Evaluation of subharmonic emission from encapsulated microbubbles as an indicator for sonoporation of cell monolayers
Evaluation of subharmonic emission from encapsulated microbubbles as an indicator for sonoporation of cell monolayers
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评估封装微泡的次谐波发射作为细胞单层声孔作用的指标
DOI：
10.1109/ultsym.2009.5441709
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
S. Hahn
中科院分区：
文献类型：
--
作者：
K. Hensel;R. Haagen;G. Schmitz;A. Maghnouj;S. Hahn
声孔效应是超声诱导细胞膜的瞬时打开。附近的微泡（MB）的大规模振荡被认为是声孔的主要影响，而MB的破坏与较低的声孔效率和增加的细胞损伤相关。通过监测次谐波辐射，可以确定云中MB振荡的尺度。在本研究中，SW 480细胞在Opticell容器中生长，该容器装有含有SonoVue MB和碘化丙啶（PI）的生长培养基。将每个容器放置在水中，在3.3MHz下发射10个周期正弦脉冲串的单元件换能器的焦点处。峰值负压在75至750 kPa之间变化。散射信号由宽带换能器记录，以监测治疗期间的次谐波与基波比（SFR）。将荧光显微镜聚焦在治疗区域上，以在声激发期间和之后监测PI荧光。PI不能克服完整的细胞膜，并改变其荧光特性时，结合到细胞内液。如果细胞显示荧光强度的急剧上升和随后的下降，则认为细胞被声穿孔。如果荧光强度集中在细胞核处并上升至平台，则认为细胞永久染色。对于最大峰值负激励压力，观察到最大声穿孔（4.9%）和最大永久穿孔（2.8%）。通过永久染色细胞的数量校正声穿孔细胞的数量，对于520 kPa的振幅实现最佳声穿孔效率。SFR也是如此，在520 kPa时显著上升到最大值− 26.6 dB。声孔效率与SFR的关系表明，超声造影剂的次谐波发射是细胞单层声孔效率的一个指标。
Sonoporation is the ultrasound induced transient opening of cell membranes. Large scale oscillation of nearby microbubbles (MBs) is considered to be the primary effect in sonoporation whereas MB destruction correlates with lower sonoporation efficiency and increased cell damage. The scale of MB oscillation in a cloud can be determined by monitoring subharmonic emission. In this study, SW480 cells are grown in Opticell containers, which are filled with a growth medium containing SonoVue MBs and propidium iodide (PI). Each container is placed in water in the focus of a single element transducer emitting 10 cycles sine-bursts at 3.3 MHz. The peak negative pressure is varied from 75 to 750 kPa. Scattered signals are recorded by a broadband transducer to monitor subharmonic-to-fundamental ratio (SFR) during therapy. A fluorescence microscope is focused on the therapy region to monitor PI fluorescence during and after acoustic excitation. PI cannot overcome intact cell membranes and changes its fluorescence properties when bound to intracellular fluid. A cell is considered sonoporated, if it reveals a sharp rise of fluorescence intensity and a subsequent decrease. A cell is considered permanently stained, if fluorescence intensity is concentrated at the cell nucleus and rises to a plateau. For maximum peak negative excitation pressure, maximum sonoporation (4.9%) and maximum permanent poration (2.8%) is observed. Correcting the number of sonoporated cells by the number of permanently stained cells, best sonoporation efficiency is achieved for the amplitude of 520 kPa. The same holds for the SFR, which significantly rises to a maximum of −26,6 dB at 520 kPa, too. The relationship of sonoporation efficiency and SFR reveals that subharmonic emission from ultrasound contrast agent is an indicator for sonoporation efficiency of cell monolayers.