链霉亲和素化载紫杉醇相变型PLGA纳米粒的制备及体外超声显影

Preparation of streptavidin-coated and paclitaxel-loaded phase-shifting PLGA nanoparticles and ultrasound imaging in vitro

目的制备链霉亲和素化载紫杉醇相变型PLGA纳米粒(PTX-PLGA-SA/PFPs),并观察其体外低强度聚焦超声(LIFU)致相变后超声增强显影特性。方法采用单乳化法(O/W)制备载紫杉醇相变型PLGA纳米粒,高效液相色谱法检测紫杉醇包封率;碳二亚胺法连接链霉亲和素(SA),共聚焦激光显微镜观察二者连接情况,流式细胞术检测二者链接率;体外LIFU致相变观察超声增强显影情况。结果制备的纳米粒粒径为(322.2±85.6)nm,表面电位(-5.66±3.46)mV。紫杉醇的包封率及载药量分别为(71.56±6.51)%、(6.57±0.61)%,与链霉亲和素的连接率为(97.16±1.20)%。LIFU功率7.5 W作用3min时可明显增强该纳米粒在体外的B-mode及造影模式下的超声显影。结论成功制备了PTX-PLGA-SA/PFPs纳米粒,其紫杉醇包封率高、链霉亲和素连接率高,体外声致相变后可显著增强超声显影。

Objective To prepare a paclitaxel-loaded and streptavidin-coated phase-shifting PLGA nanoparticle as an agents for tumor ultrasound molecular imaging and treatment, and to explore the condition of low intensity focused ultra- sound （LIFU） inducing phase transition of the nanoparticles to enhance the ultrasound imaging. Methods The single emulsion method （O/W） was used to prepare the paclitaxel-loaded nanoparticles （NBs）. The NBs size and zeta potential were detected by Melvin size analyzer. The streptavidin （SA） was covalently linked on the NBs through carbodiimide meth- od, and the connection rate was detected by flow cytometry （FCM）. The encapsulation efficiency of paclitaxel capsuled in NBs was determined by high-performance liquid chromatography （HPLC）. Different intensities of LIFU were applied to optimize the condition of phase transition of NBs. Results The size of NBs was （322.2±85.6）nm, and zeta potential was （-5.66±3.46）mV. The SA was successfully conjugated to the NBs, and the connection rate was （97.16±1.20）%. The encapsulation efficiency and drug loading efficiency of paclitaxel were （71.56±6.51） % and （6.5±0.61）%, respectively. When the the LIFU powers was 7.5 W working for 3 min, the NBs occurring phase transition could significantly enhance the ultrasound imaging in both B-mode and contrast enhance mode. Conclusion The paclitaxel-loaded and streptavidin-coated phase-shifting PLGA nanopartide is successfully prepared. With high encapsulation efficiency of paclitaxel and high connection rate of SA, the NBs can be used to significantly enhance ultrasound imaging in vitro after phase transition triggered by LIFU.