Electrochemiluminescent magnetic biosensor for simultaneous microRNA and parathyroid hormone detection via resonance energy transfer

Thyroid-related malignancies often involve both oncogenic alterations and endocrine imbalance, necessitating integrated biomarker monitoring. In this work, we report an electrochemiluminescent (ECL) magnetic biosensor for the simultaneous detection of microRNA (miR) and parathyroid hormone (PTH), two clinically relevant indicators of thyroid cancer and parathyroid dysfunction. The sensing platform leverages luminol as an ECL donor and organic dyes as energy acceptors within a chemiluminescence resonance energy transfer (CRET) framework, enabling excitation-free signal generation with low background interference. Surface-modified magnetic nanoparticles serve as dual-function carriers, facilitating efficient magnetic enrichment and high-affinity target recognition. The system achieves sensitive and specific dual-analyte detection in a single assay with broad linear ranges and rapid turnaround. Limits of detection in human serum were 0.38 fM for miR-222 and 0.22 pg/mL for PTH. This CRET-ECL magnetic biosensor offers a rapid, sensitive, and minimally invasive approach for point-of-care evaluation of thyroid malignancy and associated endocrine disorders.