A hydrogel-based wireless chemical sensor

Ming Lei, Antonio Baldi, Tingrui Pan, Yuandong Gu, Ronald A Siegel, Babak Ziaie

Research output: Contribution to journalConference articlepeer-review

20 Scopus citations


In this paper, we report on the fabrication and characterization of a new hydrogel-based wireless chemical sensor. The basic device structure is a passive LC resonator coupled to a stimuli-sensitive hydrogel which is confined between a stiff porous membrane and a thin glass diaphragm. As small molecules pass through the porous membrane, hydrogel swells and deflects the flexible glass diaphragm which is the movable plate of the variable capacitor in the totally integrated passive LC resonator. The corresponding change in resonant frequency can be remotely detected. pH-sensitive hydrogels were loaded and tested with the measured sensitivity of 394 kHz/pH at the pH of 7.4. The swelling pressure of the confined hydrogel was also determined using the calibration curve with applied air pressure.

Original languageEnglish (US)
Pages (from-to)391-394
Number of pages4
JournalProceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)
StatePublished - 2004
Event17th IEEE International Conference on Micro Electro Mechanical Systems (MEMS): Maastricht MEMS 2004 Technical Digest - Maastricht, Netherlands
Duration: Jan 25 2004Jan 29 2004


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