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, R-ct, in EIS experiments. R-ct 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 +/- 50cells/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.