Aptamer-functionalized 3D gold nanodendrite platform for electrochemical detection of circulating tumor cells in breast cancer

= 0.998). Selectivity tests showed negligible responses (<5%) toward HeLa and Jurkat cells, while reproducibility across five electrodes yielded a relative standard deviation of 3.5%. Stability evaluation demonstrated retention of 92.5% activity after 28 days of storage at 4 °C. Recovery studies in 10% human serum spiked with MCF-7 cells (as a model CTC system) showed excellent accuracy (96.5-104.2%) with RSD ≤ 4.5%. Collectively, these results demonstrate strong analytical performance for MCF-7 model CTCs in buffered suspensions and in a spiked (10%) serum matrix, supporting the AuND/dual-aptamer platform as a proof-of-concept CTC biosensing strategy; validation using patient-derived CTCs in whole-blood samples will be required in future studies to establish clinical utility.