Electrochemical DNA sensor based on methylene blue functionalized polythiophene as a hybridization indicator

► A cationic polymer, methylene blue (MB) functionalized polythiophene, was prepared. ► It was used as an electrochemical indicator for oligonucleotides hybridization detection. ► Compared to MB, This polymer shows much better resistance to the change of ionic strength. ► The dominated interaction of PMT-MB with ODN was investigated by UV-vis spectroscopy.