Wireless Less-Invasive Blood Pressure Sensing Microsystem for Small Laboratory Animal In Vivo Real-Time Monitoring
演讲人: Prof. Darrin Young
Electrical Engineering and Computer Science Department
Case Western Reserve University
Cleveland, Ohio, USA
时间：2008年2月25日上午10：00（星期一）
地点：北京大学理科2号楼2736
A novel wireless less-invasive implantable blood pressure sensing system is developed for advanced biological research. The system employs a miniature instrumented elastic cuff, wrapped around a blood vessel, for small animal real-time blood pressure monitoring. The elastic cuff is made of bio-compatible soft silicone material by a molding process and is filled by insulating silicone oil with an immersed MEMS capacitive pressure sensor interfaced with low power integrated electronics. This technique avoids vessel penetration and substantially minimizes vessel restriction due to the soft cuff elasticity, thus attractive for long-term implant. The MEMS pressure sensor detects the coupled blood pressure waveform caused by the vessel expansion and contraction, followed by amplification, digitization, and wireless FSK data transmission to an external receiver. The integrated electronics are designed with capability of receiving RF power from an external power source and converting the RF signal to a stable 2V DC supply in an adaptive manner to power the overall implant system, thus enabling a realization of stand-alone battery-less implant microsystem. The electronics are fabricated in a 1.5 μm CMOS process and occupies an area of 2 mm x 2 mm. The prototype monitoring cuff is wrapped around the right carotid artery of a laboratory rat to measure real-time blood pressure waveform. The measured in vivo blood waveform is compared with a reference waveform recorded simultaneously by using a commercial catheter-tip transducer inserted into the left carotid artery. Two measured waveforms are closely matched with a constant scaling factor. The ASIC is interfaced with a 5 mm-diameter RF powering coil and four surface-mount components (one inductor and three capacitors) over a thin flexible substrate via bond wires, followed by silicone coating and packaging with the prototype blood pressure monitoring cuff. The overall system exhibits a weight of 280 mg, representing an order of magnitude mass reduction compared to state-of-the-art commercial technology.
About Prof. Darrin Young
Dr. Darrin Young received his BS, MS, and PhD degrees from the Department of Electrical Engineering and Computer Sciences at University of California at Berkeley in 1991, 1993, and 1999, respectively. At Berkeley he pioneered the research work in MEMS high-Q tunable capacitors and on-chip 3-D coil inductors for low-phase noise RF voltage-controlled oscillator design for wireless communication applications.
Between 1991 and 1993, he worked at Hewlett-Packard Laboratories in Palo Alto, California, where he designed a shared memory system for a DSP-based multiprocessor architecture. Between 1997 and 1998, he worked at Rockwell Semiconductor Systems in Newport Beach, California, where he designed silicon bipolar RF analog circuits for cellular telephony applications. During the same time frame, he was also at Lawrence Livermore National Laboratory, working on the design and fabrication of three-dimensional RF MEMS coil inductors for wireless communications.
Dr. Young joined the Department of Electrical Engineering and Computer Science at Case Western Reserve University in 1999, where he is currently an Associate Professor. His research interests include MEMS and nano-electro-mechanical devices design, fabrication, and integrated circuits design for biomedical implants, wireless sensing, powering, communications, and general industrial applications.
His research work is supported by National Science Foundation, National Institutes of Health, NASA, U.S. Army Research Office, Defense Advanced Research Project Agency, and U.S. Department of Veteran Affairs. He has published many technical papers in journals and conferences, and served as a technical program committee member, steering committee member, and session chair for a number of international conferences. Dr. Young is also an associate editor of the IEEE Journal of Solid-State Circuits.
