A Sensor Interface for Neurochemical Signal Acquisition

This paper describes the design of an integrated sensor interface for neurochemical signal acquisition. Neurochemicals undergo oxidation and reduction reactions in the presence of an action potential. Thus, knowledge of the oxidation and reduction potentials of neurochemicals is important in the neurostimulation treatment of neurological and neurodegenerative diseases. The sensor interface circuit utilizes a mixed-signal design to detect the induced current from the neurochemical, in response to an applied voltage. The circuit is fabricated in 65nm CMOS technology and supports a wide input current range of ±1.2µA with a current resolution of 85.4pA, enabling detection of neurochemicals within the supported current range. Measured results with dopamine concentration of 500nMol demonstrate the ability of the sensor interface circuit to detect oxidation and reduction current peaks, indicating the release times and the required oxidation and reduction potentials for neurostimulation of the neurochemical.