Fig. 2

Cellular uptake of Cy5-labeled NPs by HGC-27 cells and distribution of Cy5-labeled NPs in HGC-27 3D tumor spheroids. A Cellular uptake of Cy5-labeled NPs by HGC-27 cells after 2 or 6 h of treatment. CLSM images of HGC-27 cells incubated with Cy5 (1 μg/mL, red), Cy5-labeled CA-Oxi-αCD NPs or Cy5-labeled FA-CA-Oxi-αCD NPs (containing 1 μg/mL Cy5) for 2 or 6 h. Cell nuclei were stained with DAPI (blue). The scale bar represents 50 μm. B Distribution of Cy5-labeled NPs (red) in HGC-27 tumor spheroids. After 6 h of incubation, the tumor spheroids were observed in CLSM layer scanning mode. The cell nuclei were stained with DAPI (blue). The scale bar represents 200 μm. C Semiquantitative analysis of the corresponding Cy5 fluorescence intensity in A. D Distribution of Cy5-labeled NPs (red) in frozen tumor spheroid sections. Frozen tumor spheroid sections were observed via CLSM. The cell nuclei were stained with DAPI (blue). The scale bar represents 200 μm. E Semiquantitative analysis of the corresponding Cy5 fluorescence intensity in B. F Semiquantitative analysis of the corresponding Cy5 fluorescence intensity in D *, significantly different at p < 0.05; **, significantly different at p < 0.01; ***, significantly different at p < 0.001. ****, significantly different at p < 0.0001