We also examined the endocytosis of PQDs and prepared nanoprobes such as BRCAA1 antibody-PQDs in MGC803 cells. In endocytosis, the PQDs were distributed in the cytoplasm as granules and colocalized almost completely in selleck chemical endocytic vesicles (red circles in Figure 8a,c); this indicates that the PQDs were internalized by endocytosis pathway. Regarding targeted labeling, the BRCAA1 antibody-PQD probes were distributed evenly in the cytoplasm (blue arrows in Figure 8b,d), and this
was consistent with microscopic and selleckchem confocal images mentioned above. The TEM images certified that the synthesized PQD-antibody probes can target and image the MGC803 cell specially. Figure MM-102 supplier 7 Confocal micrographs of MGC803 cell target-labeled with the BRCAA1-antibody PQD probes. (a) Bright field, (b) cytoplasm labeled by PQDs, (c) nucleus stained by DAPI, (d) cosituated picture of cells and fluorescence. (a-d) Scale bars are 25 μm. (e) Z/X- and Z/Y-sections reconstructed from a confocal series through representative cells. (f) Three-dimensional reconstruction of representative
cells. (e-f) Scale bar represents 5 μm. Fourteen sections of 990 nm were taken for each series, and Z-sections were reconstructed with Imaris™ software. Z-sections were taken at a line running through the midpoint of the XY plane. Figure 8 TEM images of endocytosis of PQDs and single molecule labeling with PQD-antibody probes in
MGC803 cell. (a, c) TEM images of general labeling with PQDs; the red circles enclose PQD granules endocytosed by MGC803 cells. (b, d) Targeted single molecule labeling with synthesized PQD-antibody probes; the blue arrows pointed out the evenly distributed biomolecule probes in the cytoplasm of the MGC803 cell. BRCAA1 monoclonal antibody-conjugated QDs for in vivo targeted imaging For in vivo imaging, it is important to estimate the parameters of fluorescence intensity and the labeled cells; those after that, the optimum number of the labeled cells can be decided for in vivo imaging. From Figure 9a,b, we can see that there is a linear increase with the number of PQD (red)-labeled MGC803 cells from 2 × 102 up to 2,048 × 102, but the system appears to become saturated when greater numbers of cells are introduced. Figure 9 Sensitivity and capability of PQDs (red)-labeled MGC803 cell imaging in live animals. (a, b) The quantitative analysis of fluorescence of PQD-labeled MGC803 cells showed a linear relationship (R 2 = 0.98777) between fluorescence intensity and cell numbers. (c) Fluorescence imaging of different amounts of PQD-labeled MGC803 cells injected subcutaneously in a mouse (cell numbers of 32× 102, 128× 102, 512× 102, and 2,048 × 102 corresponded to the sites 1, 2, 3, and 4 marked in the image; excitation filter 410 nm, emission filter 700 ± 15 nm, band pass).