中文摘要：

目的制备一种胰腺癌靶向的纳米级超声造影剂并评价其体外靶向性效果。方法用聚乳酸-羟基乙酸共聚物（PLGA）、N-羟基琥珀酰亚胺（NHS）、聚乙二醇（PEG）合成高分子聚合物PLGA-PEG-NHS并利用核磁共振氢谱检测;用PLGA-PEG-NHS和全氟溴辛烷（PFOB）以乳化挥发法制备包裹PFOB的PLGA纳米造影剂,然后连接Hedgehog抗体。透射电镜观察纳米造影剂的形态,动态光散射法测定其粒径、电位;气相色谱-质谱法测定纳米造影剂的包封率及载药量;透析法测定纳米造影剂的体外释放特性。用添加了纳米造影剂的培养液培养人胰腺癌细胞株SW1990和CFPAC-1,利用荧光显微镜和流式细胞仪定性和定量验证纳米造影剂的体外靶向能力。结果所制得的胰腺癌靶向纳米超声造影剂平均粒径为198.9nm,Zeta电位为-31.8mV,包封率（63.7±3.9）%,载药量（14.3±0.9）%,48h释药量为85.3%;体外细胞实验显示靶向造影剂与高表达Hedgehog抗原的SW1990细胞大量结合,而与不表达Hedgehog抗原的CFPAC-1细胞未见特异性结合。结论通过乳化挥发法制备的胰腺癌靶向纳米超声造影剂各项表征符合要求,并能特异性靶向Hedgehog高表达的胰腺癌细胞,有望成为胰腺癌诊断的超声造影剂。

英文摘要：

Objective To prepare a pancreatic cancer-targeted nano-scale ultrasound contrast agent（T-UCA）and to evaluate its in vitro targeting effect.Methods PLGA-PEG-NHS was synthesized with poly（lactic-co-glycolic acid）（PLGA）,N-hydroxysuccinimide（NHS）and polyethylene glycol（PEG）.The construction of PLGA-PEG-NHS was characterized by1 H-NMR.Perfluoroctyl bromide（PFOB）-loaded PLGA nanoparticle contrast agent was prepared using emulsion evaporation technique with PLGA-PEG-NHS and PFOB,and the products were further conjugated with Hedgehog antibody.The morphology of T-UCA were characterized by transmission electron microscopy,and the size distribution and Zeta potential of T-UCA were characterized by dynamic light scattering method.Furthermore,the drug entrapment efficiency and loading capacity of T-UCA were determined by GC-MS,and the release rate of T-UCAin vitro was examined by dialysis method.Finally,the in vitro targeting performance was quantitatively verified by fluorescence microscopy and flow cytometry with human pancreatic cancer lines SW1990 and CFPAC-1.Results The average diameter and the Zeta potential of T-UCA were198.9nm and-31.8mV,respectively.Moreover,the encapsulation efficiency and drug loading of T-UCA was（63.7±3.9）%and（14.3 ± 0.9）%,respectively.Nearly 85.3% liquid perfluorocarbon was released from the T-UCA within 48 h.In vitro cell experiments showed that the targeted contrast agent could bind to SW1990 cells which had high expression of Hedgehog antigen,while not to the CFPAC-1cells without expression of Hedgehog antigen.Conclusion The emulsion evaporation technique can be used to prepare T-UCA with desirable characteristics,and the prepared T-UCA can specifically target the pancreatic cancer cells with high expression of Hedgehog,making it a promising pancreatic cancer-targeted nanosacle ultrasound contrast agent.