A new method of wirelessly transducing electrochemical impedance without integrated circuits or discrete electrical components was developed and characterized. The resonant frequency and impedance magnitude at resonance of a planar inductive coil is affected by the load on a secondary coil terminating in sensing electrodes exposed to solution (reflected impedance), allowing the transduction of the high-frequency electrochemical impedance between the two electrodes. Biocompatible, flexible secondary coils with sensing electrodes made from gold and Parylene C were microfabricated and the reflected impedance in response to phosphate-buffered saline solutions of varying concentrations was characterized.
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