Single stranded DNA-guided electropolymerization of polythionine nanostrip to the sensing of H2O2

The electropolymerization of thionine with the guidance of DNA molecular template was described in this paper. The prepared polythionine (PTH) dispersed uniformly on the electrode surface and presented a novel flexual nanostrip morphology with the average diameter of 90 nm and length of 500 nm. However, PTH fabricated without DNA-guided electropolymerization presented a clustered granular morphology. The electrochemical redox behavior of PTH via DNA-guided electropolymerization was considerably enhanced compared to that of PTH without DNA molecular template. The significant improvement of the redox property might be attributed to the in situ PTH chains growth along DNA strands. In neutral environment, the PTH/DNA on the carbon paste electrode showed a pair of well-defined redox peaks and excellent electrocatalytic activity toward the reduction of H2O2. Under optimal conditions, H2O2 was amperometrically determined by using the as-prepared PTH/DNA nanostrips in the concentration range of 0.99–8.26 mM.