Figure 4
From: Membrane-less microfiltration using inertial microfluidics
Results demonstrating the effectiveness of the inertial filtration system for cell synchronization.
(a) Left to right: Optical image of original cell population before sorting. CHO cells present displayed a range of sizes i.e. 11–20 μm. Optical image showing CHO cells arrested in G2/M phase with Nocodazole. Cell sizes were 18 ± 2 μm. Optical image showing CHO cells arrested in G0/G1 phase via contact inhibition. Cell sizes were 11 ± 2 μm. (b) Top & bottom: optical image showing CHO cells in the inner and outer outlets respectively after separation with their sizes compared to 10 μm beads at 1.5 mL/min. The cells at the inner outlet have larger sizes while that in the outer outlet have smaller sizes. (c) The positive slope of the forward and side scatter graphs indicated the correlation between cell size and cell-cycle phase. (d) Left: histogram of the DNA content showed that before sorting, the G0/G1:G2/M ratio was 1.82:1. Distinct peaks could be observed for cells in the G0/G1 and G2/M phase by their DNA content stained with Hoechst. Right: after sorting at 1.5 mL/min (1 × 106 cells/mL), the G0/G1:G2/M ratio improved close to three folds to 5.02:1 in the outer outlet. The G0/G1 purity in the outer outlet was ~ 80%, an improvement from ~ 60% in the unsorted sample. The increase in cell count in the outer outlet also indicated selective enrichment of cell population with lower DNA content in the G1 phase. This can be further improved by processing output from the inner outlet again (2nd or 3rd cycles).
