Multimodal epidermal devices for hydration monitoring

Krishnan, Siddharth; Shi, Yunzhou; Webb, R. Chad; Ma, Yinji; Bastien, Philippe; Crawford, Kaitlyn E.; Wang, Charles; Feng, Xue; Manco, Megan; Kurniawan, Jonas; Tir, Edward; Balooch, Guive; Pielak, Rafal M.; Rogers, John A.

doi:10.1038/micronano.2017.14

Cited by 53 publications

(68 citation statements)

References 43 publications

(65 reference statements)

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“…Skin hydration can be reflected by either electrical resistance/impedance or thermal conductivity11d,19 of the skin. NFC‐enabled battery‐free skin hydration e‐tattoos are reported very recently,11d but the overall tattoo is not stretchable and skin hydration is inferred from measured skin thermal conductivity.…”

Section: Resultsmentioning

confidence: 99%

Modular and Reconfigurable Wireless E‐Tattoos for Personalized Sensing

Jeong

Wang

et al. 2019

Adv Materials Technologies

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telemedicine, mobile health, prosthetics, athletic training, human-machine interface (HMI) and so on. From "skin-like" electronics (a.k.a. e-skins) [1] to "epidermal electronics" (a.k.a. e-tattoos), [2] people are hopeful that the emerging flexible/ stretchable electronics technologies will disrupt the wearable industry. Specifically, e-tattoos are ultrathin, ultrasoft membranes that can well conform to the skin to monitor a variety of biomarkers including electrophysiology, [3] mechanoacoustic signals, [4] skin temperature, [5] skin hydration, [6] skin stiffness, [7] blood pressure, [8] blood oxygen saturation, [9] and even sweat analytes. [10] Wireless communication enabled by near field communication (NFC) [9a,11] and Bluetooth [12] have also been demonstrated in a few recent e-tattoos. However, which biomarker to measure is highly personal and may vary from time to time for the same individual. Moreover, different biomarkers should be measured at different locations using different types of sensors and read-out circuits. Even if one can build a multimodal e-tattoo, excessive recordings not personalized to the user may cause unnecessary power and bandwidth consumption, which is a major concern for wireless wearables. Although it is possible to build specific e-tattoos for specific sensing tasks, it would be a big waste of the wireless transmission and read-out circuits if the whole e-tattoo has to be disposed after just one use.Herein, we propose a possible remedy for all the aforementioned challenges-the modular and reconfigurable e-tattoos, where layers of distinct functionalities (e.g., NFC layer, analog front end (AFE) layer, electrode layer, etc.) can be pre-fabricated as building blocks that can be picked and assembled into customized e-tattoos and can also be swapped out to form new e-tattoos. Electrical connections between the layers can be achieved through aligned vias. Compared with existing monolayer, fully pre-defined e-tattoos, the newly proposed modular and reconfigurable e-tattoos would have the following appealing advantages. First, the multilayer stack can effectively shrink the footprint of the e-tattoo on the skin, especially when numerous components and complex circuits are needed for signal read-out and wireless transmission. Second, when the measurement is done, only the passive electrode/sensor layer that has been in direct contact with the skin needs to be peeled off from the e-tattoo and disposed. As a result, the leftover NFC In the past few years, ultrathin and ultrasoft epidermal electronics (a.k.a. e-tattoos) emerged as the next-generation wearables for telemedicine, mobile health, performance tracking, human-machine interface (HMI), and so on. However, it is not possible to build an all-purpose e-tattoo that can accommodate such a wide range of applications. Thus, the design, fabrication, and validation of modular and reconfigurable wireless e-tattoos for personalized sensing are reported. Such e-tattoos feature a multilayer stack of stretchable layers of distinct function...

