To evaluate the possibility of correlative contrast, the grid was imaged on an Olympus IX73 inverted light microscope. Fluorescence images were taken with 355 nm excitation light in the epi direction with a 405 nm long pass filter to remove excitation light. The fluorescent images that correlate to the region of the ZnSe NPs are shown in Figure , panel C. Figure , panel D shows an overlay of panels B and C. In this panel, α-SeNPs prior to reaction are shown in red, ZnSe particles formed after the reaction in white, and the fluorescence signal is shown in blue.