Fig. 2

In vitro cellular evaluation. Cell cytotoxicity of TKCP against chondrocytes (a) and the effect of TKCP@DEX on chondrocytes (b) determined by the CCK-8 assay after incubating for 24 or 48 h. c Cell viability of MIA-induced chondrocytes pretreated with culture medium only, DEX, CAPP@DEX, TKP@DEX or TKCP@DEX for 24 h. d The hemolysis ratio of TKCP@DEX at different concentrations. e The cellular uptake of TKCP, TKP or CAPP NPs in normal chondrocytes, MIA-induced OA chondrocytes and in the presence of ROS inhibitor (NAC) for 24 h. The nuclei were counterstained with DAPI (blue). f Quantification of fluorescence after incubation with TKCP for different concentrations of MIA (3 μM and 6 μM) or with ROS inhibitor (NAC) for 24 h. g Quantification of fluorescence after incubation with TKCP, TKP or CAPP NPs in the presence of MIA (3 μM) for 24 h. Flow cytometry analysis (h) the production of intracellular ROS in chondrocytes at different concentrations of MIA (3 μM and 6 μM) or with ROS inhibitor (NAC) after incubation for 24 h. Scale bars: 100 µm. (n = 3; mean ± SD; *, # indicate p < 0.05; **, ## indicate p < 0.01; ***, ### indicate p < 0.001.)