Enrichment of circulating tumor cells using a centrifugal affinity plate system

• We introduce a centrifugal affinity plate (CAP) system designed for capturing CTCs.
• Centrifugal force improves the collision chance between CTCs and channel surface.
• The CAP system is able to handle 1–5 ml of whole blood samples within 10 min.
• We obtained a high capture efficiency (70%∼), keeping captured CTCs alive.
• The CAP system is expected to be useful in the diagnosis and prognosis of cancers.

Circulating tumor cells (CTCs) are defined as cells that have detached from a primary tumor and are circulating in the bloodstream. Their isolation and quantification is of great value for cancer prognoses and drug testing. Here, the development of a centrifugal affinity plate (CAP) system is described, in which centrifugal force and antibody-based capture are exploited to enrich CTCs on one plate and hematological cells on the other. The CAP is rotated to exert centrifugal force on the cells in a blood sample, quickly transporting them to the anti-epithelial adhesion molecule (EpCAM)-coated and anti-CD45-coated surface of the CAP to shorten the reaction time and increase the adhesion force between the tumor and blood cells and each antibody. The effect of a rotating process on cell capture was investigated, and the capture efficiency was demonstrated using blood samples from healthy donors spiked with human non-small cell lung cancer (NCI-H1650) and breast cancer (MCF-7) cells. The CAP system was capable of rapid isolation and identification of CTCs without the requirement for pretreatment of blood samples. Finally, the CAP system was tested to evaluate the detection efficiency of CTCs in the blood samples of breast cancer patients. The number of captured CTCs in only 1 ml of blood varied from 6 to 10.