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Microfabricated Implantable Parylene-Based Wireless Passive Intraocular Pressure Sensors

Chen, Po-Jui and Rodger, Damien C. and Saati, Saloomeh and Humayun, Mark S. and Tai, Yu-Chong (2008) Microfabricated Implantable Parylene-Based Wireless Passive Intraocular Pressure Sensors. Journal of Microelectromechanical Systems, 17 (6). pp. 1342-1351. ISSN 1057-7157. doi:10.1109/JMEMS.2008.2004945.

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This paper presents an implantable parylene-based wireless pressure sensor for biomedical pressure sensing applications specifically designed for continuous intraocular pressure (IOP) monitoring in glaucoma patients. It has an electrical LC tank resonant circuit formed by an integrated capacitor and an inductor coil to facilitate passive wireless sensing using an external interrogating coil connected to a readout unit. Two surface-micromachined sensor designs incorporating variable capacitor and variable capacitor/inductor resonant circuits have been implemented to realize the pressure-sensitive components. The sensor is monolithically microfabricated by exploiting parylene as a biocompatible structural material in a suitable form factor for minimally invasive intraocular implantation. Pressure responses of the microsensor have been characterized to demonstrate its high pressure sensitivity (> 7000 ppm/mmHg) in both sensor designs, which confirms the feasibility of pressure sensing with smaller than 1 mmHg of resolution for practical biomedical applications. A six-month animal study verifies the in vivo bioefficacy and biostability of the implant in the intraocular environment with no surgical or postoperative complications. Preliminary ex vivo experimental results verify the IOP sensing feasibility of such device. This sensor will ultimately be implanted at the pars plana or on the iris of the eye to fulfill continuous, convenient, direct, and faithful IOP monitoring.

Item Type:Article
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URLURL TypeDescription
Rodger, Damien C.0000-0002-1583-5946
Humayun, Mark S.0000-0002-5830-5208
Tai, Yu-Chong0000-0001-8529-106X
Additional Information:© 2008 IEEE. Reprinted with permission. Manuscript received May 15, 2008; revised July 15, 2008. First published October 28, 2008; current version published December 4, 2008. This work was supported in part by the Engineering Research Centers Program of the National Science Foundation under Award EEC-0310723 and in part by Bausch and Lomb. An earlier version of this paper was presented at the 21st IEEE International Conference on Micro Electro Mechanical Systems, Tucson, AZ, January 13–17, 2008. Subject Editor S. Shoji. The authors would like to thank W. Li for her assistance on data acquisition of electrical impedance measurements, Dr. R. Agrawal and Dr. R. Varma for their valuable comments on surgical procedures, and T. Roper for his fabrication assistance.
Funding AgencyGrant Number
Bausch and LombUNSPECIFIED
Subject Keywords:Implantable microdevice; intraocular pressure (IOP); parylene; pressure sensor; wireless sensing
Issue or Number:6
Record Number:CaltechAUTHORS:CHEjmems08a
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12923
Deposited By: Archive Administrator
Deposited On:10 Jan 2009 00:02
Last Modified:08 Nov 2021 22:34

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