Simultaneous determination of purine and pyrimidine bases in DNA using poly(3,4-ethylenedioxythiophene)/graphene composite film

• A poly(3,4-ethylenedioxythiophene)/graphene composite film was prepared.
• The modified electrode exhibited good electrocatalytic activity to DNA bases.
• The sensor showed high sensitivity, wide linear range and high stability.

A simple and reliable method for simultaneous determination of purine and pyrimidine (guanine, adenine, thymine and cytosine) was developed at poly(3,4-ethylenedioxythiophene)/electro-deposited graphene modified glassy carbon electrode (PEDOT/GR/GCE). Scanning electron microscopy and electrochemical impedance spectroscopy were used to examine the morphology and interface property of PEDOT/GR film. Differential pulse voltammetry was utilized to investigate the electrochemical behavior of DNA bases in 0.1 M PBS (pH 7.4). The results showed that the peaks of four bases were well separated. The proposed sensor exhibited low detection limit, high sensitivity and wide linear range for simultaneous detection of four DNA bases, with high stability.

Electrocatalytic oxidation of purine and pyrimidine at different electrodes was investigated by differential pulse voltammetry. The peak currents of G, A, T, C increased significantly and the peak potentials shifted negatively at PEDOT/GR/GCE, demonstrating that the combination of the excellent properties of GR and PEDOT enhanced the kinetics of the electrochemical process as an efficient promoter.DPVs of GCE (a), GR/GCE (b), PEDOT/GCE (c), PEDOT/GR/GCE (d) in the presence of 20.0 μM G, 20 μM A, 100 μM T and 100 μM C, and PEDOT/GR/GCE (e) in blank pH 7.4 PBS.Figure optionsDownload as PowerPoint slide