Construction of biomimetic nanozyme with high laccase- and catecholase-like activity for oxidation and detection of phenolic compounds

Despite the rapid development of nanozyme, it is still challenging to develop multifunctional nanozyme with high oxidase-like activity. In this work, a novel type of amorphous imidazole-Cu nanozyme (I-Cu) with high laccase- and catecholase-like activity was prepared by the water induced precipitation of Cu2+ and imidazole to mimick the N-Cu coordinated environment in their active site. I-Cu shows similar Km but 3.7-fold higher Vmax than laccase at the same mass concentration. The possible catalytic mechanism of I-Cu nanozyme, which is composed of substrate binding, substrate oxidation, oxygen binding and oxygen reduction, is proposed. In addition, it also displays high stability under various pH, temperature, long-term storage and high salinity. The oxidation efficiency of I-Cu nanozyme for environmental phenolic pollutants (2,4-dichlorophenol) is 91.8% at 10 h, which is higher than that of laccase (68.8% at 10 h). Furthermore, the colorimetric and smart phone detection of dopamine by I-Cu nanozyme is developed with the detection limit of 0.412 μM. Therefore, we expect this amorphous nanozyme is promising in the various application of bioremediation and biosensor.