Development of a Simple and Sensitive Quantum Dot Labeled Magnetic Immunoassay Method for Circulating Tumor Cell (MCF-7) Detection

The early detection of breast cancer is very important for women around the world. Early cancer detection can be carried out by detecting circulating tumor cells (CTCs). Here, we developed an easy, sensitive, and specific detection method involving magnetic isolation and subsequent quantum dot (QD) fluorescence detection. Magnetic beads and QDs, both coated with epithelial cell adhesion molecule (EpCAM) antibody, were used to isolate and label MCF-7 breast cancer cells from serum solution. The magnetic beads were then removed to avoid their quenching effect, thus significantly increasing the fluorescence signal. Our results show that we are able to detect as low as 10 MCF-7 cancer cells in 1 mL of human serum with 3 orders of magnitude of the linear dynamic range.