Fig. 5

Evaluation of the toxicity in vivo. a Schematic illustration of the treatment. The SiO₂ (2.4 nm) and Au (4.1 nm) and Fe₃O₄ (2.3, 4.2, and 9.3 nm) NPs were intravenously injected at a dosage of 100 mg/kg. b Survival rates of the mice over a period of 24 h after intravenous injection. c Quantitative determination of iron in different organs obtained by ICP-AES showing the biodistribution of Fe₃O₄ NPs (n = 3). The concentration of total ROS in serum (d), heart (e), liver (f), spleen (g), lung (h) and kidney (i) after intravenous injection of different-sized Fe₃O₄, SiO₂ and Au NPs (100 mg/kg) for 2 h. The ROS was determined using DCFH as an indicator. All of the data were presented as the mean ± SD (n = 3). P values: *P < 0.05, **P < 0.01 and ***P < 0.001 compared with the corresponding control group