Growth of Polypyrrole–Horseradish Peroxidase Microstructures for $\hbox {H}_{2}\hbox {O}_{2}$ Biosensor

Conducting polymer microstructures for enzymatic biosensors are developed by a facile electrochemical route. Horseradish peroxide (HRP)-entrapped polypyrrole (PPy) films with bowl-shaped microstructures are developed on stainless steel (SS 304) substrates by a single-step process. Potentiodynamic scanning/cyclic voltammetry is used for generation of PPy microstructures using electrogenerated oxygen bubbles stabilized by zwitterionic surfactant/buffer N-2-hydroxyethylpiperazine N-2-ethanesulfonic acid as soft templates. Scanning electron microscopic images reveal the bowl-shaped structures surrounded by cauliflower-like fractal PPy films and globular nanostructures. Raman spectroscopy reveals the oxidized nature of the film. Sensing properties of PPy-HRP films for hydrogen peroxide (H₂O₂) are demonstrated. Electrochemical characterization of the sensor films is done by linear sweep voltammetry (LSV) and amperometry. LSV results indicated the reduction of H₂O₂ and linearity in response of the sensing film. The amperometric biosensor has a performance comparable to those in the literature with advantages of hard-template free synthesis procedure and a satisfactory sensitivity value of 12.8 μA/(cm²·mM) in the range of 1-10 mM H₂O₂.