Figure 4.

The magnetic sifter. A, Isolation principle. A whole blood sample containing MNP‐labeled CTCs is pumped through the pores. The CTCs are captured at the edge of the pores where a high magnetic field gradient exists, while unlabeled cells pass through the pores. ⁹⁰  B, Isolation of CTCs in density gradient media. The blood sample is loaded onto a density gradient medium. The CTCs are separated by a magnetic field gradient and then collected by moving the magnet from the separation chamber to the collection chamber ⁹¹