Browsing by Author "Chen, Chen Chia"

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A novel nanofabrication technique for the array of nanogap electrodes
(2006-06-01)
Chen, Chen Chia
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Sheu, Jeng Tzong
;
Chiang, Sung Lin
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Sheu, Meng Lieh
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材料科學與工程學系奈米科技碩博班
We demonstrated a sidewall spacer nanofabrication technique for nanogap, electrodes fabrication. Nanogap between gold and polycrystalline silicon (ploy-Si) electrodes is defined without using any advanced lithographic techniques. The feature size of nanogap electrodes fabricated using this technique is mainly determined by the thickness of sidewall spacer. The proposed technique showed that reproducible nanogap distances from 10 to 100 nm on the 6 in. wafer were easily obtained. Binding of 15 nm gold nanoparticles across the 10 nm electrodes leading to a drastic change of the electrical conductance has also been demonstrated. Under a bias of 3 V, the conductive current increases from 2 pA to 300 nA after binding of 15 nm gold nanoparticles across the 10-nm electrodes. We believed that this technique can be contributed to the development of high-density nanogap electrodes for applications in biomolecules or nanoparticles detection.
Detection of an uncharged steroid with a silicon nanowire field-effect transistor
(2009-04-24)
Chang, Ko Shing
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Chen, Chen Chia
;
Sheu, Jeng Tzong
;
Li, Yaw-Kuan
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材料科學與工程學系奈米科技碩博班
Among biosensors of various types, the silicon nanowire field-effect transistor (SiNW-FET) is believed to be the most sensitive and powerful device for bio-applications. The principle of sensing is based on the variation of conductivity resulting from a disturbance of charge on the surface of the SiNW-FET, but this detection is feasible predominantly for charged analytes, such as a protein, DNA, antibody, virus etc. The objective of our work was to overcome this intrinsic weakness of a SiNW-FET and to develop a platform to detect steroids. For this purpose, we designed an engineered protein. Delta(5)-3-ketosteroid isomerase, to function as a steroid acceptor that was chemically modified with a carbon chain-linked 1,5-EDANS moiety, and further immobilized on the surface of a silicon nanowire. In the presence of a steroid, the negatively charged 1,5-EDANS moiety, which presumably occupies the steroid-binding site, is expelled and exposes to the nanowire surface. The electrical response produced from the 1,5-EDANS moiety is measured and the concentration is calculated accordingly. The sensitivity of this novel nano-bio-device can attain a femtomolar level. (C) 2009 Elsevier B.V. All rights reserved.