El Ghamrawy Ahmed, de Comtes Florentina, Koruk Hasan, Mohammed Ali, Jones Julian R, Choi James J
Noninvasive Surgery and Biopsy Laboratory, Department of Bioengineering, Imperial College London, London, United Kingdom.
Noninvasive Surgery and Biopsy Laboratory, Department of Bioengineering, Imperial College London, London, United Kingdom; Mechanical Engineering Department, MEF University, Istanbul, Turkey.
Ultrasound Med Biol. 2019 Jan;45(1):208-217. doi: 10.1016/j.ultrasmedbio.2018.08.026. Epub 2018 Oct 15.
We demonstrated that sound can push fluid through a tissue-mimicking material. Although acoustic streaming in tissue has been proposed as a mechanism for biomedical ultrasound applications, such as neuromodulation and enhanced drug penetration, streaming in tissue or acoustic phantoms has not been directly observed. We developed a material that mimics the porous structure of tissue and used a dye and a video camera to track fluid movement. When applied above an acoustic intensity threshold, a continuous focused ultrasound beam (spatial peak time average intensity: 238 W/cm, centre frequency: 5 MHz) was found to push the dye axially, that is, in the direction of wave propagation and in the radial direction. Dye clearance increased with ultrasound intensity and was modelled using an adapted version of Eckart's acoustic streaming velocity equation. No microstructural changes were observed in the sonicated region when assessed using scanning electron microscopy. Our study indicates that acoustic streaming can occur in soft porous materials and provides a mechanistic basis for future use of streaming for therapeutic or diagnostic purposes.
我们证明了声音能够推动流体通过一种仿组织材料。尽管组织中的声流已被提出作为生物医学超声应用（如神经调节和增强药物渗透）的一种机制，但尚未在组织或声学体模中直接观察到声流。我们开发了一种模仿组织多孔结构的材料，并使用一种染料和一台摄像机来追踪流体运动。当施加高于声强阈值的超声时，发现连续聚焦超声束（空间峰值时间平均强度：238 W/cm²，中心频率：5 MHz）会沿轴向推动染料，即沿波传播方向以及径向推动。染料清除率随超声强度增加，并使用埃卡特声流速度方程的一个改编版本进行建模。使用扫描电子显微镜评估时，在超声处理区域未观察到微观结构变化。我们的研究表明，声流可以在柔软多孔材料中发生，并为未来将声流用于治疗或诊断目的提供了一个机制基础。
