Amperometric urea biosensor based on immobilized urease on polypyrrole and macroporous polypyrrole modified Pt electrode

Abstract

Biosensing of urea by a biosensor as a direct detection method at ambient temperature and pressureinstead of chromatography leads to a significant reduction in processing costs. Amperometric biosensors based onurease immobilization on macroporous polypyrrole (MPPy) and pyrrole on the surface of a Pt electrode were developed.Applying cyclic voltammetry (CV), we demonstrated the synthesis of MPPy using monodispersed polystyrene spheres(460 nm) as a template. CV and chronoamperometric studies were conducted to evaluate the electrochemical currentof the modified electrodes. For the electrode with polypyrrole (PPy), the biosensor response was linear in the range of1.67–8.32 mM (R2 = 0.99). Sensitivity, detection limit, and response time of this biosensor were 0.0035 mA mM −1,2.57 mM, and ∼7 s, respectively. For the electrode with MPPy, the linear range was 0.5–10.82 mM (R2 = 0.99). Forthis biosensor, sensitivity, detection limit (S/N = 3), and response time were 0.0432 mA mM −1, 0.208 mM, and ∼5 s,respectively. The modified biosensor with MPPy showed high stability and desirable selectivity for urea.