In vitro cytotoxicity of SiO₂ or ZnO nanoparticles with different sizes and surface charges on U373MG human glioblastoma cells

Figures & data

Table 1 The IC₅₀ values for the cytotoxicity of SiO₂ or ZnO NPs against U373MG cells at 24 hours

NPs	IC50(μg/mL)
ZnO^AE100(+)	19.67±0.78
ZnO^AE100(−)	20.47±0.84
ZnO^SM20(+)	16.82±0.42
ZnO^SM20(−)	19.67±1.85
SiO2^EN100(R)	4,360.0±0.10
SiO2^EN100(−)	4,930.0±0.16
SiO2^EN20(R)	410.0±0.01
SiO2^EN20(−)	680.0±0.03

Abbreviations: IC₅₀, half-maximal inhibitory concentration; NPs, nanoparticles; SiO₂, silicon dioxide; ZnO, zinc oxide.

Figure 1 The effect of SiO₂ NPs on the viability of U373MG cells.

Notes: U373MG cells were treated with various concentration of (A) SiO₂^EN100(R), (B) SiO₂^EN100(−), (C) SiO₂^EN20(R), or (D) SiO₂^EN20(−) NPs. At 24 hours after treatment, cell viability was determined with the CellTiter-Glo assay. To calculate the relative luciferase activities, the luciferase activities at 0 hours after treatment were set to 100%. The data shown here represent the results from three independent experiments.

Abbreviations: NPs, nanoparticles; RLU, relative luminescence units; SiO₂, silicon dioxide.

Figure 2 The effect of ZnO NPs on the viability of U373MG cells.

Notes: U373MG cells were treated with 0, 2, 5, 10, 15, or 20 μg/mL of (A) ZnO^AE100(+), (B) ZnO^AE100(−), (C) ZnO^SM20(+), or (D) ZnO^SM20(−) NPs. At 24 hours after treatment, cell viability was determined with the CellTiter-Glo assay. To calculate the relative luciferase activities, the luciferase activities at 0 hours after treatment were set to 100%. The data shown here represent the results from three independent experiments. Significant differences between samples were determined by the P-value of a two-sample t-test (P<0.05).

Abbreviations: NPs, nanoparticles; RLU, relative luminescence units; ZnO, zinc oxide.

Figure 3 The effect of non-nano ZnCl₂ on the viability of U373MG cells.

Notes: U373MG cells were treated with or without 20 μg/mL ZnCl₂. At 24 hours after treatment, cell viability was determined with the Celltiter-Glo assay. To calculate the relative luciferase activities, the luciferase activities of mock-treated cells were set to 100%. The data shown here represent the results from three independent experiments.

Abbreviations: RLU, relative light unit; ZnCl₂, zinc chloride.

Figure 4 The effect of SiO₂ NPs on caspase activation.

Notes: U373MG cells were treated with 9 mg/mL of (A) SiO₂^EN100(R) or (B) SiO₂^EN100(−) NPs, or 0.8 mg/mL of (C) SiO₂^EN20(R) or (D) SiO₂^EN20(−) NPs. At 0, 1, 3, 6 and 9 hours after treatment, PARP cleavage was determined by Western blot analysis.

Abbreviations: NPs, nanoparticles; PARP, poly-(adenosine diphosphate-ribose) polymerase; SiO₂, silicon dioxide.

Figure 5 The effect of ZnO nanoparticles on caspase activation.

Notes: U373MG cells were treated with 20 μg/mL of (A) ZnO^AE100(−), (B) ZnO^SM20(−), (C) ZnO^AE100(+), or (D) ZnO^SM20(+) NPs. At 0, 1, 3, 6, 9 hours after treatment, PARP cleavage was determined by Western blot analysis.

Abbreviations: NPs, nanoparticles; PARP, poly-(adenosine diphosphate-ribose) polymerase; ZnO, zinc oxide.

Figure 6 The effect of SiO₂ or ZnO NPs on DNA fragmentation.

Notes: U373MG cells were treated with (A) SiO₂ or (B) ZnO NPs with different sizes and surface charges at the concentrations described above. At 6 hours after treatment, fragmented DNA was labeled with fluorescein-12-UTP (green) and visualized under fluorescence microscopy. Nuclei were visualized by DAPI staining (blue).

Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; NPs, nanoparticles; SiO₂, silicon dioxide; ZnO, zinc oxide; UTP, uridine triphosphate.