Sonodynamic therapy (SDT) is an emerging antibacterial therapy. This work selected hematoporphyrin monomethyl ether (HMME) as the sonosensitizer, and studied the enhanced inhibition effect of Escherichia coli and biofilm by microbubble-mediated cavitation in SDT. Firstly, the influence of microbubble-mediated cavitation effect on different concentrations of HMME (10 µg/ml, 30 µg/ml, 50 µg/ml) was studied. Using 1,3-diphenylisobenzofuran (DPBF) as an indicator, the effect of microbubble-mediated cavitation on the production of reactive oxygen species (ROS) was studied by absorption spectroscopy. Secondly, using agar medium, laser confocal microscopy and scanning electron microscopy, the effect of microbubble-mediated cavitation on the activity and morphology of bacteria was studied. Finally, the inhibitory effect of cavitation combined with SDT on biofilm was evaluated by laser confocal microscopy. The research results indicate that: (1) Microbubble-mediated ultrasound cavitation can significantly increase cavitation intensity and production of ROS. (2) Microbubble-mediated acoustic cavitation can alter the morphological structure of bacteria. (3) It can significantly enhance the inhibition of SDT on the activity of Escherichia coli and its biofilm. Compared with the control group, the addition of microbubbles resulted in an increase in the number of dead bacteria by 61.7 %, 71.6 %, and 76.2 %, respectively. The fluorescence intensity of the biofilm decreased by 27.1 %, 80.3 %, and 98.2 %, respectively. On the basis of adding microbubbles to ensure antibacterial and biofilm inhibition effects, this work studied the influence of cavitation effect in SDT on bacterial structure, providing a foundation for further revealing the intrinsic mechanism of SDT.

中文翻译：

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微泡介导的声动力疗法中增强空化剂量和活性氧产生，抑制大肠杆菌和生物膜


声动力疗法（SDT）是一种新兴的抗菌疗法。本工作选择血卟啉单甲醚（HMME）作为声敏剂，研究SDT中微泡介导的空化作用对大肠杆菌和生物膜的增强抑制作用。首先，研究了微泡介导的空化效应对不同浓度 HMME（10 µg/ml、30 µg/ml、50 µg/ml）的影响。以1,3-二苯基异苯并呋喃（DPBF）为指示剂，通过吸收光谱研究了微泡介导的空化对活性氧（ROS）产生的影响。其次，利用琼脂培养基、激光共聚焦显微镜和扫描电镜，研究了微泡介导的空化对细菌活性和形态的影响。最后，通过激光共聚焦显微镜评估空化结合SDT对生物膜的抑制效果。研究结果表明：（1）微泡介导的超声空化可以显着增加空化强度和ROS的产生。 (2)微泡介导的声空化可以改变细菌的形态结构。 (3)能显着增强SDT对大肠杆菌及其生物膜活性的抑制作用。与对照组相比，添加微泡导致死亡细菌数量分别增加 61.7%、71.6% 和 76.2%。生物膜的荧光强度分别降低了 27.1%、80.3% 和 98.2%。本工作在添加微泡保证抗菌和生物膜抑制效果的基础上，研究了SDT中的空化效应对细菌结构的影响，为进一步揭示SDT的内在机制奠定了基础。