Focused Ultrasound Controlled Cavitation Bubble Collapse and Promotion of Sonoporation Effect

本文用频率为1MHz的超声波从两种类型的超声探头（平边界和弯曲边界）照射，研究了Sonazoid破坏与由此产生的空化现象之间的关系。超声辐照后100 ms内，Sonazoid微泡被迅速破坏，存活数量减少到原来的一半。微泡碎片在空化过程中起空化核的作用，大量的空化泡从空化核中生长出来。在气泡溃灭的短时间内，产生了液体微射流和冲击波。由这些短期现象之一产生的冲击压力似乎是声致穿孔的重要原因，声致穿孔可以在细胞膜上瞬时形成细孔。

The relation between Sonazoid destruction and the resultant cavitation phenomena has been investigated by employing ultrasound waves with the frequency of 1 MHz which were irradiated from two types of US probes with a flat boundary as well as a curved boundary. It was found that Sonazoid microbubbles were rapidly destroyed and the survival number was reduced to half the original number within 100 ms after ultrasound irradiation. The debris of microbubbles played a role of cavitation nuclei from which a large number of cavitation bubbles grew. A liquid micro-jet and a shock wave occurred during the short period of the bubble collapse. An impact pressure resulting from one of these short term phenomena seems to be an important cause of sonoporation which could make a fine hole in the cell membrane transiently.