QDs coated with polyethylene glycol (PEG), CL1, or CL2 and siRNA are evenly distributed throughout the cytosol of HCT-116 cell, indicating that siRNA is efficiently delivered to the cytosol and detached from JB577. Scrambled siRNA labeled with Cy3 (green) was attached to QD-JB577 (red) with coating (a) PEG (b) CL1 (c) CL2 (d) CL4. Cells were transfected for 24, labeled with 4′,6-diamidino-2-phenylindole to visualize the nuclei (blue), then imaged with a 100×oil immersion lens.