Details of a Researcher - Miyamoto, Akihito

Papers - Miyamoto, Akihito

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Highly Precise, Continuous, Long-Term Monitoring of Skin Electrical Resistance by Nanomesh Electrodes

Miyamoto A., Kawasaki H., Lee S., Yokota T., Amagai M., Someya T.

Advanced Healthcare Materials (Advanced Healthcare Materials) 11 ( 10 ) 2022.05

ISSN 21922640

The transepidermal water loss has been widely used as a method for directly evaluating the barrier function of the stratum corneum of the skin. However, transepidermal water loss could not be measured continuously for a long period of time, and there were no reports of continuous monitoring of skin barrier functions. Here, a method is reported to continuously monitor the skin electrical resistance by nanomesh electrodes for a long period of time while maintaining the natural skin condition that does not inhibit water evaporation. Simultaneous measurements of the skin electrical resistance by nanomesh electrodes and transepidermal water loss exhibits a linear fit with a high negative correlation. Furthermore, dynamics of skin physiological functions are successfully visualized by monitoring of the skin electrical resistance by nanomesh electrodes for 30 h in daily life.

Access to Document (DOI)

Electronic functional member and strain sensor

T Someya, A Miyamoto, Y Wang, Y Matsuba, I Kawashima

US Patent App. 17/442,787 2022

Electronic functional member, method for manufacturing same, and biological measurement sensor

T Someya, A Miyamoto, Y Wang, S Lee, S Nagai, I Kawashima

US Patent App. 17/436,251 2022

Skin impedance measurements with nanomesh electrodes for monitoring skin hydration

R Matsukawa, A Miyamoto, T Yokota, T Someya

Advanced Healthcare Materials 9 (22), 2001322 (Advanced Healthcare Materials) 9 ( 22 ) 2020.11

ISSN 21922640

The importance of continuous monitoring of skin hydration in daily life, to aid in the diagnosis of skin diseases, is rising. Electrodes that can be worn directly on the skin are attracting attention as an effective means. However, they should not inhibit natural water evaporation from the skin and should not cause inflammation or irritation even if they are attached to the body for long periods of time. In this study, nanomesh electrodes that have previously been reported to exhibit high biocompatibility are also found to exhibit high water vapor permeability, resulting in properties that prevent skin dampness. Furthermore, the skin impedance measured using nanomesh electrodes is found to correlate with the hydration level of skin measured using existing medical equipment. This study provides a new approach to measure skin hydration in conditions close to bare skin.

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All-nanofiber-based, ultrasensitive, gas-permeable mechanoacoustic sensors for continuous long-term heart monitoring

Nayeem M.O.G., Lee S., Jin H., Matsuhisa N., Jinno H., Miyamoto A., Yokota T., Someya T.

Proceedings of the National Academy of Sciences of the United States of America (Proceedings of the National Academy of Sciences of the United States of America) 117 ( 13 ) 7063 - 7070 2020.03

ISSN 00278424

The prolonged and continuous monitoring of mechanoacoustic heart signals is essential for the early diagnosis of cardiovascular diseases. These bodily acoustics have low intensity and low frequency, and measuring them continuously for long periods requires ultrasensitive, lightweight, gas-permeable mechanoacoustic sensors. Here, we present an all-nanofiber mechanoacoustic sensor, which exhibits a sensitivity as high as 10,050.6 mV Pa-1 in the lowfrequency region (<500 Hz). The high sensitivity is achieved by the use of durable and ultrathin (2.5 μm) nanofiber electrode layers enabling a large vibration of the sensor during the application of sound waves. The sensor is ultralightweight, and the overall weight is as small as 5 mg or less. The devices are mechanically robust against bending, and show no degradation in performance even after 1,000- cycle bending. Finally, we demonstrate a continuous long-term (10 h) measurement of heart signals with a signal-to-noise ratio as high as 40.9 decibels (dB).

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Light-emitting device comprising flexible substrate and light-emitting element

H Iijima, A Miyamoto, K Sasai, Y Osada, M Izuchi

US Patent App. 16/686,254 2020

Light-emitting device comprising flexible substrate and light-emitting element

H Iijima, A Miyamoto, K Sasai, Y Osada, M Izuchi

US Patent 10,615,243 2020

Light-emitting device comprising flexible substrate and light-emitting element

H Iijima, A Miyamoto, K Sasai, Y Osada, M Izuchi

US Patent 9,991,326 2018

Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes

A Miyamoto, S Lee, NF Cooray, S Lee, M Mori, N Matsuhisa, H Jin, ...

Nature nanotechnology 12 (9), 907-913 (Nature Nanotechnology) 12 ( 9 ) 907 - 913 2017.09

ISSN 17483387

Thin-film electronic devices can be integrated with skin for health monitoring and/or for interfacing with machines. Minimal invasiveness is highly desirable when applying wearable electronics directly onto human skin. However, manufacturing such on-skin electronics on planar substrates results in limited gas permeability. Therefore, it is necessary to systematically investigate their long-term physiological and psychological effects. As a demonstration of substrate-free electronics, here we show the successful fabrication of inflammation-free, highly gas-permeable, ultrathin, lightweight and stretchable sensors that can be directly laminated onto human skin for long periods of time, realized with a conductive nanomesh structure. A one-week skin patch test revealed that the risk of inflammation caused by on-skin sensors can be significantly suppressed by using the nanomesh sensors. Furthermore, a wireless system that can detect touch, temperature and pressure is successfully demonstrated using a nanomesh with excellent mechanical durability. In addition, electromyogram recordings were successfully taken with minimal discomfort to the user.

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Thin film transistor, organic EL light emitting device, and method of fabricating thin film transistor

T Ukeda, A Miyamoto, N Nanai

US Patent 9,620,731 2017

Method for producing display panel, and display panel

N Nanai, T Ukeda, A Miyamoto

US Patent 9,312,283 2016

Electronic device and electronic device manufacturing method

A Miyamoto, Y Okumoto

US Patent 9,117,942 2015

Thin-film transistor element and method for producing same, organic el display element, and organic el display device