‘Three Birds With One Stone’ functionalized metal–organic frameworks for facile and efficient chemiluminescent immunoassays

The luminol–H2O2 system is crucial in the field of chemiluminescence (CL) analysis. However, luminol exhibits improved solubility and luminescence only in an alkaline environment, and its preparation process is cumbersome. This inconvenience highlights the need for developing a simple and universally applicable method in this regard. This study integrates luminol and a catalyst into metal–organic frameworks (MOFs) for fabrication of functionalised MOF nanoparticles. Further, PEGylated hematin (PEG = polyethylene glycol) was prepared. This modification with PEG enhanced the catalytic properties of hematin and facilitated the formation of zeolitic imidazole framework-8 nanoparticles. Furthermore, the built-in catalyst enhanced the CL in terms of strength and persistence. These MOF nanoparticles were used as signal markers to fabricate a sandwich-type CL immunosensor for detection of carcinoembryonic antigen, which is a disease marker, following which highly satisfactory analytical test results are obtained. This approach of integrating luminophores and catalysts offers a new idea for generating novel materials in the CL analysis field.