Electrochemical assay for detection of circulating tumor cells based on LiFePO4 as electrochemical probe.

• Electrochemical sensor for detecting circulating tumor cells is reported. • Fe 3 O 4 magnetic nanospheres were utilized to capture MCF-7 cell. • LiFePO 4 particles were chosen as electrochemical label. • Electrochemical signals are generated by reaction of LiFePO 4 with molybdate. • The sensor was applied for detection of tumor cells in blood sample. In this study, we reported an electrochemical assay for detecting circulating tumor cells (CTCs) in whole blood. Breast cancer cell MCF-7 was chosen as a model for study. Fe 3 O 4 magnetic nanospheres (MNs) modified with anti-epithelial cell adhesion molecule (EpCAM) antibody were utilized to capture MCF-7 from samples and gold nanoparticles modified LiFePO 4 (LiFePO 4 /Au) particles were chosen as electrochemical label. Aptamer can be linked onto LiFePO 4 /Au via Au-S bond, and then the LiFePO 4 /Au-aptamer complex can specifically bind to the MUC1 protein that is over-expressed on the cell surface of MCF-7. Electrochemical signals are generated by the reaction of phosphate in LiFePO 4 with molybdate to form redox molybdophosphate. The utilization of LiFePO 4 for signal probe may expand the application of LiFePO 4 in biosensing fields. [ABSTRACT FROM AUTHOR]