Thursday, May 2, 2013
Isolating CTCs. The
circulating tumor cell (CTC)-iChip uses magnetic beads to label cells in whole
blood. The blood sample is loaded onto the chip, on which lateral displacement,
inertial focusing and magnetophoresis separate and collect the cells of
interest from the bulk.
Positive selection incorporates epithelial cell adhesion molecule
beads to bind CTCs, and (II) negative depletion incorporates common
leukocyte antigen CD45-binding
and granulocyte marker CD15
4 a1,3 fucosyltransferase myeloid-specific; FUT4;
magnetic beads to bind white blood cells (WBCs).
lateral displacement, the sample moves through an array of microposts, spaced
32 mm apart, which results in size-based
separation and retention of nucleated cells. Red blood cells (RBCs), platelets
and other components exit the device.
inertial focusing, the nucleated cells enter an asymmetrical, curved channel
and exit as a tight row of individual cells.
with magnetophoresis, a magnetic field (ÑB) separates magnetically labeled cells from unlabeled
cells and provides an isolated supply of CTCs in solution.
the device can process about 8 mL of whole blood per hour, translating to about
107 total cells per second. (Figure based on Figure 1a in ref. 1.)