Selenium doped carbonized polypyrrole with high peroxidase-like activity for determining D-penicillamine

Via one-step pyrolysis of polypyrrole and Se powder mixture at a low temperature (450 °C), we reported the fabrication of Se doped carbonized polypyrrole (Se-CP) as nanozyme for determining D-penicillamine (D-PA). After in situ selenium doping, more defect sites and large specific surface area were endowed to Se-CP. Selenium doping in carbon skeleton generated unique C-Se-C bonds, which were conducive to enhancing the asymmetric spin and charge density around the carbon atom, resulting in the acceleration of electron transfer and high catalytic activity. The Se-CP exhibited the capacity to rapidly catalyze the oxidation of TMB by H2O2, and its peroxidase-like activity has increased by 6.51-fold compared to carbonized polypyrrole (CP). The Se-CP exhibited high affinity for substrates TMB and H2O2 with the Km values of 0.0820 mM and 0.182 mM, respectively. Based on the inhibition of D-PA on the high catalytic activity of Se-CP, a sensitive and convenient colorimetric sensing platform has been established for its detection with a detection limit of 60.0 nM. This method was successfully applied to detect the content of penicillamine in actual pharmaceuticals. This work provides a simple and mild strategy to prepare high performance nanozyme for detecting targets of interest.