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Updated: May 25, 2026
Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Triplex signal amplification for electrochemical DNA biosensing by coupling probe-gold nanoparticles-graphene
Haifeng Dong1, Zhu Zhu, Huangxian Ju
1State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
Abstract:
An ultrasensitive electrochemical DNA biosensor was constructed by assembling probe labeled gold nanoparticles (ssDNA-AuNP) on electrochemically reduced graphene oxide (ERGO) modified electrode with thiol group tagged (GT) DNA strand (d(GT)(29)SH) and coupling with horseradish peroxidase (HRP) functionalized carbon sphere (CNS) as tracer. The heteronanostructure formed on the biosensor surface appeared relatively good conductor for accelerating the electron transfer, while the HRP tagged CNS provided dual signal amplification for electrochemical biosensing. The triplex signal amplification strategy produced an ultrasensitive electrochemical detection of DNA down to attomolar level (5 aM) with a linear range of 5 orders of magnitude (from 1 × 10(-17)M to 1 × 10(-13)M), and appeared high selectivity to differentiate single-base mismatched and three-base mismatched sequences of DNA. The proposed approach provided a simple and reliable method for DNA detection with high sensitivity and specificity, indicating promising application in bioanalysis and biomedicine.
