Precise detection of telomerase reverse transcriptase C228T mutation using label-free and magnetically induced...

Telomerase reverse transcriptase promoter C228T mutations (TERT_C228T) are strongly associated with poor outcomes in papillary thyroid cancer, necessitating sensitive detection methods. In this work, a "Signal-off" type of label-free and magnetically induced self-assembly electrochemical biosensors based on α-Fe₂O₃/Fe₃O₄@Au magnetic nanocomposites (MNCs) were developed for TERT_C228T detection. Thiolated aptamers (Apts) for specific recognition of TERT_C228T were immobilized on α-Fe₂O₃/Fe₃O₄@Au MNCs via AuS bonds, and bovine serum albumins (BSA) were employed to block non-specific sites and form α-Fe₂O₃/Fe₃O₄@Au-Apt/BSA biosensors. TERT_C228T specifically hybridized with Apts, forming a rigid dsDNA film on the electrode. Enhanced steric hindrance and electrostatic repulsion suppressed electron transfer of [Fe(CN)₆]^3-/4-, leading to decreased current signals. The biosensors were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry, the results demonstrated that the biosensors exhibited a wide linear range (10² pM- 10⁶ pM), high sensitivity (LOD of 0.67 pM), and excellent selectivity, along with high reproducibility (RSD = 1.84%) and long-term stability (signal retention above 95% within 10 days), and enabled reliable detection in diluted human serum (recoveries of 98.1%-107.3%). Overall, the electrochemical biosensors offer a simple, rapid, and ultrasensitive platform for TERT_C228T detection, with promising potential for molecular diagnosis and thyroid cancer risk stratification.