Fig. 7.

Characterization of D8. a Stability in mouse serum. D8, ^LCDX, and ^DCDX were dissolved in distilled water (1 mg mL⁻¹) and were incubated with mouse serum. RP-HPLC was used to monitor and quantify peptide hydrolysis at predetermined time points. b ^DCDX and D8 competed the binding of DiI-loaded ^DCDX-Lip with Neuro 2a cells. c Transcytosis efficiency of DiI-loaded sLip, ^DCDX-sLip, and D8-sLip across the primary brain capillary endothelial cell monolayer. d Microscopic observation of brain distribution of liposomes. BALB/c mice was injected with DiI-loaded sLip, ^DCDX-sLip, and D8-sLip via tail vein and brains were dissected, frozen sectioned, and stained with anti-CD31 antibody and DAPI 4 h post injection, blue—nuclei, green—blood vessels, and red—DiI dye, scale bar = 10 μm. e Positive DiI area in three random areas were counted by Image Pro. Scale bar = 20 μm, n = 3, data are means ± s.d. Statistical significances were calculated by Student’s t-test.*p < 0.05, **p < 0.01, ***p < 0.001