Electrochemical DNA impedance biosensor for the detection of DNA hybridization with polymeric film, single walled carbon nanotubes modified glassy carbon electrode

作者：Maotang Wang, Wen Jun Gong, Qingmin Meng, Y. Zhang · 发表于：Russian Journal of Electrochemistry · 年份：2011 · DOI：10.1134/s1023193511120123 · 被引用次数：10 · 研究领域：Advanced biosensing and bioanalysis techniques、Electrochemical Analysis and Applications、Electrochemical sensors and biosensors

In this work, we report the fabrication of a sensitive electrochemical DNA impedance biosensor for the detection of sequence-specific target DNA. p-Aminobenzoic acid was first immobilized on the surface of the electrode modified with single walled carbon nanotubes with carboxylic acid groups (SWCNTs) by cyclic voltammetry (CV). A single-stranded DNA probe with a NH2 group at the end (H2N-ssDNA) was then covalently immobilized on the surface of polymeric film at room temperature. The impedance measurement was performed in a solution containing 5 mM K3[Fe(CN)6]/K4[Fe(CN)6]. The change of interfacial charge transfer resistance (R CT) was confirmed the hybrid formation. The difference of R CT was linear with the logarithm of complementary oligonucleotides concentrations in the range of 1.0 × 10−12 to 1.0 × 10−7 M, with a detection limit of 3.5 × 10−13 M (S/N = 3).