相变型液态氟碳纳米粒造影剂的制备及相变超声显影研究

Preparation of a phase-change perfluorocarbon nanoparticles contrast agent and its phase transformation study for enhancing ultrasonography

目的制备一种相变型液态氟碳纳米粒超声造影剂(PC-PNPCA),研究其在体外相变及增强超声显影作用的能力。方法首先采用双步乳化法制备出以脂质为包壳、液态氟碳PFH为内核的纳米粒超声造影剂,检测该造影剂的粒径、电荷。然后分别用升高温度、低功率治疗超声及高强度聚焦超声辐照三种方法来激发纳米粒相变,用显微镜观察相变后产生的微泡,使用诊断超声仪在造影模式下观察造影剂相变后增强超声显影的情况。结果成功制备出脂质包裹PFH的PC-PNPCA,PC-PNPCA平均粒径为(206.87±21.29)nm。当温度升高至70℃以上,低功率治疗超声辐照10 s或高强度聚焦超声辐照2 s后,乳液内的纳米粒均可发生相变产生微泡,且能促进超声显影。结论制备的PC-PNPCA能在一定条件下发生相变并增强超声显影,为超声分子影像学提供了新型、可靠的研究平台。

Objective To prepare a phase-change perfluorocarbon nanoparticles contrast agent （PC-PNPCA） for uhrasonography and study on its ability of phase transformation thus enhancing ultrasonography in vitro.Methods Firstly,the nanoparticles contrast agent with lipids shell and perfluorohexan kernel was prepared by a two-step emulsification.The particles size and charge of the nanoparticles were detected.Then temperature rise, irradiation of low-power theraputic uhrasound and high- intensity focused ultrasound were applied respectively to stimulate the phase transformation of the nanoparticles.The microbubbles generated from the PC-PNPCA were observed with optical microscope.The enhancing of uhrasonography by the PC-PNPCA was observed with the diagnostic ultrasound in contrast mode.Results The PC-PNPCA emulsion for ultrasonography with lipids wrapped perfluorohexan nanoparticles was successfully prepared.The mean particles size was about （206.87 ± 21.29） nm.When the temperature risen to 70℃ above,or 10 s of low-power ultrasonic irradiation or 2 s of high intensity focused ultrasound irradiation,the nanoparticles within the emulsions would undergo phase transformations and produce microbubbles,which could enhancing uhrasonography of the diagnostic ultrasound.Conclusion The prepared PC-PNPCA can produce microbubbles and enhance ultraonography after phase transformation under certain conditions.Therefore,a novel,reliable research platform for ultrasound molecular imaging was provided.