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 mu M. Therefore, we expect this amorphous nanozyme is promising in the various application of bioremediation and biosensor.

Automated summary

In this study, a novel type of amorphous imidazole-Cu nanozyme with high laccase- and catecholase-like activity was prepared. The nanozyme exhibited higher catalytic activity and stability compared to laccase, and showed potential applications in environmental pollution remediation and dopamine detection.