Engineering Microbubbles for Enhanced Non-linear Response: Modelling and Experimental Studies

气泡对声激励的非线性响应是生物医学和工程科学中的一个重要现象。例如，在医学超声成像中，微泡由于其非线性散射超声的能力而特别用作造影剂。然而，增加非线性度通常需要增加激励幅度，这也可能导致剧烈行为，例如惯性空化和气泡破碎;这可能是非常不希望的效果，特别是在生物医学应用中。本提案中描述的工作的目的是调查我们最近的初步研究结果，该研究表明，通过在微泡表面上沉积纳米颗粒，其声学响应的非线性特性可以在低激励振幅下显着增加。我们建议开发一个理论模型来预测这种行为，并检查对气泡稳定性的影响，并进行系统的实验研究纳米颗粒的大小，形状和浓度对微泡的稳定性和声学响应的影响，以验证理论工作。一个成功的结果将导致微泡剂的开发具有改善的功效和可预测性，用于成像和治疗应用，这将为制药和医疗保健行业，仪器制造商以及最终的临床医生和患者提供显着的好处。

The non-linear response of gas bubbles to acoustic excitation is an important phenomenon in both the biomedical and engineering sciences. In medical ultrasound imaging, for example, microbubbles are particularly useful as contrast agents on account of their ability to scatter ultrasound non-linearly. Increasing the degree of non-linearity, however, normally requires an increase in the amplitude of excitation and this may also result in violent behaviour such as inertial cavitation and bubble fragmentation; effects which may be highly undesirable, especially in biomedical applications. The aim of the work described in this proposal is to investigate the findings from our recent preliminary study which showed that by depositing nanoparticles on the surface of a microbubble, the non-linear character of its acoustic response can be increased significantly at low excitation amplitudes. We propose to develop a theoretical model to predict this behaviour and to examine the effect upon bubble stability; and to carry out systematic experimental investigations of the influence of nanoparticle size, shape and concentration upon the stability and acoustic response of microbubbles in order to verify the theoretical work. A successful outcome will lead to the development of microbubble agents with improved efficacy and predictability, for both imaging and therapeutic applications, that will offer significant benefits to the pharmaceutical and healthcare industries, instrumentation manufacturers and ultimately clinicians and patients.