Real-time optical live/dead assay for mouse NPCs using microfluidics. (A) Schematic drawing of a fluidic network containing control and gradient region. (B-C) Mouse NPCs cultured in the control region of fluidic channel. Hydrogen peroxide (50 mM) was added into the right reservoir after preloading with propidium iodide (red). Cell death resulting from exposure to hydrogen peroxide was monitored by time-lapse microscopy. (D-E) Numbers of PI-positive cells increase towards the right side of the gradient chamber with longer exposure to hydrogen peroxide. Quantitative analysis of cell death in the control (F) and gradient region (G). Each bar shows the average for three independent experiments with standard errors of mean (*p < 0.05, **p < 0.01). Scale bars are 100 μm.