载超顺磁性氧化铁高分子液态氟碳纳米粒的制备及体外显像

Preparation and imaging in vitro for perfluorohexane-encapsulated superparamagnetic poly(lactic-co-glycolic acid)-iron oxide multifunctional ultrasound contrast agents

目的制备一种能同时用于超声造影及MR成像的多模态造影剂,观察其体外成像效果。方法采用双乳化法合成载超顺磁性氧化铁(SPIO)纳米颗粒及全氟己烷(PFH)的高分子微球(s-PFH/PLGA),检测其一般特性及光声信号。对不同浓度的s-PFH/PLGA水囊模型进行超声显影,以JC200聚焦超声肿瘤治疗系统辐照后观察回声强度变化;对不同铁含量的s-PFH/PLGA进行MR成像。结果透射电镜下s-PFH/PLGA呈球形,SPIO颗粒均匀分布在外壳上,平均粒径(738.9±158.4)nm,平均电位(-15.9±6.9)mV,并检测到明显光声信号。体外超声显像中s-PFH/PLGA呈点状高回声,HIFU辐照后回声强度增强。s-PFH/PLGA在T2WI中呈负增强显像;随着铁含量增高,MRI信号呈降低趋势。结论成功制备的载SPIO及PFH多模态造影剂具有体外超声、MR显影功能。

Objective To prepare multi-mode contrast agent, and to investigate its effect for ultrasound and MR imaging in vitro. Methods Double emulsion method was used to prepare perfluorohexane-encapsulated superparamagnetic poly [lactic-co-glycolicacid, PLGA]-iron oxide （s-PFH/PLGA）, and its morphology, size, Fe3O4 loading capacity and photoac- coustic detection were assessed. Then, the prepared s-PFH/PLGA microcapsules were applied with different concentrations to perform ultrasound imaging, and the echogenicity was assessed post irradiation using JC200 focused ultrasound tumor therapy system. Then s-PFH/PLGA microcapsules were also applied to perform MR imaging in vitro, and the signal intensity was calculated. Results The s-PFH/PLGA microcapsules were observed with regular spherical morphology, the average size was （738. 9 ±158. 4）nm, average electric potential was （- 15.9 ± 6.9）mV, and photoaccoustie signal could be detected. In vitro, s-PFH/PLGA microcapsules showed hyper echogenicity in US imaging which increased after HIFU irra- diation. In MRI, s-PFH/PLGA negatively enhanced on T2WI, and the signal intensity decreased with the increase of iron content. Conclusion The prepared s-PFH/PLGA microcapsules can successfully act as contrast agent of ultrasound and MR imaging in vitro.