DocumentCode :
1506106
Title :
Wireless Intraocular Pressure Sensing Using Microfabricated Minimally Invasive Flexible-Coiled LC Sensor Implant
Author :
Chen, Po-Jui ; Saati, Saloomeh ; Varma, Rohit ; Humayun, Mark S. ; Tai, Yu-Chong
Author_Institution :
Dept. of Electr. Eng., California Inst. of Technol., Pasadena, CA, USA
Volume :
19
Issue :
4
fYear :
2010
Firstpage :
721
Lastpage :
734
Abstract :
This paper presents an implant-based wireless pressure sensing paradigm for long-range continuous intraocular pressure (IOP) monitoring of glaucoma patients. An implantable parylene-based pressure sensor has been developed, featuring an electrical LC-tank resonant circuit for passive wireless sensing without power consumption on the implanted site. The sensor is microfabricated with the use of parylene C (poly-chloro-p-xylylene) to create a flexible coil substrate that can be folded for smaller physical form factor so as to achieve minimally invasive implantation, while stretched back without damage for enhanced inductive sensor-reader coil coupling so as to achieve strong sensing signal. A data-processed external readout method has also been developed to support pressure measurements. By incorporating the LC sensor and the readout method, wireless pressure sensing with 1-mmHg resolution in longer than 2-cm distance is successfully demonstrated. Other than extensive on-bench characterization, device testing through six-month chronic in vivo and acute ex vivo animal studies has verified the feasibility and efficacy of the sensor implant in the surgical aspect, including robust fixation and long-term biocompatibility in the intraocular environment. With meeting specifications of practical wireless pressure sensing and further reader development, this sensing methodology is promising for continuous, convenient, direct, and faithful IOP monitoring.
Keywords :
biomedical measurement; diseases; eye; pressure measurement; pressure sensors; prosthetics; vision defects; biocompatibility; electrical LC-tank resonant circuit; glaucoma; microfabrication; minimally invasive flexible-coiled LC sensor; minimally invasive implantation; parylene C (poly-chloro-p-xylylene); parylene-based pressure sensor; readout method; wireless intraocular pressure sensing; Implantable microdevice; LC pressure sensor; intraocular pressure (IOP); parylene; wireless sensing;
fLanguage :
English
Journal_Title :
Microelectromechanical Systems, Journal of
Publisher :
ieee
ISSN :
1057-7157
Type :
jour
DOI :
10.1109/JMEMS.2010.2049825
Filename :
5475197
Link To Document :
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