Figure 2

Microscopic images of the Human bronchial epithelial (HBE) cells exposed to clean air. (a) Optical setup for oblique illumination microscopy. (b) Image obtained by axial illumination, and (c) oblique illumination. (d) Optical setup for fluorescence imaging. (e) Cell nuclei stained by Hoechst 33342, and (f) Cell membrane is stained by Calcein.