Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin

Kim, Jeonghyun; Salvatore, Giovanni A.; Araki, Hitoshi; Chiarelli, Antonio Maria; Xie, Zhaoqian; Banks, Anthony; Sheng, Xing; Wang, Kun; Lee, Jung Woo; Jang, Kyung In; Heo, Seung Yun; Cho, Kyoungyeon; Luo, Hangzai; Zimmerman, Benjamin; Kim, Joonhee; Yan, Lingqing; Feng, Xue; Xu, Sheng; Fabiani, Monica; Gratton, Gabriele; Huang, Yonggang; Paik, Ungyu; Li, Jinghua

doi:10.1126/sciadv.1600418

Cited by 355 publications

(333 citation statements)

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“…The adhesive has biocompatibilities and conformal interfaces with low modulus. 26 For single device measurement, an NFC reader (AMS Inc., Cupertino, CA, USA) was used for data capture at a distance of 5 mm. For multi-device monitoring, a custombuilt wireless setup was introduced.…”

Section: Wireless Measurements Of Various Strainmentioning

confidence: 99%

“…In the case of a strain sensor, when wireless transmission functions, including power and data transfer, are not incorporated, a hard wire connection is required with an external measuring device, which degrades the durability of the device and significantly limits the user's activity when worn. Recent work demonstrates various wireless chemical and biological sensor systems with Bluetooth 23,24 and near-field-communication (NFC) [25][26][27] capabilities, the latter of which can also be operated in a battery-free mode via power harvesting. However, previously reported liquid metal-based antennas tend to be unsuitable for skin-attachable applications in terms of size or thickness, mostly because of limitations in the injection method.…”

Section: Introductionmentioning

confidence: 99%

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A skin-attachable, stretchable integrated system based on liquid GaInSn for wireless human motion monitoring with multi-site sensing capabilities

et al. 2017

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This paper introduces a liquid-metal integrated system that combines soft electronics materials and engineering designs with advanced near-field-communication (NFC) functionality for human motion sensing. All of the active components, that is, strain sensor, antenna and interconnections, in this device are made of liquid metal, and the device has unique gel-like characteristics and stretchability. Patterning procedures based on selective wetting properties of the reduced GaInSn enable a skin-attachable, miniaturized layout, in which the diameter of the device is less than 2 cm. Electromechanical characterization of the strain sensor and antenna reveals their behaviors under large uniaxial tensile and compressive strains, as well as more complex modes of deformation. Demonstrations of these devices involve their use in monitoring various human motions in a purely wireless fashion; examples include wrist flexion, movements of the vocal cord and finger motion. This simple platform has potential for use in human-machine interfaces for prosthetic control and other applications. NPG Asia Materials (2017) 9, e443; doi:10.1038/am.2017.189; published online 27 October 2017 INTRODUCTION Skin-mounted, deformable devices capable of sensing various signals such as strain, pressure and temperature can be used in a variety of applications ranging from health monitoring systems and personal diagnostics to human-machine interfaces. 1 Advanced concepts in stretchable materials and mechanics principles form the basis for devices that can gently laminate onto the soft and curvilinear surfaces of human skin or conformally wrap onto internal organs of the body. 2-5 Gallium-based liquid metals are highly suitable candidates for such applications due to their unlimited deformability while maintaining excellent metallic conductivity. The use of gallium-based liquid-metal alloys confined in elastomeric enclosures provides intrinsically stretchable properties that maintain bulk electrical conductivity with high stretchability. 6 Additionally, unlike mercury, gallium is safe to use in ambient environment due to its low vapor pressure. 7,8 By taking full advantage of the deformability and nontoxicity of the liquid metal, many research groups have utilized liquid metal for wearable

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Section: Wireless Measurements Of Various Strainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A skin-attachable, stretchable integrated system based on liquid GaInSn for wireless human motion monitoring with multi-site sensing capabilities

et al. 2017

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“…Finally, advances in devices and algorithms for seizure prediction may enable continuous noninvasive EEG and physiological signal monitoring (57). These technologies could result in a paradigm shift to acute versus chronic treatment for the large proportion of epilepsy patients who have infrequent seizures but receive chronic AED treatment.…”

Section: Current and Future Trends In The Development Of Antiepileptimentioning

confidence: 99%

Epilepsy Treatment: A Futurist View

Privitera

2017

Epilepsy Curr

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Advances in epilepsy treatment are occurring at a rapid pace, and it is challenging for us to keep up with the latest in our field. As we struggle to keep up with the literature and concentrate on our own research and clinical work, we often fail to exercise our imagination and envision what our field will be like in future decades. This was the assignment to the speakers for the Presidential Symposium at the 2016 American Epilepsy Society Annual Meeting. I challenged the experts to step outside the frame of their usual daily work to imagine what epilepsy treatment would and should look like for the next generation of epilepsy specialists and their patients. As you will read in the following sections, the speakers truly stepped up to the challenge to look into the crystal ball. The following are summaries of each lecture that describe the current state, existing cutting edge ideas, and some surprising predictions for the future. I am grateful for the tremendous effort these experts put into this challenge and hope they stimulate your imagination so you will work to bring these advances to our patients.

