KEIO RESEARCHERS INFORMATION SYSTEM

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Papers 【 Display / hide 】

• 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

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  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

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  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.

  • Access to Document (DOI)

• 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

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  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).

  • Access to Document (DOI)

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