Electrical detection of deoxyribonucleic acid hybridization based on carbon-nanotubes/nano zirconium dioxide/chitosan-modified electrodes

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This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
A novel and sensitive electrochemical DNA biosensor based on nanoparticles ZrO”2 and multi-walled carbon nanotubes (MWNTs) for DNA immobilization and enhanced hybridization detection is described. The MWNTs/nano ZrO”2/chitosan-modified glassy carbon electrode (GCE) was fabricated and oligonucleotides were immobilized to the GCE. The hybridization reaction on the electrode was monitored by differential pulse voltammetry (DPV) analysis using electroactive daunomycin as an indicator. Compared with previous DNA sensors with oligonucleotides directly incorporated on carbon electrodes, this carbon nanotube-based assay with its large surface area and good charge-transport characteristics increased DNA attachment quantity and complementary DNA detection sensitivity. The response signal increases linearly with the increase of the logarithm of the target DNA concentration in the range of 1.49×10^-^1^0 to 9.32×10^-^8molL^-^1 with the detection limit of 7.5×10^-^1^1molL^-^1 (S/N=3). The linear regression equation is I=32.62+3.037logC”D”N”A (molL^-^1) with a correlation coefficient value of 0.9842. This is the first application of carbon nanotubes combined with nano ZrO”2 to the fabrication of an electrochemical DNA biosensor with a favorable performance for the rapid detection of specific hybridization.

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Electrochemical impedance detection of DNA hybridization based on the formation of M-DNA on polypyrrole/carbon nanotube modified electrode

Product Description
This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
A new selective and sensitive biosensing strategy for electrochemical impedance spectroscopy (EIS) measurement of DNA hybridization is described. The detection approach relied on the doping of nucleic acid probes within electropolymerized polypyrrole (PPy) film onto a carboxylic group-functionalized multi-walled carbon nanotubes (MWNTs-COOH) modified electrode and monitoring the impedance changes provoked by the metallation of helix DNA after hybridization. Oligonucleotide probes served as the solo counter anions during the growth of conducting PPy film on the carbon nanotube modified electrode. As a consequence of hybridization and the formation of metallized double-stranded DNA (M-DNA), significant changes in electrochemical impedance values (both in real component Z”r”e and imaginary component Z”i”m) coming from the change of electronic transport resistance of the modified electrode were observed, especially a visible decrease in the Z”r”e. Based on the unique response @DZ”r”e after hybridization and metallation at 5469Hz, only the complementary DNA sequence had an obvious signal of the impedance decrease when compared with 1-base, 3-base mismatched and non-complementary sequences; hybridization amounts of 1-base, 3-base mismatched sequences were obtained only 35.7 and -5.8% responses. The protocol also offered high sensitivity with the detection limitation was 5×10^-^1^1M using 3 S.D., n=11. Results showed that Zn^2^+-DNA had the best ability to transport electrons in M-DNA double-stranded chains when compared with Co^2^+-DNA and Ni^2^+-DNA on the same condition.

BUY FROM AMAZON–>> Electrochemical impedance detection of DNA hybridization based on the formation of M-DNA on polypyrrole/carbon nanotube modified electrode