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ABSTRACT: A novel electrochemical DNA biosensor for single-nucleotide polymorphism (SNP) analysis was developed. In this work, an oligonucleotide-incorporated nonfouling surface (ONS) was constructed to resist nonspecific absorption. The biosensor was developed using a 16-electrode array for high-throughput SNP analysis. The proposed strategy was primarily based on specific oligonucleotide ligation. Fully matched target DNA templated the ligation between a capture probe assembled on gold electrodes and a tandem signal probe with a biotin moiety that could capture avidin-horseradish peroxidase and sequentially generate a catalysed amperometric signal. A pre-core mutation in the hepatitis B virus (HBV) genome at G1896A and two adjacent polymorphisms in the human CYP2C19 genome at C680T and G681A were analysed. Polymerase chain reaction (PCR) products were used as real-life samples and analysed. Our results showed that 10% of a single-mismatched mutant gene was clearly distinguished with a current signal 16 times higher than that of the blank sample, demonstrating the selectivity and practicability of the multiplexed electrochemical DNA biosensor.
Biosensors & bioelectronics 11/2012; 42C:516-521. · 5.43 Impact Factor
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ABSTRACT: We report here a practical application of a multiplexed electrochemical DNA sensor for highly specific single-nucleotide polymorphism (SNP) detection. In this work, a 16-electrode array was applied with an oligonucleotide-incorporated nonfouling surfaces (ONS) on each electrode for the resistance of unspecific absorption. The fully matched target DNA templated the ligation between the capture probe assembled on gold electrodes and the tandem signal probe with a biotin moiety, which could be transduced to peroxidase-based catalyzed amperometric signals. A mutant site (T93G) in uidA gene of E. coli was analyzed in PCR amplicons. 10% percentage of single mismatched mutant gene was detected, which clearly proved the selectivity of the multiplexed electrochemical DNA biosensor when practically applied.
Sensors 01/2011; 11(8):8018-27. · 1.74 Impact Factor
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ABSTRACT: In this work, we report a multiplexed electrochemical DNA sensor for highly specific single-nucleotide polymorphism (SNP) detection by using oligonucleotide-incorporated nonfouling surfaces (ONS). A typical "sandwich" scheme was employed to perform the SNP assay. The presence of the target DNA templated the ligation between the capture probe DNA anchored on gold electrodes and the tandem reporter probe tagged with a biotin moiety, which could be transduced to peroxidase-based catalyzed amperometric signals. This method could effectively differentiate SNP sites with only one-base mismatch. Importantly, the differentiation ratio was significantly higher than that with surfaces without the nonfouling property, which clearly demonstrated the superiority of the ONS strategy.
The Journal of Physical Chemistry B 04/2010; 114(19):6703-6. · 3.70 Impact Factor
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ABSTRACT: In this work, we report a novel electrochemical DNA sensor based on a nonfouling monolayer structure self-assembled at gold surfaces. Self-assembled monolayers (SAMs) with oligo(ethylene glycol) (OEG)-terminated thiols are known to be highly protein-resistant and effectively repel nonspecific adsorption. We found that a mixed SAM structure incorporating thiolated oligonucleotides and OEG thiols (SH-DNA/OEG) exhibited the similar non-fouling feature. More importantly, it allowed facile electron transfer across the monolayer and thus was fully compatible with electrochemical detection. On the basis of this SH-DNA/OEG platform, we developed a sandwich-type electrochemical sensor for the sequence-specific detection of DNA targets. This sensor was able to detect as little as 1 pM target DNA even in the presence of complicated biological fluids such as human serum. We also employed this sensor to directly detect a polymerase chain reaction (PCR) amplicon from the genomic DNA of Escherichia coli K12, which led to a very low detect limit of 60 fg (approximately 10 copies).
Analytical Chemistry 01/2009; 80(23):9029-33. · 5.86 Impact Factor
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ABSTRACT: In this report, we systematically investigated DNA immobilization at gold surfaces with electrochemical techniques. Comparative cyclic voltammetric and chronocoulometric studies suggested that DNA monolayers immobilized at gold surfaces were not homogeneous. Nonspecific Au-DNA interactions existed even with the treatment of mercaptohexanol, which was known to competitively remove loosely bound DNA at gold surfaces. While both thiolated and nonthiolated DNA formed monolayers on gold surfaces, their hybridization abilities were distinctly different. In contrast to thiolated DNA probes, nonthiolated DNA probes immobilized at gold surfaces were essentially nonhybridizable. The experimental results presented here might be useful for the design of high-performance electrochemical DNA sensors.
Analytical Chemistry 11/2005; 77(19):6475-80. · 5.86 Impact Factor
