Ultrasound stimulated interactions of microbubbles and fibrin gels

暴露于超声波的气泡表现出丰富多样的行为，从径向振动到形状变化，再到伴随着光发射的剧烈坍塌。封装的微米尺寸的“微泡”被广泛用于生物医学超声，其中它们被用于实现血液灌注测量、执行分子成像以及增强治疗应用，诸如血凝块溶解。它们的动力学取决于各种因素，包括它们的大小以及超声的振幅和频率。附近边界的存在也会影响气泡的行为，使它们更难以振荡，并可能产生流体射流和不对称振荡。这是目前在与微循环内或邻近血管壁的微泡相关的条件下进行大量研究的主题。尚未研究血栓附近的基本气泡行为。这项研究的工作将研究超声如何与纤维蛋白凝胶附近的微泡相互作用，这些微泡捕获了血凝块的许多突出的机械方面。这将使用高速光学成像和声发射监测的组合来完成。这些结果将产生与理解超声、微泡和血栓之间相互作用相关的基本见解。这一基本信息最终对超声成像和超声增强血栓溶解的应用感兴趣。例如，振荡特性将决定如何进行成像以检查动脉粥样硬化和中风的各个方面。对于治疗应用，这将与理解药物如何转运到凝块中有关，因此可能有助于改善中风和心脏病发作的治疗。

Gas bubbles exposed to ultrasound exhibit a rich variety of behaviours ranging from radial vibrations, to shape changes, to violent collapses with light emissions. Encapsulated micron sized 'microbubbles' are widely employed in biomedical ultrasound where they are used to enable blood perfusion measurements, perform molecular imaging, and to enhance therapeutic applications, such as blood clot dissolution. Their dynamics are dependent upon a variety of factors including their size and the amplitude and frequency of the ultrasound. The presence of a nearby boundary will also affect the behaviour of bubbles, making them more difficult to oscillate, and possibly creating fluid jets and asymmetric oscillations. This is currently the subject of considerable investigation under conditions that are relevant to microbubbles contained within the microcirculation, or adjacent to blood vessel walls. Basic bubble behaviour adjacent to thrombus has not been investigated. The work in this study will examine how ultrasound interacts with microbubbles adjacent to fibrin gels, which capture many salient mechanical aspects of blood clots. This will be done using a combination of high speed optical imaging and acoustic emissions monitoring. The results will produce basic insights relevant to understanding into the interaction between ultrasound, microbubbles and thrombus. This basic information is of ultimately of interest for applications of ultrasound imaging and ultrasound potentiated dissolution of thrombus. For example, the oscillation characteristics will determine how imaging should be performed to examine aspects of atherosclerosis and stroke. For therapeutic applications this will be relevant to understanding how drug transport into the clots occurs and may therefore assist in improving therapies for stroke and heart attacks.