Hollow, Spherical, Poly(3,4-ethylenedioxythiophene)-Bearing Methanethiol as a Gold Stabilizer for High-Efficiency Electrochemical Sensors

Conducting polymers decorated with noble metals are good electrochemical sensors for biological species. In this work, we developed a polymer of methanethiol-grafted poly(3,4-ethylenedioxythiophene) hollow spheres (Poly(EDOT-MeSH)) using SiO2 nanospheres as a hard template. The Poly(EDOT-MeSH) spheres were used as both a reductant and stabilizer to decorate gold nanoparticles (Au NPs). FTIR, XRD, EDX, SEM and TEM analyses were used to characterize the Poly(EDOT-MeSH)/Au hollow spheres. The chemical bond between S and Au was confirmed by XPS. The electrochemical performance of the Poly(EDOT-MeSH)/Au hollow spheres was determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results revealed that the Poly(EDOT-MeSH)/Au hollow sphere-based electrochemical sensor possesses an excellent conductivity and high redox reversibility with detection limits (S/N = 3) of 5.3, 0.04 and 0.12 μM in the linear ranges of 50–320 μM, 0.05 μM − 780 μM and 0.8 μM − 250 μM for the determination of AA, DA and UA, respectively. These results will further the development of this type of electrochemical sensor for biological species.