Magnetic MOF-Based Immunosensing Strategy with Quantum Dot Labeling for Efficient Electro-chemiluminescent Detection of Alpha-fetoprotein

This study presents the development of a highly sensitive and selective electrochemiluminescence (ECL) sandwich-type immunosensor for the detection of alpha-fetoprotein (AFP), a critical biomarker for early-stage liver cancer diagnosis. The sensor platform integrates a Fe-Ni-based metal-organic framework (MOF) with magnetic Fe₃O₄ nanoparticles (Fe-Ni-MOF), functionalized with primary antibodies (Ab₁). Carbon quantum dots (CQDs) were conjugated with secondary antibodies (Ab₂) to serve as ECL luminophores. The immunosensor demonstrated a wide linear detection range for AFP from 0.001 to 1000 ng/mL, with a low detection limit of 0.0084 ng/mL. Structural, morphological, thermal, and optical characterizations confirmed the successful synthesis and functionalization of the composite materials. Moreover, the fabricated sensor exhibited excellent reproducibility, specificity, and stability, indicating its potential as a practical tool for early cancer diagnostics in complex biological samples.