Centrifugal Microfluidic Method Enables Better Circulating Tumor Cell Separation

Researchers in Korea have developed a new tool for rapidly isolating rare circulating tumor cells from patient blood samples. The microfluidic technique has the potential to improve cancer diagnosis and the ability to provide targeted and personalized treatments to patients.

Circulating tumor cells break off from cancers and are released into the blood stream. They can go on to form the seeds for new tumor formation in other parts of the body, known as metastases. From a diagnostic perspective, such cells represent the diversity of cancer cells found in the body, and isolation and identification can lead to more targeted therapies. Unfortunately, current techniques either miss some types of circulating cells or require specialized training and significant amounts of time to undertake.

The new technique developed at Daegu Gyeongbuk Institute of Science and Technology (DGIST) and CTCELLS, Inc., uses a fully automated centrifugation approach. Called Continuous Centrifugal Microfluidics – Circulating Tumor Cell Disc (CCM-CTCD), it involves placing a tube containing a blood sample in a machine with a spinning disc. The spinning, or centrifugal force, causes the blood to separate into layers containing different components, with the heavier red blood cells dropping to the bottom, lighter cells floating in a middle layer, and plasma settling at the top. After the disc begins to spin, a laser motor starts rotating at the same angular velocity and phase. This crucial step allows a laser to move and open a valve in the blood sample tube while the disc continues to spin, maintaining a thin layer of tumor and white blood cells, which are released into a separate chamber.

The chamber contains antibodies that specifically attach to and separate white blood cells from the mixture. This allows the circulating tumor cells in the mixture to flow on their own into a final chamber.

“Our smart and practical approach realizes a big dream in the field of liquid biopsy and demonstrates high performance across a wide range of cell types and different cancers with full automation,” adds Minseok S. Kim,  an Assistant Professor at the Department of New Biology at DGIST.

The team was able to go on to identify the different types of tumor cells and confirm by subsequent DNA testing that they represent the full diversity of different types of cells in the blood sample. They also used the technique on blood samples from patients with varying stages of lung cancer and found the number of circulating tumor cells in a sample correlated with the stage of disease progression. Identification of the types of tumor cells also allowed them to modify treatment strategies.

The results are discussed in more detail in a recent issue of the journal Theranostics. The group is now working on commercializing the technique for clinical use and hopes to expand its application to isolate other types of cells, including nerve, stem and immune cells.