Figure 4.

Ex vivo fluorescence imaging of frozen tissue sections confirms the co-localization of GFP (green, left image), perfusing blood vessels (Hoechst, blue, left image), and PpIX fluorescence (red, right image). Due to the nature of the filter, some Hoechst fluorescence leaked into the GFP channel; therefore, these regions are marked with white arrows and indicate areas that contain fluorescence from both the green and blue fluorescence channels and can be attributed to perfusive blood vessels. Scale bar = 200 μm.