Magnetic immobilization and electrochemical detection of leukemia K562 cells

A new protocol was proposed for rapid magnetic isolation, immobilization and electrochemical detection of leukemia K562 cells via their decoration with cationic magnetic nanoparticles (CMNPs). The CMNPs (3-aminopropyltriethoxysilane-treated Fe₃O₄) were synthesized in liquid solution and characterized by transmission electron microscopy. After the incubation of pre-cultured leukemia K562 cells in the coexistence of CMNPs for a period of time, the CMNPs modified living cells could be rapidly isolated from the medium and immobilized firmly on the electrode surface via a magnetic field, as traced by quartz crystal microbalance. The cyclic voltammetric experiments of the cells immobilized at glassy carbon electrode exhibited an irreversible anodic current peak whose height is proportional to cell viability, and the 5-fluorouracil cytotoxicity results obtained from the proposed magnetic-electrochemical method were supported by conventional MTT assays. The proposed method is simple, rapid, inexpensive, and convenient in electrode renewal, which is recommended as a promising experimental platform for wider applications in biosensing and cellular researches.