Objective To prepare human vascular endothelial growth factor receptor 2 (VEGFR2)-targeted liquid perfluorocarbons-filled nanocapsules ultrasound contrast agent,and to investigate its ability of targeting human umbilical endothelial vein cells(HUEVC) and the peculiarity of the enhancing ultrasound imaging in vitro.Methods Rotary evaporation/emulsion technique was used to prepare biotinylated liquid perfluorocarbons-filled nanocapsules (LNCs).VEGFR2-tageted LNCs (V2-LNCs) was further made through conjugating the ligand (biotinylated anti-VEGFR2 antibody) to the surface of LNCs by biotin-avidin system and its appearance,distribution,size and zeta-potential properties were assessed.Immunofluorescent staining assay was used to identify the combination of ligand with the nanocapsules.The ability of V2-LNCs targeting with HUEVC in vitro was evaluated under the fluorescence microscope.Quantitative and statistical analysis were performed to evaluate the ultrasound contrast enhancement of the nanocapsules in vitro.Results The V2-LNCs are uniform and stabilized with size about (98.45 ± 0.07)nm.The ligation of antiVEGFR2 antibody and nanocapsules was positive in immunofluorescent straining assay.In vitro,targeting ability research showed the V2-LNCs could actively adhere to HUEVC,while the control was negative.At the same time,using anti-VEGFR2 antibody to pre-incubation with HUVEC could effectively block the interaction between V2-LNCs and HUEVC.The ultrasound images proved both V2-LNCs and LNCs can significantly enhanced ultrasound imaging contrast agent effect at a concentration of 5 mg/ml in vitro.Conclusions A stable VEGFR2-targeted liquid perfluorocarbons-filled nanocapsules was prepared successfully with biotin-avidin method and effectively bound to HUVEC specially in vitro.Also the liquid perfluorocarbons-filled nanocapsules can strongly enhance the ultrasound contrast in vitro,which might be taken as a kind of vascular ultrasound contrast agent and to get the basic experimental data for the later research.