Chemiluminescent Two-Dimensional Metal-Organic Framework with Multiple Metal Catalytic Centers and Its Peroxidase-like Activity for Sensing of Small Molecules.

Two-dimensional (2D) porphyrin-based metal-organic frameworks (MOFs) hold great promise in a variety of areas with the merits of large lateral size and abundant functional groups. The chemiluminescent 2D MOF has rarely been reported. In this work, a chemiluminescence (CL) reagent and noble metal nanoparticle dual-functionalized 2D MOF (ABEI/AuNPs/CuTCPP) was developed through the surfactant-assisted and in situ synthetic growth method, exhibiting strong and stable CL property and outstanding peroxidase-mimicking activity. The special nanostructure of ABEI/AuNPs/CuTCPP endowed it with multi-catalytic routes in the CL reaction, which showed a unique pH-regulated and time-resolved CL kinetic curve. A CL mechanism with multi-catalytic centers has been proposed. AuNPs participated in the fast catalytic process and CuTCPP in the slow and strong catalytic reaction. Owing to the impressive structural features and intrinsic enzymatic tandem reaction from natural enzyme to artificial enzyme, a model biosensor was designed for the detection of small metabolic molecules. Employing choline as a model target, the proposed biosensor showed a highly sensitive response to choline in the linear range from 0.3 to 300 μM with a detection limit of 82.6 nM. Significantly, the strategy may be generalized to the monitoring of other biologically important compounds involved in the production of H2O2.