Uptake of LBPNS and SBPNS by cells. (a) Fluorescence confocal pictures of SBPNS-BSA-FITC and LBPNS-BSA-FITC inside the cell membrane. (b–d) Percentage of FITC-positive cells to total cell number in SBPNS-BSA-FITC and LBPNS-BSA-FITC (2.5, 5.0, and 10.0 μg/mL) exposed cells detected by flow cytometry (n = 3). (e) Percentage of FITC-positive cells to total cell number exposed to different concentrations of SBPNS-BSA-FITC and LBPNS-BSA-FITC for 34 h detected by flow cytometry (n = 3). (f) Percentage of FITC-positive cells to total cell number in different inhibitor-treated groups after 12 h exposure to 10 μg/mL SBPNS-BSA-FITC (n = 3). (g) Percentage of FITC-positive cells to total cell number in different inhibitor-treated groups after 12 h exposure to 10 μg/mL LBPNS-BSA-FITC (n = 3).