Fig. 5
ODMR contrast of NDs internalized in cells. a Fluorescence image of 156 nm NDs internalized in macrophage cells; the white square delineates the ROIs from which signals were extracted. NDs internalized within cells show inhomogeneous aggregation and concentration, resulting in a region-dependent FL values. ODMR spectra presenting the NV− central lines (AL and AR) and the 13C sidebands (BL and BR) at different laser power with constant MW power are shown in b for a single cell, and in c for a cellular aggregate. d ODMR curves corresponding to the ROIs of panel (a). The caption reports the average value of fluorescence intensity in each ROI. ODMR contrast steadily increases to 8.1 mW, while at higher laser powers it shows a plurality of behaviors. Small differences in the curves are uncorrelated with the average FL intensity and are supposedly related to local environment. e A color-saturated fluorescence image of 156 nm NDs internalized in cells. The selected ROI f shows a cell with its different compartments and its nucleus. g Map of the distribution of ODMR contrast within the cells of (f). Contrast varies regionally, with an average value of 4.5%