Figure 5.

Separation of LNCaP cells from leukocytes as a function of pitch. (a) After quantification of leukocyte background and setting a cut-off pitch at 60μm, LNCaP cells spiked into blood were separated and purified from the leukocyte background on a 10μm incremented chip under a 5Hz ratchet. (b) High purity separation of LNCaPs from leukocytes was achieved despite both populations shifting to higher pitches. The LNCaP majority equilibrated at the 70–100μm pitches peaking at 80μm while the leukocytes equilibrated between the 10–60μm pitches peaking at 50μm. (c) Purity, defined as the total number of LNCaPs to total cells, for each pitch was determined showing a maximum purity of 67±35% at the 80μm pitch. The cumulative population (Cu Pop) the spiked cells was determined by sequentially summing the spiked population beginning at the 10μm pitch and showed 26% of the spiked population equilibrated below the cut-off pitch.