At the Cell Counter: PC-12 Cells

Figure 1. StainFree technology compared to fluorescence cell counting

PC-12 cells counted using StainFree™ Cell Detection Technology (blue circles) and red nuclear stain (red circles). Counts obtained from both methods agree closely, demonstrating that StainFree technology gives accurate cell counts while eliminating the need for fluorescent dyes (r2 > 0.99 for each plot).

Figure 2. Growth curves obtained using StainFree covered area analysis

Growth curves of PC-12 cells over a ten-day period. Cells were originally seeded at 2000 cells (red), 1000 cells (green), 500 cells (blue), and 200 cells (purple). Cell confluence was measured every 24 hours using the Field Analysis feature in SoftMax Pro Software. The observed dip in confluence for the 2000-cell initial density population at 144 hours (*) is likely due to depletion of nutrients in the culture medium; medium was originally replaced every three days, but from 144 hours onward it was replaced daily.

Figure 3. StainFree analysis of PC-12 cells with mitochondrial staining

Top row shows transmitted light images overlaid with red fluorescent (mitochondrial) images. Bottom row shows StainFree analysis with individual cells (purple masks) identified by the software. Left, untreated cells; right, cells treated with 1 µM valinomycin. For each individual cell identified, the intensity of mitochondrial staining could be calculated.

Figure 4. IC50 curves for PC-12 cells treated with valinomycin

PC-12 cells were treated with valinomycin and assayed for mitochondrial activity using MitoTracker™ Deep Red FM (MTDR) dye. Concentration-dependent response curves are shown for cells analyzed using StainFree Technology (blue) or fluorescent nuclear staining (green) to identify individual cells. Average mitochondrial fluorescence per cell is graphed vs. concentration of valinomycin. Nearly identical curves were obtained with both analysis methods, and in both cases the IC50 value was 57 nM.