Ultrasound stimulated interactions of microbubbles and fibrin gels

暴露在超声波下的气泡表现出丰富多样的行为，从径向振动到形状变化，再到伴随光发射的剧烈塌陷。封装的微米大小的“微泡”广泛应用于生物医学超声中，用于进行血液灌注测量、执行分子成像以及增强治疗应用，例如血凝块溶解。它们的动态取决于多种因素，包括它们的大小以及超声波的幅度和频率。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。目前，在与微循环内或邻近血管壁的微泡相关的条件下，这是大量研究的主题。尚未研究邻近血栓的基本气泡行为。这项研究的工作将检查超声波如何与纤维蛋白凝胶附近的微泡相互作用，纤维蛋白凝胶捕获血栓的许多显着机械方面。这将通过结合高速光学成像和声发射监测来完成。结果将产生与理解超声波、微泡和血栓之间相互作用相关的基本见解。这一基本信息对于超声成像和超声强化血栓溶解的应用最终具有重要意义。例如，振荡特性将决定如何进行成像来检查动脉粥样硬化和中风的各个方面。对于治疗应用来说，这将有助于了解药物如何转运到血栓中，因此可能有助于改善中风和心脏病的治疗。

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.