Separation of breast cancer cells from peripherally circulating blood using antibodies fixed in micro-channels

Bio-Micro Electro Mechanical System (Bio-MEMS) technology was applied to the problem of early breast cancer detection and diagnosis. A micro-device is being developed to identify and specifically collect tumor cells of low abundance (1 tumor cell among 107 normal blood cells) from circulating whole blood. By immobilizing anti-EpCAM (Epithelial Cell Adhesion Molecule) antibodies on polymer micro-channel walls by chemically modifying the surface of the PMMA, breast cancer cells from the MCF-7 cell line, which over-express EpCAM, were selected from a sample volume by the strong binding affinity between the antibody and antigen. To validate the capture of the breast cancer cells, three fluorochrome markers, each identified by a separate color, were used to reliably identify the cancer cells. The cancer cells were defined by DAPI + (blue), CD45 - and the FITC-cell membrane linker + (green). White blood cells, which may interfere in the detection of the cancer cells, were identified by DAPI + (blue), CD45 + (red), and the FITC-cell membrane linker + (green). EpCAM/anti-EpCAM binding models from the literature were used to estimate an optimal velocity, 2mm/sec, for maximizing the number of cells binding and the critical binding force. At higher velocities, shear forces (\u3e 0.48 dyne) will break existing bonds and prevent the formation of new ones. This detection micro-device can be assembled with other lab-on-a-chip components for follow-up gene and protein analysis