LAUSR

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.