Fig. 4

Cytotoxic activity of the LEV-NPs at different drug concentrations on RAW264.7 cells. The cytotoxicity of LEV-NPs to RWA264.7 was measured after RAW264.7 cells were treated with LEV-NPs for 4 h and then cultured for another 24 h. Compared with the LEV + US, ^**P < 0.05. The experiments were performed in triplicate; mean ± SD are shown