Browsing by Author "Lu, Michael S. -C."

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A CMOS Capacitive Dopamine Sensor with Sub-nM Detection Resolution
(2009)
Wang, Shi-Wei
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Lu, Michael S. -C.
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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 CMOS detection circuit
(2007-01-01)
Zhan, Feng-Lin
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Kuo, Li-Min
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Wang, Shi-Wei
;
Lu, Michael S. -C.
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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.
Ultrasensitive and label-free detection of pathogenic avian influenza DNA by using CMOS impedimetric sensors
(2012-05-15)
Lai, Wei-An
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Lin, Chih-Heng
;
Yang, Yuh-Shyong
;
Lu, Michael S. -C.
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生物科技學系
This work work presents miniaturized CMOS (complementary metal oxide semiconductor) sensors for non-faradic impedimetric detection of AIV (avian influenza virus) oligonucleotides. The signal-to-noise ratio is significantly improved by monolithic sensor integration to reduce the effect of parasitic capacitances. The use of sub-mu m interdigitated microelectrodes is also beneficial for promoting the signal coupling efficiency. Capacitance changes associated with surface modification, functionalization, and DNA hybridization were extracted from the measured frequency responses based on an equivalent-circuit model. Hybridization of the AIV H5 capture and target DNA probes produced a capacitance reduction of -13.2 +/- 2.1% for target DNA concentrations from 1 fM to 10 fM, while a capacitance increase was observed when H5 target DNA was replaced with non-complementary H7 target DNA. With the demonstrated superior sensing capabilities, this miniaturized CMOS sensing platform shows great potential for label-free point-of-care biosensing applications. (C) 2012 Elsevier B.V. All rights reserved.
ULTRASENSITIVE DETECTION OF AVIAN INFLUENZA VIRUS BY USING CMOS IMPEDIMETRIC SENSOR ARRAYS
(2012)
Lai, Wei-An
;
Lin, Chih-Heng
;
Yang, Yuh-Shyong
;
Lu, Michael S. -C.
;
生物科技學系
This work presents miniaturized CMOS (complementary metal oxide semiconductor) impedimetric sensors for detection of avian influenza virus (AIV) in the femto-molar level. The sensing resolution is significantly enhanced owing to monolithic sensor integration to reduce the parasitic effect and the use of sub-mu m interdigitated microelectrodes to promote signal coupling efficiency. The 4x4 sensor array contains four electrode designs of different sizes. Capacitance changes associated with surface modification, functionalization, and DNA hybridization were extracted from measured frequency responses based on an equivalent circuit. Hybridization of AIV H5 capture and target DNA produced a percentage capacitance change of -12.8+/-3% among the four designs for target DNA concentrations from 1 fM to 10 fM, while capacitance increases were observed for non-specific binding of the H5 and H7 DNA probes.