Ultrasound stimulated interactions of microbubbles and fibrin gels

点击翻译按钮获取中文摘要

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.