H3A 0C7, Canada
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Yang B, Yang Z, Tang L. Recent progress in fiber-based soft electronics enabled by liquid metal. Front Bioeng Biotechnol 2023; 11:1178995. [PMID: 37187888 PMCID: PMC10175636 DOI: 10.3389/fbioe.2023.1178995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Soft electronics can seamlessly integrate with the human skin which will greatly improve the quality of life in the fields of healthcare monitoring, disease treatment, virtual reality, and human-machine interfaces. Currently, the stretchability of most soft electronics is achieved by incorporating stretchable conductors with elastic substrates. Among stretchable conductors, liquid metals stand out for their metal-grade conductivity, liquid-grade deformability, and relatively low cost. However, the elastic substrates usually composed of silicone rubber, polyurethane, and hydrogels have poor air permeability, and long-term exposure can cause skin redness and irritation. The substrates composed of fibers usually have excellent air permeability due to their high porosity, making them ideal substrates for soft electronics in long-term applications. Fibers can be woven directly into various shapes, or formed into various shapes on the mold by spinning techniques such as electrospinning. Here, we provide an overview of fiber-based soft electronics enabled by liquid metals. An introduction to the spinning technology is provided. Typical applications and patterning strategies of liquid metal are presented. We review the latest progress in the design and fabrication of representative liquid metal fibers and their application in soft electronics such as conductors, sensors, and energy harvesting. Finally, we discuss the challenges of fiber-based soft electronics and provide an outlook on future prospects.
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Affiliation(s)
- Bowen Yang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Zihan Yang
- Fashion Accessory Art and Engineering College, Beijing Institute of Fashion Technology, Beijing, China
- *Correspondence: Zihan Yang, ; Lixue Tang,
| | - Lixue Tang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Capital Medical University, Beijing, China
- *Correspondence: Zihan Yang, ; Lixue Tang,
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12
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Ma B, Zhang J, Chen G, Chen Y, Xu C, Lei L, Liu H. Shape-Programmable Liquid Metal Fibers. BIOSENSORS 2022; 13:bios13010028. [PMID: 36671863 PMCID: PMC9856024 DOI: 10.3390/bios13010028] [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] [Received: 11/28/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 05/28/2023]
Abstract
Conductive and stretchable fibers are the cornerstone of intelligent textiles and imperceptible electronics. Among existing fiber conductors, gallium-based liquid metals (LMs) featuring high conductivity, fluidity, and self-healing are excellent candidates for highly stretchable fibers with sensing, actuation, power generation, and interconnection functionalities. However, current LM fibers fabricated by direct injection or surface coating have a limitation in shape programmability. This hinders their applications in functional fibers with tunable electromechanical response and miniaturization. Here, we reported a simple and efficient method to create shape-programmable LM fibers using the phase transition of gallium. Gallium metal wires in the solid state can be easily shaped into a 3D helical structure, and the structure can be preserved after coating the wire with polyurethane and liquifying the metal. The 3D helical LM fiber offered enhanced stretchability with a high breaking strain of 1273% and showed invariable conductance over 283% strain. Moreover, we can reduce the fiber diameter by stretching the fiber during the solidification of polyurethane. We also demonstrated applications of the programmed fibers in self-powered strain sensing, heart rate monitoring, airflow, and humidity sensing. This work provided simple and facile ways toward functional LM fibers, which may facilitate the broad applications of LM fibers in e-skins, wearable computation, soft robots, and smart fabrics.
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13
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Zhang T, Ratajczak AM, Chen H, Terrell JA, Chen C. A Step Forward for Smart Clothes─Fabric-Based Microfluidic Sensors for Wearable Health Monitoring. ACS Sens 2022; 7:3857-3866. [PMID: 36455259 DOI: 10.1021/acssensors.2c01827] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
We report the first demonstration of fabric-based microfluidics for wearable sensing. A new technology to develop microfluidics on fabrics, as a part of an undergarment, is described here. Compared to conventional microfluidics from polydimethylsiloxane, fabric-based microfluidics are simple to make, robust, and suitable for efficient sweat delivery. Specifically, acrylonitrile butadiene styrene (ABS) films with precut microfluidic patterns were infused through fabrics to form hydrophobic areas in a specially controlled sandwich structure. Experimental tests and simulations confirmed the sweat delivery efficiency of the microfluidics. Electrodes were screen-printed onto the fabric-based microfluidic. A novel wearable potentiometer based on Arduino was also developed as the transducer and signal readouts, which was low-cost, standardized, open-source, and capable of wireless data transfer. We applied the sensor system as a standalone or as a module of a T-shirt to quantify [Ca2+] in a wearer's sweat, with physiological and accurate results generated. Overall, this work represents a critical step in turning regular undergarments into biochemically smart platforms for health monitoring, which will broadly benefit human healthcare.
