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Chronocoulometric DNA biosensor based on a glassy carbon electrode modified with gold nanoparticles, poly(dopamine) and carbon nanotubes |
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| Authors: | Xiao Dong Xiaocui Lu Keying Zhang Yuzhong Zhang |
| Institution: | 1. College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo-Biosensing, Anhui Normal University, Wuhu, 241000, People’s Republic of China 2. Department of Chemistry-Biology, Anhui Key Laboratory of Spin Electron and Nanomaterials (Cultivating Base), Suzhou University, Suzhou, Anhui, 234000, People’s Republic of China |
| Abstract: | We describe a sensitive chronocoulometric biosensor for the sequence-specific detection of DNA. It is based on a glassy carbon electrode modified with multi-walled carbon nanotubes, polydopamine, and gold nanoparticles. The ruthenium(III)hexammine complex acts as the electrochemical indicator. Electrochemical impedance spectra and scanning electron microscopy are employed to investigate the assembly of the electrode surface. The signals of the ruthenium complex electrostatically bound to the anionic phospho groups of the DNA strands are measured by chronocoulometry before and after hybridization. The difference in signal intensity is linearly related to the logarithm of the concentration of the target DNA in the range of 1.0 nM to 10 fM with a detection limit of 3.5fM (S/N?=?3) under optimal conditions. This biosensor exhibits excellent sensitivity and selectivity and has been used for an assay of complementary target DNA in human serum sample with satisfactory results. We describe a sensitive chronocoulometric biosensor based on a glassy carbon electrode modified with gold nanoparticles, poly(dopamine), and carbon nanotubes. The biosensor exhibits excellent sensitivity and selectivity and has been used for an assay of Helicobacter pylori in human serum with a satisfactory result. |
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