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Section: Resultsmentioning

confidence: 99%

Modular and Reconfigurable Wireless E‐Tattoos for Personalized Sensing

Jeong

Wang

et al. 2019

Adv Materials Technologies

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“…Prior to this, evaluations of the state of SC water and characterisation of SC water types were only possible using DSC, which remains the standard but involves complex and time-consuming procedures, and only feasible for ex vivo measurements. Furthermore, emerging techniques such as multimodal sensors of skin hydration [254][255][256] claim to offer "skin-like" devices that integrate with skin without application of pressure for real-time, in vivo hydration assessment but these remain in early research.…”

Section: Discussionmentioning

confidence: 99%

Review of Modern Techniques for the Assessment of Skin Hydration

Qassem

Kyriacou

2019

Cosmetics

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Skin hydration is a complex process that influences the physical and mechanical properties of skin. Various technologies have emerged over the years to assess this parameter, with the current standard being electrical probe-based instruments. Nevertheless, their inability to provide detailed information has prompted the use of sophisticated spectroscopic and imaging methodologies, which are capable of in-depth skin analysis that includes structural and composition details. Modern imaging and spectroscopic techniques have transformed skin research in the dermatological and cosmetics disciplines, and are now commonly employed in conjunction with traditional methods for comprehensive assessment of both healthy and pathological skin. This article reviews current techniques employed in measuring skin hydration, and gives an account on their principle of operation and applications in skin-related research.

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“…Other parameters in the model include the thermal conductivity (k skin = 0.3 W/m-K 35 ), density (ρ skin = 1050 Kg/m 3 49 ) and heat capacity (C p,skin = J/Kg-K 35 ) of the skin, and corresponding properties for the shunt (k shunt = 0.21 W/m-K, ρ shunt = 965 Kg/m 3 , C p,shunt = 1460 J/Kg-K 50 ). While the constitutive and geometrical properties of the shunt are largely known and fixed, h skin , k skin , ρ skin , and C p,skin can vary from patient to patient, across a well-characterized 35,51 range. The effects of each of these parameters are discussed elsewhere 30 .…”

Section: Conversion Of Thermal Anisotropy To Quantitative Flow Ratementioning

confidence: 99%

“…Our recent work focuses on the development of a class of wearable, wireless sensor designed to address this unmet need. Here, measurements of flow follow from localized thermal actuation and sensing 30 using a soft, thin device [31][32][33][34][35] gently laminated onto the surface of the skin at the location of the shunt. The results presented in the following extend these concepts into a user-friendly, fully wireless system that enables continuous, noninvasive monitoring of CSF flow performed by patients themselves in real-world settings.…”

Section: Introductionmentioning

confidence: 99%

Continuous, noninvasive wireless monitoring of flow of cerebrospinal fluid through shunts in patients with hydrocephalus

et al. 2020

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Hydrocephalus is a common disorder caused by the buildup of cerebrospinal fluid (CSF) in the brain. Treatment typically involves the surgical implantation of a pressure-regulated silicone tube assembly, known as a shunt. Unfortunately, shunts have extremely high failure rates and diagnosing shunt malfunction is challenging due to a combination of vague symptoms and a lack of a convenient means to monitor flow. Here, we introduce a wireless, wearable device that enables precise measurements of CSF flow, continuously or intermittently, in hospitals, laboratories or even in home settings. The technology exploits measurements of thermal transport through near-surface layers of skin to assess flow, with a soft, flexible, and skin-conformal device that can be constructed using commercially available components. Systematic benchtop studies and numerical simulations highlight all of the key considerations. Measurements on 7 patients establish high levels of functionality, with data that reveal time dependent changes in flow associated with positional and inertial effects on the body. Taken together, the results suggest a significant advance in monitoring capabilities for patients with shunted hydrocephalus, with potential for practical use across a range of settings and circumstances, and additional utility for research purposes in studies of CSF hydrodynamics.

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Multimodal epidermal devices for hydration monitoring

Cited by 53 publications

References 43 publications

Modular and Reconfigurable Wireless E‐Tattoos for Personalized Sensing

Modular and Reconfigurable Wireless E‐Tattoos for Personalized Sensing

Review of Modern Techniques for the Assessment of Skin Hydration

Continuous, noninvasive wireless monitoring of flow of cerebrospinal fluid through shunts in patients with hydrocephalus

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