Electrochemical Quantification of Parathyroid Hormone Using an Aptamer-Functionalized Magnetic Nanoparticle System

In this study, we developed a highly sensitive and specific aptamer-based electrochemical biosensor for the quantitative analysis of parathyroid hormone (PTH) for intraoperative parathormone (ioPTH) analysis. By leveraging the intrinsic electrochemical activity of PTH, a direct detection method was first optimized on carbon screen-printed electrodes (SPEs). The biosensor's performance was then significantly enhanced by using aptamer-functionalized magnetic nanoparticles, which selectively captured and enriched the PTH target from complex matrices. The developed method demonstrated a low limit of detection (LOD) of 1.9 pg/mL and a wide linear range of 5-400 pg/mL, validating its high sensitivity and broad applicability for clinical use. The biosensor also exhibited high specificity against common interferents in biological fluids and excellent long-term stability, retaining over 75% of its initial activity for 3 months. Clinical validation using real patient serum samples showed a high correlation of up to 96.72% with a commercial ELISA kit, confirming the biosensor's reliability as a rapid, accurate diagnostic tool. The successful integration of aptamer technology with a practical electrochemical platform offers a promising alternative to conventional immunoassays for real-time, point-of-care PTH monitoring.