Haghi Hossein, Kolios Michael C
Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario, Canada; Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between St. Michael's Hospital and Toronto Metropolitan University, 209 Victoria St, Toronto, Ontario, Canada.
Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario, Canada; Institute for Biomedical Engineering, Science and Technology (iBEST), a partnership between St. Michael's Hospital and Toronto Metropolitan University, 209 Victoria St, Toronto, Ontario, Canada.
Ultrason Sonochem. 2024 Mar;104:106831. doi: 10.1016/j.ultsonch.2024.106831. Epub 2024 Feb 28.
Ultrasonically excited microbubbles (MBs) have numerous applications in various fields, such as drug delivery, and imaging. Ultrasonically excited MBs are known to be nonlinear oscillators that generate secondary acoustic emissions in the media when excited by a primary ultrasound wave. The propagation of acoustic waves in the liquid is limited to the speed of sound, resulting in each MB receiving the primary and secondary waves at different times depending on their distance from the ultrasound source and the distance between MBs. These delays are referred to as primary and secondary delays, respectively. A previous study demonstrated that the inclusion of secondary delays in a model describing the interactions between MBs exposed to ultrasound results in an increase in the linear resonance frequency of MBs as they approach each other. This work investigates the impact of various MB properties on the change in linear resonance frequency resulting from changes in inter-bubble distances. The effects of shell properties, including the initial surface tension, surface dilatational viscosity of the shell monolayer, elastic compression modulus of the shell, and the initial radius of the MBs, are examined. MB size is a significant factor influencing the rate of linear resonance frequency increase with increasing concentration. Moreover, it is found that the shell properties of MBs play a negligible role in the rate of change in linear resonance frequency of MBs as the inter-bubble distances change.The findings of this study have implications for various applications of MBs in the biomedical field. By understanding the impact of inter-bubble distances and shell properties on the linear resonance frequency of MBs, the utilization of MBs in applications reliant on their resonant behavior can be optimized.
超声激发微泡（MBs）在药物递送和成像等各个领域有众多应用。已知超声激发的微泡是非线性振荡器，当被初级超声波激发时会在介质中产生二次声发射。液体中声波的传播速度限于声速，这导致每个微泡根据其与超声源的距离以及微泡之间的距离在不同时间接收初级波和次级波。这些延迟分别称为初级延迟和次级延迟。先前的一项研究表明，在描述暴露于超声的微泡之间相互作用的模型中纳入次级延迟会导致微泡彼此靠近时其线性共振频率增加。这项工作研究了各种微泡特性对因泡间距离变化而导致的线性共振频率变化的影响。研究了壳层特性的影响，包括初始表面张力、壳层单分子层的表面膨胀粘度、壳层的弹性压缩模量以及微泡的初始半径。微泡尺寸是影响线性共振频率随浓度增加而增加速率的一个重要因素。此外，发现随着泡间距离变化，微泡的壳层特性对微泡线性共振频率的变化速率影响可忽略不计。本研究的结果对微泡在生物医学领域的各种应用具有启示意义。通过了解泡间距离和壳层特性对微泡线性共振频率的影响，可以优化微泡在依赖其共振行为的应用中的利用。
