Faculty of Engineering and Physical Sciences, University of Southampton, University Road, Southampton SO17 1BJ, United Kingdom.
Department of Engineering Science, University of Oxford, Old Road, Headington, Oxford OX3 7LD, U.K.
ACS Biomater Sci Eng. 2023 Oct 9;9(10):5912-5923. doi: 10.1021/acsbiomaterials.3c00757. Epub 2023 Sep 25.
Microbubbles utilize high-frequency oscillations under ultrasound stimulation to induce a range of therapeutic effects in cells, often through mechanical stimulation and permeabilization of cells. One of the largest challenges remaining in the field is the characterization of interactions between cells and microbubbles at therapeutically relevant frequencies. Technical limitations, such as employing sufficient frame rates and obtaining sufficient image resolution, restrict the quantification of the cell's mechanical response to oscillating microbubbles. Here, a novel methodology was developed to address many of these limitations and improve the image resolution of cell-microbubble interactions at high frame rates. A compact acoustic device was designed to house cells and microbubbles as well as a therapeutically relevant acoustic field while being compatible with a Shimadzu HPV-X camera. Cell viability tests confirmed the successful culture and proliferation of cells, and the attachment of DSPC- and cationic DSEPC-microbubbles to osteosarcoma cells was quantified. Microbubble oscillation was observed within the device at a frame rate of 5 million FPS, confirming suitable acoustic field generation and ultra high-speed image capture. High spatial resolution in these images revealed observable deformation in cells following microbubble oscillation and supported the first use of digital image correlation for strain quantification in a single cell. The novel acoustic device provided a simple, effective method for improving the spatial resolution of cell-microbubble interaction images, presenting the opportunity to develop an understanding of the mechanisms driving the therapeutic effects of oscillating microbubbles upon ultrasound exposure.
微泡利用超声刺激下的高频振荡，通过对细胞的机械刺激和渗透作用，引发一系列治疗效果。该领域仍面临的最大挑战之一是在治疗相关频率下对细胞与微泡之间的相互作用进行特征描述。技术限制，如采用足够的帧率和获得足够的图像分辨率，限制了对振荡微泡的细胞机械响应的定量。在这里，开发了一种新的方法来解决许多这些限制，并提高高帧率下细胞-微泡相互作用的图像分辨率。设计了一个紧凑的声学装置，以容纳细胞和微泡以及治疗相关的声场，同时与岛津 HPV-X 相机兼容。细胞活力测试证实了细胞的成功培养和增殖，以及 DSPC 和阳离子 DSEPC 微泡附着在骨肉瘤细胞上的定量。在 500 万帧/秒的帧率下观察到装置内的微泡振荡，证实了合适的声场产生和超高速图像捕获。这些图像中的高空间分辨率揭示了微泡振荡后细胞的可观察变形，并支持首次将数字图像相关用于单细胞中的应变定量。新型声学装置为提高细胞-微泡相互作用图像的空间分辨率提供了一种简单有效的方法，为进一步开发理解超声作用下振荡微泡的治疗效果的机制提供了机会。
