叶酸受体靶向高分子相变超声造影剂的制备及体外寻靶实验研究

目的制备一种叶酸受体靶向的相变超声造影剂,观察其体外细胞靶向效果及超声显影情况。方法采用单乳化法制备包裹液态氟碳的高分子纳米微球,通过碳二亚胺法连接叶酸配体制备叶酸受体靶向的相变超声造影剂,以人卵巢癌SKOV3细胞验证其体外细胞靶向性能,以高强度聚焦超声(HIFU)体外辐照实验观察其超声显影情况。结果所制备叶酸受体靶向高分子相变超声造影剂平均粒径为(229.13±13.46)nm,体外细胞寻靶实验显示靶向造影剂与SKOV3细胞大量结合,而普通造影剂组与游离叶酸干预组未见明显特异性结合。造影剂溶液经一定功率HIFU辐照后,超声显影效果较辐照前明显增强。结论成功制备了叶酸受体靶向包裹液态氟碳的高分子造影剂,对高表达叶酸受体的SKOV3细胞具有良好靶向性,并具备HIFU辐照后增强超声显影的特性,有望成为卵巢癌靶向显影与治疗的理想分子探针。

Preparation of folate receptor-targeted, phase-shift ultrasound contrast agent and its targeting effect in vitro

Objective To prepare a new type of ultrasound contrast agent, folate receptor-targeted phase-shift microcapsules of liquid perfluorocarbon, and to investigate its targeting and imaging performance in vitro. Methods Polymeric microcapsules of liquid perfluorocarbon were prepared by using single emulsion technique and conjugated with folate by carbodiimide technique. The targeting performance was verified by being incubated with human SKOV3 cells lines in vitro. After irradiation by high intensity focused ultrasound (HIFU), the phase-shift characteristic and contrast enhanced effect for ultrasound were observed. Results The new contrast agent appeared as milky suspension with a mean size of (229.13±13.46) nm. In the folate receptor-targeted group, a number of microcapsules conjugated to SKOV3 cells tightly, while no specific binding was found in the non-targeted group and the free folic acid intervention group. After HIFU irradiation, the contrast agent remarkably enhanced ultrasound imaging in vitro. Conclusion The folic acid conjugated polymeric microcapsules of liquid perfluorocarbon can targeted to SKOV3 cells specifically and effectively in vitro, which will hopefully become an ultrasound contrast agent and have the potential of ideal molecular probe for the targeted imaging and treatment of ovarian carcinoma.