High performance flexible pH sensor based on polyaniline nanopillar array electrode

Yoon, Jo Hee; Hong, Seongkweon; Yun, Seok-Oh; Lee, Seok Jae; Lee, Tae Jae; Lee, Kyoung G.; Choi, Bong Gill

doi:10.1016/j.jcis.2016.11.033

Cited by 97 publications

(66 citation statements)

References 33 publications

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“…While conventional glass-type electrodes have been widely used for pH measurement, for integration with wearables, they possess several disadvantages due to their size constraint, rigidity and need for electrode maintanence. More recently, pH-responsive polymers have been developed [23] [24]. These polymers can be readily integrated with wearables due to their flexible nature, ease of miniaturization, and good biocompatibility.…”

Section: Design Fabrication and Evaluation Of Polyaniline (Pani) Sensormentioning

confidence: 99%

pH Watch - Leveraging Pulse Oximeters in Existing Wearables for Reusable, Real-time Monitoring of pH in Sweat

Balaji

Chen

Wang

et al. 2019

Proceedings of the 17th Annual International Conference on Mobile Systems, Applications, and Services

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Sweat is a readily accessible bodily fluid for detecting biomarkers such as pH, glucose etc., enabling continuous and non-invasive assessment of the well-being of individuals. Our proposed work aims at leveraging pulse oximeter chips in current-day fitness trackers for real-time continuous monitoring of pH in sweat. We achieve that by fabricating a highly responsive and long-term reusable pH sweat sensor on a flexible material to achieve skin conformity, targeting the sensor to work at the reflected infrared (880nm) and red (660nm) photoplethysmograph (PPG) signal intensities recorded by pulse oximeters. The sensor can be readily mounted atop any wearable with a pulse oximeter. We have successfully demonstrated a low-cost, low-power, highly-responsive and longterm reusable wrist-worn wearable prototype, pH Watch, for realtime continuous monitoring of pH value of sweat. We conducted on-body trials with 10 participants and pH Watch achieves an accuracy of ≈91%. We also showed that the integration of our sweat sensor does not hinder the pulse oximeter from measuring heart rate and SpO 2 , and users can continue with their daily activities with motion artifacts removed efficiently from PPG signals using the TROIKA framework, resulting in heart rate and SpO 2 measurements with an accuracy of ≈95% and ≈96% respectively when validated against commercial finger pulse oximeter measurements. To the best of our knowledge, pH Watch is the first demonstration of a reusable sweat sensor that can be readily integrated into today's smart watches with pulse oximeters, paving the way for ubiquitous sensing of biomarkers. * Both authors contributed equally to this research.• Human-centered computing → Ubiquitous and mobile devices; • Applied computing → Health care information systems.

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Section: Design Fabrication and Evaluation Of Polyaniline (Pani) Sensormentioning

confidence: 99%

pH Watch - Leveraging Pulse Oximeters in Existing Wearables for Reusable, Real-time Monitoring of pH in Sweat

Balaji

Chen

Wang

et al. 2019

Proceedings of the 17th Annual International Conference on Mobile Systems, Applications, and Services

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“…A potential pH sensor that could integrated into a dressing was described by Yoon et al [ 128 ]. A matrix of nanopillars (mixture of polyurethane acrylate and NOA63, diameter about 400 nm) was fabricated on a PET substrate.…”

Section: Sensors For Temperature and Phmentioning

confidence: 99%

“… ( a ) An example of a flexible PAN pH sensor with ( b ) sensor dimensions; ( c , d ) SEM images of the PAN sensor (Reprinted with permission from [ 128 ]); ( e ) examples of the pH (left) and temperature (right) screen-printed sensors to use in direct contact with a wound (Reprinted with permission from [ 120 ]). …”

Section: Figurementioning

confidence: 99%

Sensors and Biosensors for C-Reactive Protein, Temperature and pH, and Their Applications for Monitoring Wound Healing: A Review

Salvo

Dini

Kirchhain

et al. 2017

Sensors

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Wound assessment is usually performed in hospitals or specialized labs. However, since patients spend most of their time at home, a remote real time wound monitoring would help providing a better care and improving the healing rate. This review describes the advances in sensors and biosensors for monitoring the concentration of C-reactive protein (CRP), temperature and pH in wounds. These three parameters can be used as qualitative biomarkers to assess the wound status and the effectiveness of therapy. CRP biosensors can be classified in: (a) field effect transistors, (b) optical immunosensors based on surface plasmon resonance, total internal reflection, fluorescence and chemiluminescence, (c) electrochemical sensors based on potentiometry, amperometry, and electrochemical impedance, and (d) piezoresistive sensors, such as quartz crystal microbalances and microcantilevers. The last section reports the most recent developments for wearable non-invasive temperature and pH sensors suitable for wound monitoring.

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“…Additionally, based on its structural properties such as a high aspect ratio, a huge number of captured molecules can be stably immobilized on the nanostructure, which generates plenty of electrons; thus, we effectively obtained the increased signal via nanostructural manipulation on thin film. Based on these advantages, nanopillar structure is favorable for the analysis of biomarkers present at low levels in body fluids [30,32].…”

Section: Introductionmentioning

confidence: 99%

Flexible nanopillar-based immunoelectrochemical biosensor for noninvasive detection of Amyloid beta

et al. 2020

Self Cite

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The noninvasive early detection of biomarkers for Alzheimer's disease (AD) is essential for the development of specific treatment strategies. This paper proposes an advanced method for fabricating highly ordered and flexible nanopillarbased electrochemical biosensors by the combination of soft/photolithography and metal evaporation. The nanopillar array (NPA) exhibits high surface area containing 1500 nm height and 500 nm diameter with 3:1 ratio. In regard with physical properties of polyurethane (PU) substrate, the developed NPA is sustainable and durable to external pressure such as bending and twisting. To manipulate the NPA surface to biocompatible, the gold was uniformly deposited on the PU substrate. The thiol chemistry which is stably modified on the gold surface as a form of selfassembled monolayer was employed for fabricating the NPA as a biocompatible chip by covalently immobilize the antibodies. The proposed nanopillar-based immunoelectrochemical biosensor exhibited good and stable electrochemical performance in β-amyloid (Aβ) detection. Moreover, we successfully confirmed the performance of the as-developed sensor using the artificial injection of Aβ in human tear, with sensitivity of 0.14 ng/mL and high reproducibility (as a standard deviation below 10%). Our findings show that the developed nanopillar-based sensor exhibits reliable electrochemical characteristics and prove its potential for application as a biosensor platform for testing at the point of care.

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High performance flexible pH sensor based on polyaniline nanopillar array electrode

Cited by 97 publications

References 33 publications

pH Watch - Leveraging Pulse Oximeters in Existing Wearables for Reusable, Real-time Monitoring of pH in Sweat

pH Watch - Leveraging Pulse Oximeters in Existing Wearables for Reusable, Real-time Monitoring of pH in Sweat

Sensors and Biosensors for C-Reactive Protein, Temperature and pH, and Their Applications for Monitoring Wound Healing: A Review

Flexible nanopillar-based immunoelectrochemical biosensor for noninvasive detection of Amyloid beta

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