Highly sensitive chemiluminescence immunoassay utilizing functionalized magnetic metal-organic framework materials for the detection of CEA and CA199

Background: In response to the urgent need for highly sensitive and rapid combined detection of multiple tumor markers for the early diagnosis of colorectal cancer, this work innovatively constructs a magnetically-driven chemiluminescence (CL) immunosensing platform (CoFe₂O₄@ZIF-8/luminol-Au NPs). Results: CoFe₂O₄ NPs were firstly aminated via solvothermal method and lysine modification to provide specific binding sites. ZIF-8 was then grown in situ to form a core-shell structure with high specific surface area for efficient luminol loading. Finally, Au NPs were generated in situ within ZIF-8, simultaneously immobilizing luminol to form composite signal units. This design integrates magnetic separation, confinement effects, and signal amplification, generating an ideal microenvironment for enhanced CL reactions. The label-free CL immunoassay achieves an impressive limit of detection (LOD) of 22 fg/mL for CEA and 5.4 fg/mL for CA199, with broad linear ranges spanning over 5 orders of magnitude. The entire detection process is completed within 30 min, and the analysis of real serum samples demonstrates good recoveries.