Cu/Ce multivalent metal-organic frameworks: polydopamine-electronic modulation for multi-enzyme activity and dual-mode multi-target detection

Conducting multi-mode detection of multiple targets simultaneously on a single platform can significantly enhance the accuracy and flexibility of the detection process. Herein, a fluorescence-colorimetric dual-mode sensing platform was constructed by in-situ coating polydopamine (PDA) on Cu/Ce multivalent metal-organic frameworks (Cu/Ce-MOFs). The obtained Cu/Ce-MOFs@PDA exhibits excellent fluorescent properties and multienzyme-like nanozymes activity (including mimics oxidase, peroxidase, phosphatase, and laccase), facilitating dual-mode detection of pesticides, phenolic pollutants, and biomolecules. Particularly, the excellent detection performance is attributed to the synergistic Ce 4+ /Ce 3+ -Cu 2+ /Cu + redox cycling and the interfacial electron modulation of polydopamine. In addition, the sensing platform demonstrates excellent signal reproducibility, remarkable anti-interference capabilities and strong applicability to real samples, with a recovery ranging from 84.3% to 118.8%. This work demonstrates a generalizable approach for constructing multifunctional bimetallic MOFs-based nanozymes, enabling the development of integrated analytical platforms with multi-mode signal outputs for environmental and biosensing applications.