Cavitation microstreaming and stress fields created by microbubbles
Cavitation microstreaming and stress fields created by microbubbles
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DOI：
10.1016/j.ultras.2009.10.002
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发表时间：
2010-02-01
期刊：
影响因子：
4.2
通讯作者：
Zhu, Yonggang
中科院分区：
文献类型：
--
作者：
Collis, James;Manasseh, Richard;Zhu, Yonggang
空化微流在超声驱动的微泡的治疗作用中起着重要作用，如超声疏通和超声溶栓现象。介绍了显微粒子图像测速实验。结果表明，当微泡在表面时，周围可能有许多不同的微流模式，尽管微泡的体积比临床上使用的要大得多。每种模式与气泡的特定振荡模式相关联，并且通过改变声音频率来实现模式之间的改变。每种微流模式还在壁上气泡附近产生不同的剪应力和拉伸/压缩分布。对Micro-PIV结果的分析还表明，超声驱动的围绕气泡的微流是将治疗剂混合到周围血液中以及帮助分子通过细胞膜进行声波疏松输送的可行机制。气泡周围的模式显示出显著的差异，这表明声波打开可能在细胞表面的不同区域被增强或被抑制。因此，交替使用这些模式可能导致改进的声学手术和声学溶栓。基于驱动频率的微流模式的清晰和可重现的描绘使得基于频率的模式交替成为临床上不太可取的做法的一种可行的替代方案，即增加声压以达到同等的声孔或声溶栓效果。表面发散被认为是一种与声发射相关的测量方法。皇冠版权所有(C)2009由爱思唯尔出版。保留所有权利。
Cavitation microstreaming plays a role in the therapeutic action of microbubbles driven by ultrasound, such as the sonoporative and sonothrombolytic phenomena. Microscopic particle-image velocimetry experiments are presented. Results show that many different microstreaming patterns are possible around a microbubble when it is on a surface, albeit for microbubbles much larger than used in clinical practice. Each pattern is associated with a particular oscillation mode of the bubble, and changing between patterns is achieved by changing the sound frequency. Each microstreaming pattern also generates different shear stress and stretch/compression distributions in the vicinity of a bubble on a wall. Analysis of the micro-PIV results also shows that ultrasound-driven microstreaming flows around bubbles are feasible mechanisms for mixing therapeutic agents into the surrounding blood, as well as assisting sonoporative delivery of molecules across cell membranes. Patterns show significant variations around the bubble, suggesting sonoporation may be either enhanced or inhibited in different zones across a cellular surface. Thus, alternating the patterns may result in improved sonoporation and sonothrombolysis. The clear and reproducible delineation of microstreaming patterns based on driving frequency makes frequency-based pattern alternation a feasible alternative to the clinically less desirable practice of increasing sound pressure for equivalent sonoporative or sonothrombolytic effect. Surface divergence is proposed as a measure relevant to sonoporation. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.