Browsing by Author "Tsai, Ming-Shih"

Now showing 1 - 4 of 4

DNA Mismatch Detection by Metal Ion Enhanced Impedance Analysis
(2009-10-01)
Jangjian, Peng-Chung
;
Liu, Tzeng-Feng
;
Tsai, Chuan-Mei
;
Li, Mei-Yi
;
Tsai, Ming-Shih
Conventional diagnoses of genetic mutation and disease depend on the analysis of DNA sequences. However, mismatches in the DNA sequences are difficult to detect using traditional sequencing. Doping metal ions, such as nickel, into the short DNA (28 mer similar to 30 mer), markedly reduces its electrical resistance, which is measured by electrical impedance analysis. The change in resistance that is caused by a mismatched base-pair in short DNA can also be monitored by this approach. In this study, the resistance increased exponentially with the number of mismatched base-pairs. Accordingly, an intuitive and direct method for evaluating the number of DNA mismatches can possibly be developed.
Ni(2+) doping DNA: a semiconducting biopolymer
(2008-09-03)
Jian, Peng-Chung Jang
;
Liu, Tzeng-Feng
;
Tsai, Chuan-Mei
;
Tsai, Ming-Shih
;
Chang, Chia-Ching
DNA is a one-dimensional nanowire in nature, and it may not be used in nanodevices due to its low conductivity. In order to improve the conducting property of DNA, divalent Ni(2+) are incorporated into the base pairs of DNA at pH >= 8.5 and nickel DNA (Ni-DNA) is formed. Conducting scanning probe microscopy (SPM) analysis reveals that the Ni-DNA is a semiconducting biopolymer and the Schottky barrier of Ni-DNA reduces to 2 eV. Meanwhile, electrochemical analysis by cyclic voltammetry and AC impedance shows that the conductance of Ni-DNA is better than that of native DNA by a factor of approximately 20-fold. UV spectroscopy and DNA base pair mismatch analyses show that the conducting mechanism of Ni-DNA is due to electrons hopping through the pi-pi stacking of DNA base pairs. This biomaterial is a designable one-dimensional semiconducting polymer for usage in nanodevices.
Ni2+ doping DNA: a semiconducting biopolymer
(2008-09-03)
Jian, Peng-Chung Jang
;
Liu, Tzeng-Feng
;
Tsai, Chuan-Mei
;
Tsai, Ming-Shih
;
Chang, Chia-Ching
DNA is a one-dimensional nanowire in nature, and it may not be used in nanodevices due to its low conductivity. In order to improve the conducting property of DNA, divalent Ni2+ are incorporated into the base pairs of DNA at pH >= 8.5 and nickel DNA (Ni-DNA) is formed. Conducting scanning probe microscopy (SPM) analysis reveals that the Ni-DNA is a semiconducting biopolymer and the Schottky barrier of Ni-DNA reduces to 2 eV. Meanwhile, electrochemical analysis by cyclic voltammetry and AC impedance shows that the conductance of Ni-DNA is better than that of native DNA by a factor of approximately 20-fold. UV spectroscopy and DNA base pair mismatch analyses show that the conducting mechanism of Ni-DNA is due to electrons hopping through the pi-pi stacking of DNA base pairs. This biomaterial is a designable one-dimensional semiconducting polymer for usage in nanodevices.
Room temperature negative differential resistance in DNA-based molecular devices
(2009-01-26)
Jangjian, Peng-Chung
;
Liu, Tzeng-Feng
;
Li, Mei-Yi
;
Tsai, Ming-Shih
;
Chang, Chia-Ching
A molecular device fabricated from metallic deoxyribonucleic acid (M-DNA) exhibits a negative differential resistance (NDR) behavior. When two gold electrodes were connected by Ni(2+)-chelated DNA, which was converted from lambda-DNA, not only was the conductivity of DNA improved, but a NDR device was formed as a full cyclic voltage sweep was applied to measure its current versus voltage characteristics at room temperature and in an ambient environment. Such electronic characteristics of a M-DNA device may have been caused by the redox reactions of Ni ions. This finding provides a simple way to construct electrical nanodevices from biological molecules.