Wang Yuchen, Li Hongchen, Meijlink Bram, Beurskens Robert, Johnson Benjamin R G, Kooiman Klazina
Biomedical Engineering, Department of Cardiology, Cardiovascular Institute, Erasmus MC, Rotterdam, 3015 GD, the Netherlands.
Biomedical Engineering, Department of Cardiology, Cardiovascular Institute, Erasmus MC, Rotterdam, 3015 GD, the Netherlands.
J Control Release. 2025 Aug 10;384:113867. doi: 10.1016/j.jconrel.2025.113867. Epub 2025 May 21.
Ultrasound insonification of microbubbles has been shown to increase vascular permeability to locally enhance drug delivery. For more effective and controllable therapeutic outcomes, uniform acoustic responses from microbubbles and a deeper understanding of the biophysical mechanisms of drug delivery are critical. In this study, we investigated the impact of monodisperse microbubble size and their dynamics on cellular responses and drug delivery outcomes in endothelial cells. Monodisperse microbubbles with radii of 1.5, 2.2, 2.7, and 2.9 μm were produced using a microfluidic flow-focusing device. Upon insonification (2 MHz, 220 kPa peak negative pressure, 10 cycles), the microbubble oscillation was captured in real-time at 10 million frames per second using ultra-high-speed imaging, while confocal microscopy was employed to observe cellular responses in both 2D and 3D. For the 65 microbubbles studied, the 2.2 μm microbubbles, i.e., corresponding to the resonant radius at 2 MHz ultrasound, exhibited the highest sonoporation rate (75 %), induced the largest membrane perforations (a median value of 78 μm) and highest intracellular drug uptake. The 1.5 μm microbubbles achieved a comparable sonoporation rate (73 %), yet with significantly smaller membrane perforations (a median value of 20 μm), lower intracellular drug uptake, and highest occurrence of transendothelial drug delivery pathways (64 %). Mechanistically, microbubble-generated shear stress was identified as the significant factor driving sonoporation, while normal stress did not show significance. In conclusion, our study highlights the importance of carefully selecting the microbubbles size to maximize microbubble-mediated drug delivery outcomes and facilitate safe translation of monodisperse microbubbles into clinical practice.
已证明超声对微泡进行声处理可增加血管通透性，从而局部增强药物递送。为了获得更有效且可控的治疗效果，微泡产生均匀的声学响应以及更深入地了解药物递送的生物物理机制至关重要。在本研究中，我们研究了单分散微泡大小及其动力学对内皮细胞中细胞反应和药物递送结果的影响。使用微流控流动聚焦装置制备了半径分别为1.5、2.2、2.7和2.9μm的单分散微泡。在进行声处理（2MHz，220kPa峰值负压，10个周期）时，使用超高速成像以每秒1000万帧的速度实时捕获微泡振荡，同时采用共聚焦显微镜在二维和三维中观察细胞反应。在所研究的65个微泡中，2.2μm的微泡，即对应于2MHz超声的共振半径，表现出最高的声孔形成率（75%），诱导出最大的膜穿孔（中位数为78μm）和最高的细胞内药物摄取。1.5μm的微泡实现了相当的声孔形成率（73%），但膜穿孔明显更小（中位数为20μm），细胞内药物摄取较低，并且跨内皮药物递送途径的发生率最高（64%）。从机制上讲，微泡产生的剪切应力被确定为驱动声孔形成的重要因素，而法向应力则不具有显著性。总之，我们的研究强调了仔细选择微泡大小对于最大化微泡介导的药物递送结果以及促进单分散微泡安全转化为临床实践的重要性。
