Bioinspired coassembly of peptide, imidazolecarboxaldehyde, and copper for nanozyme with laccase-like activity for colorimetric detection of epinephrine

Epinephrine plays a vital role in the central nervous system, but its abnormal levels will result in various diseases. Therefore, facile, rapid and accurate detection of epinephrine is essential for clinical application. Due to its phenolic structure, epinephrine can be detected through colorimetric assays as it is oxidized by laccase to form a colored quinone compound. In this work, a laccase-like nanozyme, diphenylalanine peptide/4imidazolecarboxaldehyde-Cu (FF/ICA-Cu), was designed to mimic the active center of natural laccase. The as- synthesized FF/ICA-Cu nanozyme showed high laccase-like activity because of its structural similarity to the natural laccase active center. Moreover, it exhibited excellent stability and recyclability, even under harsh conditions. Based on its laccase-like activity, a sensitive and selective sensing strategy for epinephrine was developed. This approach offers a promising avenue for accurately detecting epinephrine and designing catalysts with potential for future industrial applications.