Fig. 2

In vitro cellular uptake and biocompatibility. (A, B) Cellular uptake of RNPs and RMPs by primary articular chondrocytes measured by flow cytometry (n = 3). (C) Cellular uptake of RNPs and RMPs visualized by CLSM, Scale Bar 20 μm. (D) Cell viability of primary articular chondrocytes cultured with different concentrations of NPs measured by CCK8 assay (n = 4). (E) Cell viability of primary articular chondrocytes cultured with different concentrations of free rapamycin and RNPs measured by CCK8 assay at 48 h (n = 4). (F) Fluorescence images of Live/Dead staining on primary articular chondrocytes cultured with different concentrations of free rapamycin and RNPs, Scale Bar 500 μm. Statistical analysis was performed using one-way ANOVA with Tukey’s post hoc analysis. Data are presented as means ± SD. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001