靶向相变型载药纳米造影剂的制备及其基本性能和显像特性检测

Preparation of targeted and phase-shifted nano-scaled contrast agentsloaded with drug and detection of the basic performance

目的制备一种叶酸靶向相变型载羟基喜树碱(HCPT)的纳米粒(FA-HCPT-Fe_(3)O_(4)-PFP NDs),检测其基本性能和多模态显像特性。方法采用旋转蒸发-超声法制备FA-HCPT-Fe_(3)O_(4)-PFP NDs。于制备后不同时间点使用电子显微镜测定纳米粒粒径以检测其稳定性;将纳米粒乳液加热后置于显微镜下观察其相变特性,高效液相色谱法检测纳米粒内药物(HCPT)的载药量。检测观察纳米粒对富含叶酸受体的SKOV3肿瘤细胞的寻靶能力。对不同浓度纳米粒制备成的凝胶块进行光声成像及MRI;使用低强度聚焦超声(LIFU)辐照纳米粒乳液后行超声成像,分别验证其增强光声、MRI及超声成像的能力。结果制备的FA-HCPT-Fe_(3)O_(4)-PFP NDs性质稳定,HCPT载药量为(8.33±0.57)%,包封率为(60.51±2.33)%,加热后可发生液气相变。体外寻靶实验证实该纳米粒对富含叶酸受体的SKOV3肿瘤细胞局部有良好的靶向性。体外多模态显像增强实验结果表明该纳米粒可以明显增强超声、光声及MRI的显影能力。结论本实验所制备的FA-HCPT-Fe_(3)O_(4)-PFP NDs具备多模态造影剂的功能,是一种极具潜力的分子探针。

Objective To prepare phase-shifted folate-modified and HCPT-loaded nanodroplets(FA-HCPT-Fe_(3)O_(4)-PFP NDs),and to investigate the properties and multimodality imaging in vitro.Methods The FA-HCPT-Fe_(3)O_(4)-PFP NDs were prepared through the rotary evaporation and sonication process.The size and the stability of FA-HCPT-Fe_(3)O_(4)-PFP NDs were detected at different time point after preparation.The phase transition characteristic of the nanodroplets was detected.Drug loading was determined with reverse-phase high-performance liquid chromatographic system.Targeting efficiency of FA-HCPTFe_(3)O_(4)-PFP NDs was validated with cell experiment.Photoacoustic and magnetic resonance imaging were performed on the gel blocks prepared by different concentrations of nanoparticles.Ultrasonic imaging was performed after irradiation of the nanoparticle emulsion with LIFU.The above experiments were used to verify the ability of nanoparticles to enhance photoacoustic imaging,MRI and ultrasound imaging.Results The prepared nanodroplets were stable,the drug loading was(8.33±0.57)%,and encapsulation efficiency was(60.51±2.33)%.Phase-transition was observed of FA-HCPT-Fe_(3)O_(4)-PFP NDs with elevated temperature.Targeting experiments in vitro confirmed that the nanoparticles had good targeting ability to SKOV3 tumor cells rich in folate receptors.FA-HCPT-Fe_(3)O_(4)-PFP NDs nanoemulsions showed obvious photoacoustic signal,MRI signal and ultrasound signal in vitro.Conclusion FA-HCPT-Fe_(3)O_(4)-PFP NDs,the successfully fabricated multimodal contrast agent is a molecular probe with great potential.