Figures & data
Figure 1 Preparation and analysis of morphology of HCSs. (A) Schematic representation of HCS preparation. (B) SEM image of HCS (insert scale bar, 200 nm). (C) TEM image of HCS (insert scale bar, 200 nm [left] and 100 nm [right]).
Abbreviations: HCS, hollow carbon sphere; SEM, scanning electron microscopy; TEM, transmission electron microscopy.
![Figure 1 Preparation and analysis of morphology of HCSs. (A) Schematic representation of HCS preparation. (B) SEM image of HCS (insert scale bar, 200 nm). (C) TEM image of HCS (insert scale bar, 200 nm [left] and 100 nm [right]).Abbreviations: HCS, hollow carbon sphere; SEM, scanning electron microscopy; TEM, transmission electron microscopy.](/cms/asset/7042caf8-1990-4a41-9818-9f0db564f28f/dijn_a_12193763_f0001_c.jpg)
Figure 2 Characterization of HCSs. Analysis of (A) size distribution of HCSs and (B) surface zeta potential.
Abbreviation: HCS, hollow carbon sphere.
Figure 3 Structural characterization of HCSs. Properties of HCSs analyzed using (A) Raman spectroscopy and (B) FTIR spectroscopy.
Abbreviation: HCS, hollow carbon sphere.
Figure 4 Internalization of HCSs. (A) Internalization of Cy5.5–HCSs in Eca109 cells examined using FACS. (B) Analysis of the potential mechanism of Cy5.5–HCS endocytosis in Eca109 cells. (C) Effect of pH on the uptake of HCSs by Eca109 cells.
Abbreviations: HCS, hollow carbon sphere; FACS, fluorescence-activated cell sorting.
Figure 5 Localization of HCSs in cells. (A) Cy5.5-labeled HCSs were prepared and the fluorescent signals were measured using an in vivo imaging system. (B) Eca109 cells treated with Cy5.5–HCSs (green) and marked with LysoTracker (red). Scale bar =10 μm.
Abbreviation: HCS, hollow carbon sphere.
Figure 6 Toxicity of HCSs. (A) In vitro cell proliferation assay to evaluate the cytotoxicity of HCSs. In vivo toxicity assay for analyzing (B) body weight and (C) blood cells chemistry in mice.
Abbreviation: HCS, hollow carbon sphere.
Figure 7 Drug-loading capacity and drug-releasing profile of HCSs. (A) Solid CSs and HCSs loaded with Dox were prepared and photographed. (B) Calculation of the loading percentage of Dox and the difference in loading capacity between CSs and HCSs. HCSs displayed more efficient drug-loading capacity. (C) Measurement of cumulative release of Dox from HCS–Dox evaluated at pH 5.5–7.4. *p<0.05, **p<0.01.
Abbreviations: HCS, hollow carbon sphere; CS, carbon sphere; Dox, doxorubicin.
Figure 8 Biodistribution and circulation time of HCSs. (A) Cy5.5-labeled HCSs were prepared and i.v. injected into the Eca109 tumor-bearing mice, and the whole mouse body was scanned using an in vivo imaging system. The (B) circulation time and (C) quantity of Dox in peripheral blood were analyzed at different time points after HCS–Dox administration. (D) Distribution of Dox in different organs of the mice including liver, spleen, heart, lung, kidney, brain, and tumor tissues. *p<0.05; **p<0.01.
Abbreviations: HCS, hollow carbon sphere; i.v., intravenously; Dox, doxorubicin.
Figure 9 In vivo antitumor activity. An esophageal cancer xenograft model was established to verify the application of HCSs in cancer therapy. (A) Protocol for tumor implantation and treatment. Measurement of (B) tumor volume and (C) survival at 3-day intervals in tumor-bearing mice, monitored for 60 days. *p<0.05; **p<0.01; ***p<0.001.
Abbreviations: HCS, hollow carbon sphere; Dox, doxorubicin; ns, not significant.
