| Abstract: | A simple and rapid electrochemical aptamer cytosensor has been developed for direct detection of chronic myelogenous leukemia (CML) K562 cells based on a specific aptamer and a biotin conjugated concanavalin A (bio‐ConA) detection probe. The K562 cell could be specifically recognized by T2‐KK1B10 capture aptamer pre‐immobilized on gold modified electrode surface. Then, bio‐ConA was added in the reaction to identify K562 cell surface mannose, resulting in an aptamer‐K562 cell‐bio‐ConA sandwich complex. Finally, streptavidin conjugated alkaline phosphatase (ST‐ALP) combined with the bio‐ConA to catalyze α‐naphthyl (α‐NP) phosphate to form α‐naphthol which is highly electroactive at an operating voltage of 180 mV (vs. Ag/AgCl). Under optimum conditions, the DPV signals were proportional to the logarithm of K562 cell from 1×102 to 1×107 cells mL−1 with a detection limit of 79 cells mL−1. The cytosensor also exhibited high selectivity, stability and reproducibility. When applied to detect K562 cells in human blood samples, recoveries between 79.6 %–93.3 % were obtained, indicating the developed biosensor would be a potential alternative tool for CML K562 cell detection in real biological samples. |
