Fabrication of DNA, o-phenylenediamine, and gold nanoparticle bioimprinted polymer electrochemical sensor for the determination of dopamine

A simple methodology was used to develop a novel molecularly bioimprinted polymer (MBIP) sensor for the determination of dopamine. The bioimprinted film was prepared by electrochemical entrapment of ds-DNA and Au nanoparticles in the o-phenylenediamine network via one-step electropolymerization on the surface of the modified pencil graphite electrode. The integration of ds-DNA with molecularly imprinted polymer sensors allowed the preparation of novel analytical tools with more selectivity for the determination of dopamine in complex matrices. The fabrication process of the proposed MBIP sensor was evaluated by atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The proposed sensor showed good selectivity for dopamine, compared to the conventional electrochemical methods and the chemicals with high similarity to dopamine. Also, it had a comparable sensitivity, stability, repeatability and reproducibility. Differential pulse voltammetry was applied as a sensitive analytical method for the determination of dopamine and a good linear relationship between dopamine concentration and peak current was obtained within the range of 20-7000 nM with a detection limit of 6 nM. Furthermore, it was successfully applied for determination of dopamine in biological samples.