Detection of PCR Amplification with Electrochemical DNA Biosensor

A novel assay for the cyclic voltammetry (CV) detection of PCR amplification to using electrochemical DNA biosensor was reported. The coupling of DNA electrochemical sensors have specialities of quick detection and cheapness and have the potential of the quantitative evaluation of the PCR amplification. The electrochemical sensor was obtained by immobilizing single-stranded oligonucleotides onto gold electrodes through mercaptan of the DNA bases using N-hydroxysulfosuccinimide (NHS) and N-(3-dimethylamion)propyl-N´-ethyl carbodiimidehydrochloride (EDC) as activation. The hybridization reaction that occurred on the electrode surface was evidenced by cyclic voltammetry (CV) analysis-using as [Co(phen)₃](ClO₄)₃ indicator. The covalently immobilized single- stranded DNA could selectively hybridize with its complementary DNA in solution to form double-stranded DNA on the gold surface. A significant increase of the peak current of cyclic voltammetry (CV) upon the hybridization of immobilized ssDNA with PCR amplification products in the solution was observed. This peak current change was used to monitor the amount of PCR amplification products. Factors such as DNA target concentration and hybridization conditions determining the sensitivity of the electrochemical assay were investigated.