Circulating Tumor Cells: Capture with a Micromachined Device
The isolation and analysis of circulating tumor cells from blood is the subject of intense research. Tests to detect metastasis are available, but progress has been hampered by the lack of tumor-specific markers and predictable DNA abnormalities. CTCs from solid tumors can be separated from normal hematopoietic cells based on size and other inherent physical and biological properties. The main challenge in this endeavor is the small number of available cells of interest, 1-2 per ml in human whole blood. A micromachined device for fractioning whole blood using physical methods to enrich and/or isolate rare cell types from peripheral circulation has been designed. It has four segments of microfluidic channels, each consisting of a 2-D array of columns. The gap between the columns progressively narrows across the device. Current devices have channels ranging in width from 20µm down to 5µm, and in depth from 20µm down to 5µm. When healthy adult blood, spiked with cells from each of eight cancer cell lines tested, was loaded into the device, all cancerous cells were retained in a well-defined area of the device, while blood cells migrated to the output reservoir. Use of these devices will advance non-invasive methods used to monitor patients, stage disease, and assess treatment. Furthermore, insights into metastasis will be gained.