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Ultramicroscopy. 2008 Sep;108(10):1328-33. doi: 10.1016/j.ultramic.2008.04.045. Epub 2008 May 10.

Label-free target DNA recognition using oligonucleotide-functionalized polypyrrole nanotubes.

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Hyperstructured Organic Materials Research Center and School of Chemical and Biological Engineering, Seoul National University, San 56-1 Shinlimdong, Gwanakgu, Seoul 151-742, Republic of Korea.


Conjugated polymers for oligonucleotide immobilization offer extraordinary potential as transducers for detecting DNA duplex formation, because the electrical, optical, and electrochemical properties are strongly affected by relatively small perturbations. Moreover, carboxylated conducting polymer supports are an attractive alternative due to their versatile immobilization with DNA, protein, and enzyme using various pendant groups: -SH, -NH(2), and -COOH. Therefore, we report the fabrication of carboxylic acid-functionalized polypyrrole nanotubes (CPPy NTs) using oxidant-impregnated template synthesis. The diverse number of carboxylates on the surface of CPPy NTs was applied to binding sites for amino-terminal oligonucleotides. Conductance of single DNA strands (ssDNA) and hybridized DNA helix were readily measured by means of depositing DNA-functionalized nanotubes on gold leads, and indicated high sensitivity (DeltaR/R(0)=1.7) even at low concentration (1 nmol) of target DNA. In addition, target DNA concentration was distinguished up to a narrow difference of 2 nmol. The successful DNA immobilization on polymer nanotubes was confirmed and visualized by the photoluminescence of fluorescein isothiocyanate (FITC)-tagged target DNA using confocal laser scanning microscopy.

[Indexed for MEDLINE]

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