Intracellular drug delivery of the hybrid PLA NPs/MMC-SPC. Confocal laser scanning microscopy images of H22 cells incubated with the (A,B,C) coumarin-6-PLA NPs/FITC-MMC-SPC and (D,E,F) coumarin-6-PLA NPs/FITC-MMC at the equivalent coumarin-6 concentration for 12 h at 37°C. (A,D) Left column showed the red fluorescence from the cytoskeleton (the cell nuclei were stained with rhodamine-phalloidin). (B,E) Middle column showed the green fluorescence from the drugs (the drugs were labeled with FITC). The merged image of the images in left column and middle column is shown in (E,F) right column. The nuclei were stained with Hoechst 33258 (Sigma-Aldrich, St. Louis, MO, USA) (blue).