Echinomycin and cobalt-phenanthroline as redox indicators of DNA hybridization at gold electrodes.

A bis-intercalator echinomycin (ECHI) and a simple intercalator [Co(phen)3]3+ were used as a novel electrochemical redox indicators to detect DNA hybridization at gold electrodes (AuE). In order to minimize the nonspecific adsorption of oligonucleotides (ODN), the thiol-derivatized oligonucleotides were immobilized onto AuE in the first step, and the exposition of AuE to 6-mercapto-1-hexanol (MCH) followed in the second step of this procedure. In this arrangement good reproducibility and discrimination between single-stranded (ss) probe and double-stranded (ds) hybrid DNA were obtained.

Disposable electrochemical biosensor for the detection of the interaction between DNA and lycorine based on guanine and adenine signals.

The interaction of lycorine (LYC) with calf thymus double stranded DNA (dsDNA) and calf thymus single stranded DNA (ssDNA) was studied electrochemically based on the oxidation signals of guanine and adenine by using differential pulse voltammetry (DPV) at carbon paste electrode (CPE) and pencil graphite electrode (PGE). As a result of the interaction of LYC with DNA, the voltammetric signal of guanine and adenine greatly decreased. The changes in the experimental parameters such as the concentration of LYC, and the accumulation time of LYC were studied by using DPV with PGE.