Copper doping boosts the catalase-like activity of atomically precise gold nanoclusters for cascade reactions combined with urate oxidase in the ZIF-8 matrix

Abstract

The integration of natural enzymes and nanomaterials with tailorable enzyme-like activities is highly desirable for cascade reactions. However, the ambiguous structure–performance relationship and uncontrollable activity are obstacles to their further application. Herein, we modulated the catalase (CAT)-like activity of atomically precise Au₂₅(MPA)₁₈ (MPA = 3-mercaptopropionic acid) nanoclusters (AuNCs) using single-heteroatom doping. Au₂₄Cu₁(MPA)₁₈ (Au₂₄Cu₁) exhibited elevated CAT-like activity. We revealed that the Cu atom is more favorable than Au in the NCs for stabilizing hydroxyl radicals during the catalytic process. Moreover, the synergetic effects of uric acid (UA) oxidation catalyzed by urate oxidase (UOx), oxygen generation from the toxic intermediate hydrogen peroxide facilitated by Au₂₄Cu₁, and the protective function and nanoconfinement effect of zeolitic imidazolate framework-8 (ZIF-8) enabled the UOx-Au₂₄Cu₁@ZIF-8 composite to degrade more UA. This study provides essential guidance for creating a tailored and biocompatible cascade system.