Electrochemical detection of hybridized DNA using reduction of methylene blue

One of the important roles of a DNA sensor is the capability of detecting genetic diseases or mutations by analyzing DNA sequences. The electrochemical detection method can be simpler and cheaper than other methods available and hence this method was investigated in this paper. For successful electrochemical detection, several aspects should be considered including chemical treatment of the electrode surface, DNA immobilization on an electrode, hybridization, choice of an intercalator to be bound to double stand DNA selectively, and equipment for detecting and analyzing the output signal. The intercalator bound to double strand DNA results in an electrical current. With the electrochemical detection method, double strand DNA was distinguished from single strand DNA or bare gold electrode by measuring the reduction current of intercalator. Also, it was found that the reduction current of the intercalator is proportional to the concentration of target DNA to be hybridized with probe DNA. Therefore, it is possible to realize a simple and cheap DNA sensor using the electrochemical detection method for DNA sequencing.