An electrochemical dopamine sensor with a CMOS detection circuit

This paper presents the integration of interdigitated microelectrodes and a CMOS circuit for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with a gap of 3 mu m are fabricated by the lift-off technique. The CMOS sensing circuit has a current gain of 10, an integrating capacitor of 4 pF, and a measured dynamic range of 60 dB. The applied reduction and oxidation potentials are determined by voltammetry at about -0.2 V and 0.6 V, respectively. The measured collection efficiency can reach up to 84%. The produced oxidation current with respect to dopamine concentration averages 0.44 nA mu M-1.