Figure 4  The effect of affinity on cell-ligand spot binding: PSMA-positive LNCaP cells and PSMA-negative PC3 cells were labeled with 700 nm and 800 nm NIR fluorophores and pseudo-colored in red and green, respectively. (A) Chemical structures of targeting ligands employed, (B) 4× microscopy images, and (C) 20× microscopy images. Scale bars = 200 μm.