A Novel Multiplex Electrochemiluminescent Biosensor Enabled by Magnetic MOFs and Quantum Dots for Early Alzheimer’s Biomarker Detection

Abstract

Early and multiplex detection of Alzheimer’s disease (AD) biomarkers is essential for timely diagnosis and accurate disease staging; however, conventional immunoassays lack the sensitivity and multi-channel capability required to quantify extremely low-abundance proteins in complex biological matrices. In this work, we present a novel triple-target electrochemiluminescence (ECL) biosensor based on magnetic metal–organic frameworks (MMOFs) integrated with quantum-dot (QD)–mediated resonance energy transfer (RET) for the simultaneous detection of three clinically significant AD biomarkers: Amyloid Precursor Protein (APP), Clusterin, and Glial Fibrillary Acidic Protein (GFAP). The MMOF platform provides a high-surface-area, magnetically responsive scaffold that enables efficient immobilization of primary antibodies, while MoS₂ QDs, carbon quantum dots (CQDs), and CdSe/ZnS QDs act as spectrally distinct RET acceptors, facilitating clean and interference-free multiplexed ECL readout from a single TCPO-triggered excitation event. Under optimized analytical conditions, the biosensor displayed strong, concentration-dependent ECL responses across a wide dynamic range (40 ng/mL down to 0.0004 ng/mL). The calculated limits of detection demonstrated excellent sensitivity, achieving 0.67 pg/mL for APP, 0.92 pg/mL for Clusterin, and 0.54 pg/mL for GFAP, confirming the platform’s capability to quantify trace-level biomarkers far below their physiological concentrations. This remarkable performance arises from the highly efficient CRET mechanism between TCPO high-energy intermediates and the QD emitters, further enhanced by the synergistic dual co-reactant system (H₂O₂/APS). Figure 1