Browsing by Author "Wang, Shi-Wei"

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A CMOS Capacitive Dopamine Sensor with Sub-nM Detection Resolution
(2009)
Wang, Shi-Wei
;
Lin, Chih-Heng
;
Yang, Yuh-Shyong
;
Lu, Michael S. -C.
;
生物科技學系
Interdigitated microelectrodes integrated with CMOS sensing circuitry are presented in this work for detection of the neurotransmitter dopamine and as an immunosensor with sensitivity enhanced by gold nanoparticles. Microelectrodes covered by the silicon dioxide layer are fabricated through a maskless post-CMOS process. Charged biomolecules bind to the functionalized oxide surface after immobilization, producing a capacitive change for the underlying electrodes. Three electrode designs with gaps from 0.5 mu m to 1 mu m and capacitance values from 13 fF to 925 IF are tested. The capacitance increases with respect to the concentrations of nanoparticle and dopamine. The minimum detectable concentration of dopamine is 540 pM at a 1-Hz bandwidth.
An electrochemical dopamine sensor with a CMOS detection circuit
(2008-07-01)
Chan, Feng-Lin
;
Chang, Wen-Ying
;
Kuo, Li-Min
;
Lin, Chih-Heng
;
Wang, Shi-Wei
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).
An electrochemical dopamine sensor with CMOS detection circuit
(2007-01-01)
Zhan, Feng-Lin
;
Kuo, Li-Min
;
Wang, Shi-Wei
;
Lu, Michael S. -C.
;
Chang, Wen-Ying
This paper presents the use of interdigitated microelectrodes as the platform for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with gaps ranging between 3 gm to 7 gm are fabricated by the lift-off technique. The reduction and oxidation potentials for dopamine are determined by voltammetry using the fabricated microelectrodes. A CMOS sensing circuit is used to amplify the electrochemical current produced by the working electrodes. Experimental result shows that for a dopamine concentration of 10 mu M the measured current value is 11 pA.