A highly soluble poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid)/Au nanocomposite for horseradish peroxidase immobilization and biosensing

A highly soluble poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid)/Au (PEDOT-PSS/Au) nanocomposite was prepared via one-step chemical synthesis and the matrix was characterized by UV–vis spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscope (TEM). Due to the excellent aqueous compatibility and biocompatibility, the PEDOT/PSS-Au nanocomposite can be used as biomaterial for enzymes immobilization. In this system, redox enzyme, horseradish peroxidase (HRP) was integrated with PEDOT/PSS-Au nanocomposite and the direct electron transfer of HRP was observed. Moreover, we find that the HRP/PEDOT-PSS/Au modified electrode shows excellent electrocatalytic ability for H2O2 and the formal Michaelis–Menten constant ( K m app ) was 0.78 mmol/L. The response currents have good linear relation with the concentrations of H2O2 with a linear range from 2.0 × 10−7 to 3.8 × 10−4 mol/L.