Social innovation
Medical & healthcare, Drug development, Security

Wireless and batteryless MEMS resonator sensors
Division of Precision Engineering and Applied Physics, Graduate School of Engineering
Professor Hirotsugu Ogi
https://researchmap.jp/read0042771

Abstract
The goal of this project is to establish a resonator sensor systemthat can be used not only for diagnosis but also for a wide rangeof applications such as gas sensing in inaccessible areas, healthmonitoring of infrastructures, and long-term biological signal monitoring in living animals, based on a new measurement concept ofsemi-permanent measurement.

nuclear power plants and other locations where human access isdifficult as well as the semi-permanent nondestructive evaluation ofinternal stress of infrastructures by embedding the sensors in them,contributing to a safe, secure, and healthy society.

Social innovation▍ Background & Results
Early diagnosis is extremely important for cancer, neurodegenerative diseases, and viral diseases, resulting in a huge reduction
in medical costs. In addition, the realization of a carbon neutral
society is highly expected, requiring the advancement of related
technologies. The importance of hydrogen as a decarbonizedenergy source is well understood, but its explosive nature is also
recognized, and it is particularly important to improve the performance of hydrogen gas sensors, especially for battery-free measurement in inaccessible locations such as nuclear power plants.
In addition, aging of infrastructure has become a serious problem
in many countries, and development of such a device that can remotely evaluate stresses inside structures without power supply will
greatly contribute to monitoring the health of social infrastructure
structures. Thus, a sensing technology that is highly sensitive, wireless, and batteryless is eagerly awaited in the realization of a safe,secure, and healthy society. We consider that only the resonatorsensor will satisfy these demands.
The resonator sensor detects various properties through thechange in the resonant frequency of the microbell (resonator) as
shown in Fig. 1. Capturing target materials on the resonator surface increases the effective mass of the resonator system anddecreases the resonant frequency. This principle can be used as alabel-free biosensor (upper left). When the shape of the resonator
is changed by an external force, the resonant frequency changes.
This phenomenon can be used as a stress sensor (bottom left). If
resonator’s elastic constants are sensitive to temperature, it can beused as a temperature sensor because the resonance frequencychanges with temperature change (upper right). When a target
gas is adsorbed on the sensor film deposited on the resonator,
bending deformation occurs due to the generation of the surface
force, which also changes the resonance frequency. This principle
can be used as a gas sensor (bottom right). For example, Figure 2
shows the response of originally developed MEMS resonator sensor for hydrogen-gas detection, which can detect hydrogen gas at
extremely low concentrations of 1 ppm.

Figure 1 Applications of the oscillator sensor.

Figure 2 Hydrogen-gas detection by the MEMS oscillator sensor.

▍ Significance of the research and Future perspective
Our original sensing technology makes it possible to achieve
not only ultra-sensitive detection of targets, but also batterylessand long-distance sensing of various targets: It will conduct thesemi-permanent measurement of hydrogen gas concentration at

P a t e n t Japanese Patent No. 4981998, Japanese Unexamined Patent Publication No. 2021-131315, 2019-138628
Lianjie, Zhou et al. MEMS hydrogen gas sensor with wireless quartz crystal resonator, Sens. Actuat. B. 334, 129651 (2021).
doi: 10.1016/j.snb.2021.129651
T r e a t i s e Noi, Kentaro et al. Disaggregation behavior of amyloid β fibrils by anthocyanins studied by total-internal-reflection-fluorescence microscopy coupled withwireless quartz-crystal microbalance biosensor, Anal. Chem. 93, 11176-11183 (2021). doi: 10.1021/acs.analchem.1c01720
Noi, Kentaro et al. Ultrahigh-Frequency Wireless MEMS QCM Biosensor for Direct Label-Free Detection of Biomarkers in a Large Amount ofContaminants, Anal. Chem. 91(15), 9398-9402 (2019). doi: 10.1021/acs.analchem.9b01414
URLK e y w o r d QCM, wireless, batteryless, biosensor, gas sensor