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随着包膜微气泡材料和制备技术的发展,微气泡超声造影剂不仅用于超声成像诊断,而且在分子成像、药物传输及靶向治疗等多个领域得到广泛的研究与应用.实验制备了膜壳装载Fe3O4纳米颗粒、中心包裹氮气的聚合物微气泡造影剂,体外超声成像(US)显影实验发现该微气泡具有良好的超声图像增强作用.利用包膜微气泡在超声场作用下的振动模型研究其动力学行为发现,膜壳中包裹的Fe3O4纳米颗粒在一定浓度范围内能增加微气泡的膜壳散射截面,增强超声波的背向散射强度,从而显著增强超声图像的显影效果;当超过一定Fe3O4纳米颗粒浓度则会导致微气泡膜壳散射截面减小,从而降低超声图像增强效果.另一方面体外磁共振成像(MRI)显影实验证明,随着膜壳中Fe3O4纳米颗粒含量的增加,MRI增强效果亦增加.因此为了制备US和MRI双重显影增强的微气泡造影剂,控制磁性纳米颗粒在微气泡膜壳中的包裹量十分重要.
With the development of coated microbubbles and preparation techniques, microbubble ultrasound contrast agents are widely used in many fields, such as molecular imaging, drug delivery and targeted therapy, not only for the diagnosis of ultrasound imaging, but also for the experimental preparation Microencapsulated Fe3O4 nanoparticle loaded with nitrogen-containing polymeric micro-bubble contrast agent was studied by in-vitro ultrasound imaging (US) imaging experiments. The results show that this micro-bubble has a good ultrasonic image enhancing effect.Using the vibration of the micro- The dynamic behavior of the model was studied. It was found that the Fe3O4 nanoparticles encapsulated in the membrane shell can increase the scattering cross section of microbubbles and increase the backscattering intensity of the microbubble in a certain range of concentration, thus significantly enhancing the imaging performance of the ultrasound image. Certain Fe3O4 nanoparticle concentration will lead to the reduction of the scattering cross section of the microbubble membrane shell, thereby reducing the enhancement effect of ultrasound images.On the other hand, in vitro magnetic resonance imaging (MRI) imaging experiments show that with the increase of Fe3O4 nanoparticle content in the membrane shell, MRI enhancement also increased.Therefore, in order to prepare US and MRI dual development enhanced microbubble contrast agent, the control of magnetic nanoparticles The amount of pellets encapsulated in a microbubble shell is important.