Preparation of electroconductive film based on self-assembled aminothiophene/poly(γ-glutamate) nanoparticles and its application in biosensor

Abstract

An electroconductive nanoparticles (NPs) film consisting of sodium poly(γ-glutamate) (γ-PGANa) and 3,4-diaminothiophene dihydrochloride (DATh) was simply prepared through macromolecular self-assembly and electropolymerization methods. Firstly, the γ-PGANa and the DATh underwent a complexation to form DATh/γ-PGANa composites through the electrostatic interaction; the DATh/γ-PGANa composites were then self-assembled into DATh/γ-PGANa NPs through decreasing the pH value in aqueous solution. Next, an electroconductive NPs film was formed on the surface of a gold electrode by casting the DATh/γ-PGANa NPs and subsequently electropolymerizing the DATh. Last, horseradish peroxidase and Nafion were cast onto the NPs film to obtain an enzymatic biosensor for H2O2 detection. The electroconductive DATh/γ-PGANa NPs film endowed the biosensor with high sensitivity. Under the optimal conditions, the prepared biosensor showed a linear range from 1 × 10−11 to 1 × 10−4 mol·L−1 with a detection limit of 3 × 10−12 mol·L−1 for H2O2 detection. The biosensor can retain its detection performance for 4 weeks. The response currents of the biosensor changed little after adding the interferent into the analyte. The standard deviation of the response between different biosensors did not exceed 2.5%.