Label‐free Electrochemical Aptasensor for Jurkat Cells Detection as a Potential Diagnostic Tool for Leukemia

Electrochemical impedance spectroscopy (EIS) and thickness shear mode acoustic method (TSM) have been used for development of the aptamer‐based biosensor for detection leukemic Jurkat cells. Thiolated DNA aptamers specific to the cancer marker protein tyrosine kinase‐7 (PTK7) have been chemisorbed on a gold surface. Redox probe [Fe(CN)6]3−/4− has been used for monitoring changes in charge transfer resistance, Rct, in EIS experiments. Rct increased with increasing the concentration of Jurkat cells. TSM allowed label‐free detection based on decrease of resonant frequency following addition of the cells. We obtained high sensitivity of Jurkat cells determination with limit of detection (LOD) 105±10 and 463±50 cells/mL for electrochemical and acoustic sensor, respectively. Small non‐specific interactions have been observed for control U266 cells which can be particularly due to the interaction of the aptamers with lipid part of the biomembranes.