The objective of this research is to develop high-sensitive light-weight accelerometers that can be body-worn like a bandage or vest for continuous respiratory sound monitoring. The approach is based on a novel air-spaced cantilever structure to increase the accelerometer sensitivity by orders of magnitude and a unique intelligent textile technology to make the packaged accelerometer light-weight and wearable. The proposed research may lead to a paradigm shift in the monitoring of respiratory sounds and advance the development of various wearable health monitoring sensors. The novel air-spaced cantilever structures proposed may enable high-performance and low-cost accelerometers that are highly desirable for many industrial, scientific, civilian and military applications. The successful development of the proposed system will have significant impacts on various clinical and healthcare applications such as anesthesia monitoring in operating rooms, asthma management, non-invasive vital sign monitoring for pilots and other military personnel, patient monitoring in intensive care units, nursing facilities, and emergency medical services, etc. Significant societal and economic impacts are expected. The exciting new methods and findings associated with the research will be first incorporated into a Micro/Nano Electro Mechanical Systems course the PI is teaching. Then a new course on wearable physiological sensors will be developed. Eventually, a unique graduate level education program on wearable health monitoring will be developed. Both undergraduate and high school students will be involved in the proposed research work. By taking advantage of the geographic location of Wayne State University, the PI is committed to broaden the participation of underrepresented groups.
The scientific objective of this proposal is to develop high-performance sensors that can be body-worn for continuous respiratory and heart sound monitoring. Toward this objective, we have successfully developed a number of novel enabling technologies. First, an asymmetrically gapped cantilever structure has been developed to significantly increase strain sensitivity. The microfabrication of high-performance accelerometers based on this novel structure has been demonstrated. We have also constructed meso-scale accelerometers based on the piezoelectric asymmetric-gapped cantilever structure. The continuous detection of heart and lung sounds on both healthy and diseased subjects has been successfully demonstrated. We further proved the feasibility of unobtrusive and unattended cardiovascular monitoring from ultra-sensitive accelerometers mounted on beds and chairs. Second, we invented a smart skin technology and a smart yarn technology with the unique advantage of being compatible with main-stream CMOS (Complementary Metal-Oxide-Semiconductor) and MEMS (Micro Electro Mechanical System) processes. Therefore, silicon based high-performance CMOS circuits, MEMS devices, and sensors can be monolithically integrated into flexible substrates and yarns, greatly enhancing their performance and functionality. This research is expected to benefit society significantly. The wearable accelerometers developed will enable continuous heart and lung sound monitoring which can promptly provide critical information for disease diagnosis and heath monitoring, such as monitoring of heart failure patients, patient monitoring in operating rooms (ORs)/intensive care units (ICUs) and nursing facilities, sleep disorder studies, and asthma monitoring. The unobtrusive cardiovascular monitoring from beds and chairs we have recently demonstrated may have a significant impact on ubiquitous healthcare due to its low-cost, convenience, and unattended nature. The smart skin and smart yarn technologies will have great impact on wearable electronics and wearable health monitoring devices, thanks to their ability to integrate silicon based high-performance CMOS circuits, MEMS devices, and sensors. This research has trained three Ph.D. students, two postdoctoral researchers, and many undergraduates, including members of underrepresented groups. Outreach activities that involve high school students have also been carried out. The research results have been reported in six journal publications and presented in numerous conferences and workshops. The results of this NSF award have been posted on Prof. Xu’s website and incorporated into ECE 5575 (Introduction to Micro/Nano Electro Mechanical Systems), a class Prof. Xu developed at Wayne State University.
