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Wireless Intraocular Pressure Sensing Using Microfabricated Minimally Invasive Flexible-Coiled LC Sensor Implant

Chen, Po-Jui and Saati, Saloomeh and Varma, Rohit and Humayun, Mark S. and Tai, Yu-Chong (2010) Wireless Intraocular Pressure Sensing Using Microfabricated Minimally Invasive Flexible-Coiled LC Sensor Implant. Journal of Microelectromechanical Systems, 19 (4). pp. 721-734. ISSN 1057-7157.

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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-chlorop- 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.

Item Type:Article
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Humayun, Mark S.0000-0002-5830-5208
Tai, Yu-Chong0000-0001-8529-106X
Additional Information:© 2010 IEEE. Manuscript received April 29, 2009; revised October 28, 2009; accepted April 21, 2010. Date of publication June 1, 2010; date of current version July 30, 2010. This work was supported in part by the Engineering Research Centers Program of the National Science Foundation (Award EEC-0310723) and in part by Bausch and Lomb. Subject Editor K. Najafi. The authors would like to thank W. Li for her assistance on data acquisition of electrical impedance measurements, D. C. Rodger for his assistance on surgical procedures and pressure sensing tests using animal models, and T. Roper for his assistance on sensor fabrication.
Funding AgencyGrant Number
NSF Engineering Research Centers ProgramEEC-0310723
Bausch and LombUNSPECIFIED
Subject Keywords:Implantable microdevice; intraocular pressure (IOP); LC pressure sensor; parylene; wireless sensing
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INSPEC Accession Number11494093
Issue or Number:4
Record Number:CaltechAUTHORS:20101117-094431583
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20848
Deposited By: Tony Diaz
Deposited On:17 Nov 2010 18:25
Last Modified:09 Mar 2020 13:18

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