Electrochemical detection of DNA hybridization using methylene blue as an electrochemical hybridization indicator

【Objective】To prepare an electrochemical DNA biosensor based on methylene blue(MB) as redox indicator for DNA hybridization detection.【Methods】 Oligonucleotide probes with-SH at the 5′end were attached onto the Au surface.Hybridization was induced by exposure of Au electrode to complementary ssDNA in solution.The ssDNA was detected by linear sweep voltammetry whether it was assembled on the electrode surface completely.Then probe DNA and target DNA that complement with probe DNA were used for assemble. 【Results】 The increases could be observed in the peak currents of dsDNA after hybridizated with complement ssDNA.The peak current of MB after hybridization with the target DNA was linearly related to the value of the target DNA concentration ranging from 5.0×10-10 to 1.8×10-9mol/L.A detection limit of 5.0×10-10mol/L of oligonucleotides could be estimated.【Conclusion】The result suggests that this hybridization biosensor using MB as indicator of hybridization reaction can be conveniently used to monitor DNA hybridization with a high sensitivity.