Preparation Of Electroconductive Film Based On Self-Assembled Aminothiophene/Poly(Gamma-Glutamate) Nanoparticles And Its Application In Biosensor

An electroconductive nanoparticles (NPs) film consisting of sodium poly(gamma-glutamate) (gamma-PGANa) and 3,4-diaminothiophene dihydrochloride (DATh) was simply prepared through macromolecular self-assembly and electropolymerization methods. Firstly, the gamma-PGANa and the DATh underwent a complexation to form DATh/gamma-PGANa composites through the electrostatic interaction; the DATh/gamma-PGANa composites were then self-assembled into DATh/gamma-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/gamma-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/gamma-PGANa NPs film endowed the biosensor with high sensitivity. Under the optimal conditions, the prepared biosensor showed a linear range from 1 x 10(-11) to 1 x 10(-4) mol.L-1 with a detection limit of 3 x 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%.