Fig. 4. Dose-dependent SERS images of (A) PSMA+ PC3 PIP and (B) PSMA– PC3 flu cells following incubation in various concentrations (10, 20, 30 and 50 pM) of SERS agents. The SERS images were overlaid with bright-field images to aid understanding of the spatial localization of the agents. (C) Concentration-dependent SERS intensity determined by averaging the SERS intensity over the pixels on a single cell. The SERS images were constructed on the basis of the integrated intensity of the 1340 cm^–1 Raman band.