title: Electrochemical DNA biosensor based on conducting polyaniline nanotube array.
abstract: Most of the recent developments in ultrasensitive detection of nucleic acid are based on the gold nanoparticles and carbon nanotubes as a medium of signal amplification. Here, we present an ultrasensitive electrochemical nucleic acid biosensor using the conducting polyaniline (PANI) nanotube array as the signal enhancement element. The PANI nanotube array of a highly organized structure was fabricated under a well-controlled nanoscale dimension on the graphite electrode using a thin nanoporous layer as a template, and 21-mer oligonucleotide probes were immobilized on these PANI nanotubes. In comparison with gold nanoparticle- or carbon nanotube-based DNA biosensors, our PANI nanotube array-based DNA biosensor could achieve similar sensitivity without catalytic enhancement, purification, or end-opening processing. The electrochemical results showed that the conducting PANI nanotube array had a signal enhancement capability, allowing the DNA biosensor to readily detect the target oligonucleotide at a concentration as low as 1.0 fM (approximately 300 zmol of target molecules). In addition, this biosensor demonstrated good capability of differentiating the perfect matched target oligonucleotide from one-nucleotide mismatched oligonucleotides even at a concentration of 37.59 fM. This detection specificity indicates that this biosensor could be applied to single-nucleotide polymorphism analysis and single-mutation detection.
authors.affiliation: Division of Materials Surface Engineering, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China. hxchang@imr.ac.cn
authors.forename: Haixin
authors.initials: H
authors.lastname: Chang
authors.forename: Ying
authors.initials: Y
authors.lastname: Yuan
authors.forename: Nanlin
authors.initials: N
authors.lastname: Shi
authors.forename: Yifu
authors.initials: Y
authors.lastname: Guan
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D004247:DNA / Q000032:analysis*; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D009154:Mutation / Q000235:genetics; D043942:Nanotubes / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry; D015345:Oligonucleotide Probes; D010316:Particle Size; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D016062:Porosity; D012680:Sensitivity and Specificity
chemical_list: D000814:Aniline Compounds; D037742:Nanotubes, Carbon; D015345:Oligonucleotide Probes; C416807:polyaniline; D006046:Gold; D006108:Graphite; D004247:DNA