Figures & data
Figure 1 A representative illustration of the synthesis system and SCNs before or after drug loading.
Abbreviations: SCNs, strontium carbonate nanoparticles; ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 2 SEM images of engineered SCNs with different enlarging ratios.
Abbreviations: SEM, scanning electron microscope; SCNs, strontium carbonate nanoparticles.
Figure 3 XRD pattern of engineered SCNs and standard pattern of SrCO3 (JCPDS 05-0418).
Abbreviations: XRD, X-ray diffraction; SCNs, strontium carbonate nanoparticles.
Figure 4 Particle size distribution of SCNs.
Abbreviation: SCNs, strontium carbonate nanoparticles.
Figure 5 UV-vis spectra for SCNs, free etoposide and ESCNs.
Abbreviations: UV-vis, ultraviolet-visible spectroscopy; SCNs, strontium carbonate nanoparticles; ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 6 FTIR spectra for (a) free etoposide, (b) ESCNs and (c) SCNs.
Abbreviations: FTIR, Fourier transform infrared spectroscopy; ESCNs, etoposide-loaded strontium carbonate nanoparticles; SCNs, strontium carbonate nanoparticles.
Figure 7 Sedimentation photographs of SCNs, free etoposide, and ESCNs in double distilled water after standing for 10 minutes, 3 hours, and 8 hours.
Abbreviations: SCNs, strontium carbonate nanoparticles; ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 8 Release profiles of etoposide from ESCNs under simulated physiological conditions. (A) Release profiles of etoposide from ESCNs under simulated physiological conditions (pH 3.0, pH 5.8, and pH 7.4 at 37°C); (B) release profiles in the initial 4 hours.
Note: All experiments were carried out in triplicate.
Abbreviation: ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 9 Titration curves of SCNs, free etoposide, and ESCNs.
Note: The abscissa represents the added volume of a 0.1 M HCl aqueous solution.
Abbreviations: SCNs, strontium carbonate nanoparticles; ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 10 (A and B) Growth inhibition assay results for HEK293T cell line with SCNs, free etoposide, and ESCNs after 24 and 48 hours of incubation. Graphs were plotted as particle concentrations of 5, 10, 20, and 40 μg/mL, respectively; (C and D) growth inhibition assay results for the SGC-7901 cell line with SCNs, free etoposide, and ESCNs after 24 and 48 hours of incubation.
Notes: Graphs were plotted as etoposide concentrations of 5, 10, 20, and 40 μg/mL, respectively. All experiments were carried out in triplicate.
Abbreviations: SCNs, strontium carbonate nanoparticles; ESCNs, etoposide-loaded strontium carbonate nanoparticles.
Figure 11 FACS analysis of SGC-7901 cells stained with Annexin V-FITC and PI. (A) Cells were not treated with any agents for blank control; (B) apoptotic cells were induced by etoposide, (C) cells treated with the ESCNs.
Note: In all panels, LR represents early apoptosis and UR represents late apoptosis.
Abbreviations: FACS, fluorescence-activated cell sorting; PI, propidium iodide; ESCNs, etoposide-loaded strontium carbonate nanoparticles; LR, low right quadrant; UR, up right quadrant.
Figure 12 A representative illustration of pH-sensitive ESCNs targeting.
Abbreviations: ESCNs, etoposide-loaded strontium carbonate nanoparticles; EPR, enhanced permeability and retention.