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Affiliation(s)
- Tao Zhang
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, 21250, United States
| | - Adam Michael Ratajczak
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, 21250, United States
| | - Hui Chen
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, 21250, United States
| | - John A Terrell
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, 21250, United States
| | - Chengpeng Chen
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, 21250, United States
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14
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Yan S, Yuan Q, Wu J, Jia Z. A free-standing, phase-change liquid metal mold for 3D flexible microfluidics. Front Bioeng Biotechnol 2022; 10:1094294. [PMID: 36545676 PMCID: PMC9760860 DOI: 10.3389/fbioe.2022.1094294] [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: 11/09/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022] Open
Abstract
This paper describes a method to fabricate the 3D microfluidic channel using the free-standing, phase-change gallium mold. Three approaches to prepare the free-standing gallium molds are described. The solid metal framework is strong enough to stand against the gravity. After casting, the embedded gallium molds are melted from solid to liquid and then extracted from the encasing elastomer to form the 3D microfluidic channel due to the phase change property. Since this method is compatible with many encasing materials (e.g., elastomers, gels, resins, ceramics), the encasing materials will bring novel functionalities to the microfluidic chip. Two proof-of-concept experiments have been demonstrated. Firstly, a soft, sticky, on-skin microfluidic cooler is developed based on this method to deliver the focused, minimal invasive cooling power at arbitrary skins of human body with temperature control. Secondly, an ultra-stretchable viscoelastic microchannel with the ultra-soft base is fabricated to continuously tune the viscoelastic particle focusing with a large dynamic range. This proposed technique suggests the new possibilities for the development of lab-on-a-chip applications.
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Affiliation(s)
- Sheng Yan
- Institute for Advanced Study, Shenzhen University, Shenzhen, China,*Correspondence: Sheng Yan,
| | - Qingwei Yuan
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, China
| | - Jialin Wu
- Nanophotonics Research Center, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, China
| | - Zixuan Jia
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
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15
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Zhang J, Ma B, Chen G, Chen Y, Xu C, Hao Q, Zhao C, Liu H. Surface-Embedded Liquid Metal Electrodes with Abrasion Resistance via Direct Magnetic Printing. ACS APPLIED MATERIALS & INTERFACES 2022; 14:53405-53412. [PMID: 36382935 DOI: 10.1021/acsami.2c15282] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Gallium-based liquid metals (LMs) featuring both high conductivity and fluidity are ideal conductors for soft and stretchable electronics. However, their liquid nature is a double-edged sword in many key applications since LMs are inherently prone to mechanical damage. Although additional encapsulation is frequently used for the protection of delicate LM electrodes, it hinders the electrical interfacing with other objects for interconnection, sensing, and stimulation. Here, different from conventional patterning methods that deposit LM on or inside substrates, we for the first time report a simple strategy to create surface-embedded LM of eutectic gallium-indium (EGaIn) circuits with mechanical damage endurance. This was achieved by using direct magnetic printing to overcome the high surface tension of LM, allowing it to be passively filled into the laser-patterned microgrooves on soft substrates. We show that the surface-embedded LM circuits are resistant to mechanical erasure, washing, and peeling. We also show the applications of our surface-embedded LM electrodes in respiration monitoring and electrical stimulation of nerves. This work provides a simple and efficient way to create mechanically reliable LM microelectrodes, holding great promise for wearable and implantable bioelectronics.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Biao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Gangsheng Chen
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yi Chen
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chengtao Xu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Qing Hao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chao Zhao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Hong Liu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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16
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Tao Y, Han F, Shi C, Yang R, Chen Y, Ren Y. Liquid Metal-Based Flexible and Wearable Sensor for Functional Human-Machine Interface. MICROMACHINES 2022; 13:1429. [PMID: 36144052 PMCID: PMC9504365 DOI: 10.3390/mi13091429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 08/22/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Rigid sensors are a mature type of sensor, but their poor deformation and flexibility limit their application range. The appearance and development of flexible sensors provide an opportunity to solve this problem. In this paper, a resistive flexible sensor utilizes gallium-based liquid metal (eutectic gallium indium alloy, EGaIn) and poly(dimethylsiloxane) (PDMS) and is fabricated using an injecting thin-line patterning technique based on soft lithography. Combining the scalable fabrication process and unique wire-shaped liquid metal design enables sensitive multifunctional measurement under stretching and bending loads. Furthermore, the flexible sensor is combined with the glove to demonstrate the application of the wearable sensor glove in the detection of finger joint angle and gesture control, which offers the ability of integration and multifunctional sensing of all-soft wearable physical microsystems for human-machine interfaces. It shows its application potential in medical rehabilitation, intelligent control, and so on.
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