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“…In fact, many studies have examined flexible and stretchable sensors to monitor health data [1][2][3][4][5][6][7][8] such as skin temperature, [9][10][11] electrocardiogram (ECG), [12][13][14][15][16][17] chemical contents in the body through sweat, [18][19][20][21][22][23] and activity. [24,25] These demonstrations are steps toward future wearable multifunctional flexible electronic devices by further developing into a system with improved reliability.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, many reports still employ both ultrathin film flexible devices and relatively thick films (several hundred micrometers). [1,[4][5][6][7]9,12,16,18,19,22,28] However, the effect of film thickness on sensing has yet to be discussed, although a systematical study is important to realize precise health data recordings. In addition to the wearability and film thickness depedences, biocompatibility of the sensor and film materials is another important parameter to consider for the practical application as a wearable device.…”

mentioning

confidence: 99%

Efficient Skin Temperature Sensor and Stable Gel‐Less Sticky ECG Sensor for a Wearable Flexible Healthcare Patch

Yamamoto

Takada

et al. 2017

Adv Healthcare Materials

242

190

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Because a wearable device comprised of a flexible film should be comfortable to wear over the skin, several reports have focused on the film thickness to prepare ultrathin films that are a few micrometers or nanometers thick. [26,27] Thinning a film to this scale should realize a film capable of covering the skin asperity conformally, resulting in a good comfort while wearing and a relatively strong adhesion on skin without glue. However, ultrathin films can be difficult to handle and attach to skin. Additionally, assembling other components such as a signal processing circuit and battery without sacrificing the advantage of thickness remains challenging. Thus, many reports still employ both ultrathin film flexible devices and relatively thick films (several hundred micrometers). [1,[4][5][6][7]9,12,16,18,19,22,28] However, the effect of film thickness on sensing has yet to be discussed, although a systematical study is important to realize precise health data recordings. In addition to the wearability and film thickness depedences, biocompatibility of the sensor and film materials is another important parameter to consider for the practical application as a wearable device.In this study, we explore the dependence of the temperature change, which is measured by a printed temperature sensor fabricated on polyethylene terephthalate (PET), on thickness. A thick film was selected due to handling ease and ability to integrate other components in the future. However, some sensors such as an ECG sensor must attach onto skin with good adhesion without sacrificing conductivity, and a relatively thick flexible film itself cannot attach to skin without an adhesion layer. To create good adhesion between an ECG sensor and skin without losing conductivity, a high adhesive conductive polymer onto skin is also developed. Although gel-based electrodes are often used in medical applications, gel-based electrodes are unsuited for long-time measurements due to skin irritation. [15] Thus, we developed a gel-less sticky electrode using biocompatible materials by characterizing the adhesion, impedance between skin and the ECG sensor, and repeatability for use. Finally, as a proofof-concept demonstration, simultaneous efficient skin temperature and ECG signal recordings were conducted using a conductive polymer with an optimized film thickness. Figure 1a describes an integrated device image with a temperature sensor, an ECG sensor, an equivalent circuit between Wearable, flexible healthcare devices, which can monitor health data to predict and diagnose disease in advance, benefit society. Toward this future, various flexible and stretchable sensors as well as other components are demonstrated by arranging materials, structures, and processes. Although there are many sensor demonstrations, the fundamental characteristics such as the dependence of a temperature sensor on film thickness and the impact of adhesive for an electrocardiogram (ECG) sensor are yet to be explored in detail. In this study, the effect of film thickness for skin te...

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Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin

Abstract: Stretchable, wireless health monitoring patches to evaluate heart rate, blood oximetry, UV exposure, and skin coloration.

Cited by 355 publications

References 28 publications

A skin-attachable, stretchable integrated system based on liquid GaInSn for wireless human motion monitoring with multi-site sensing capabilities

A skin-attachable, stretchable integrated system based on liquid GaInSn for wireless human motion monitoring with multi-site sensing capabilities

Epilepsy Treatment: A Futurist View

Efficient Skin Temperature Sensor and Stable Gel‐Less Sticky ECG Sensor for a Wearable Flexible Healthcare Patch

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