health+monitoring
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New Liquid Metal Wearable Pressure Sensor Created for Health Monitoring Applications
Soft pressure sensors have received significant research attention in a variety of fields, including soft robotics, electronic skin, and wearable electronics. Wearable soft pressure sensors have great potential for the real-time health monitoring and for the early diagnosis of diseases.
A KAIST research team led by Professor Inkyu Park from the Department of Mechanical Engineering developed a highly sensitive wearable pressure sensor for health monitoring applications. This work was reported in Advanced Healthcare Materials on November 21 as a front cover article.
This technology is capable of sensitive, precise, and continuous measurement of physiological and physical signals and shows great potential for health monitoring applications and the early diagnosis of diseases.
A soft pressure sensor is required to have high compliance, high sensitivity, low cost, long-term performance stability, and environmental stability in order to be employed for continuous health monitoring. Conventional solid-state soft pressure sensors using functional materials including carbon nanotubes and graphene have showed great sensing performance. However, these sensors suffer from limited stretchability, signal drifting, and long-term instability due to the distance between the stretchable substrate and the functional materials.
To overcome these issues, liquid-state electronics using liquid metal have been introduced for various wearable applications. Of these materials, Galinstan, a eutectic metal alloy of gallium, indium, and tin, has great mechanical and electrical properties that can be employed in wearable applications. But today’s liquid metal-based pressure sensors have low-pressure sensitivity, limiting their applicability for health monitoring devices.
The research team developed a 3D-printed rigid microbump array-integrated, liquid metal-based soft pressure sensor. With the help of 3D printing, the integration of a rigid microbump array and the master mold for a liquid metal microchannel could be achieved simultaneously, reducing the complexity of the manufacturing process. Through the integration of the rigid microbump and the microchannel, the new pressure sensor has an extremely low detection limit and enhanced pressure sensitivity compared to previously reported liquid metal-based pressure sensors. The proposed sensor also has a negligible signal drift over 10,000 cycles of pressure, bending, and stretching and exhibited excellent stability when subjected to various environmental conditions.
These performance outcomes make it an excellent sensor for various health monitoring devices. First, the research team demonstrated a wearable wristband device that can continuously monitor one’s pulse during exercise and be employed in a noninvasive cuffless BP monitoring system based on PTT calculations. Then, they introduced a wireless wearable heel pressure monitoring system that integrates three 3D-BLiPS with a wireless communication module.
Professor Park said, “It was possible to measure health indicators including pulse and blood pressure continuously as well as pressure of body parts using our proposed soft pressure sensor. We expect it to be used in health care applications, such as the prevention and the monitoring of the pressure-driven diseases such as pressure ulcers in the near future. There will be more opportunities for future research including a whole-body pressure monitoring system related to other physical parameters.”
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT.
< Figure 1. The front cover image of Advanced Healthcare Materials, Volume 8, Issue 22. >
< Figure 2. Highly sensitive liquid metal-based soft pressure sensor integrated with 3D-printed microbump array. >
< Figure 3. High pressure sensitivity and reliable sensing performances of the proposed sensor and wireless heel pressure monitoring application. >
-ProfileProfessor Inkyu ParkMicro/Nano Transducers Laboratoryhttp://mintlab1.kaist.ac.kr/
Department of Mechanical EngineeringKAIST
2019.12.20 View 11914 -
Professor Son Hoon received "Structural Health Monitoring Person of the Year Award."
Professor Son Hoon (42) of the Department of Civil and Environmental Engineering received the “Structural Health Monitoring Person of the Year Award” at an international workshop on structural health monitoring held in Stanford University.
The award is given by the editor and advisors of prestigious international magazine, “Journal of Structural Health Monitoring,” to a researcher with the best research record in a year. Professor Son has published 42 SCI level dissertations, registered 17 patents both domestically and internationally, and presented over 100 papers in international journals, for which he was recognized with the award. Professor Son is the first Korean who receives this award.
One of the most significant achievements by Professor Son was “reference-free damage diagnosis” that he had developed in 2007. The diagnosis allows for the detection of wear and tear of a structure without having to use the foundation signal from the initial stages of the structure. The diagnosis contributed greatly in increasing the reliability of the signal information received from smart sensors attached to the structure by eliminating the environmental impact like temperature.
Professor Son is currently working on green energy structural health monitoring system development related projects. His current work deals with airplanes, bridges, nuclear facilities, high speed railways, wind turbines, and etc. in cooperation with Boeing, United States Air Force Research Institute, Korea Research Foundation, Ministry of Defense Research Institute, Korea Expressway Corporation, POSCO, and etc.
In addition, Professor Son successfully adopted a local monitoring method using smart piezoelectric sensors on a bridge in New Jersey as part of the Long Term Bridge Performance Program initiated by the National Highway Bureau. The success was even introduced in New Jersey’s public TV and newspaper agencies.
Professor Son was given tenure at a record age of 39 in 2008 and received numerous awards given out by the Ministry of Education and Science and international organizations like the ‘Edward M Curtis’ Professor Award from Purdue University.
2011.10.10 View 9967