CYTOMECHANICAL PERTURBATIONS DURING LOW-INTENSITY ULTRASOUND PULSING
CYTOMECHANICAL PERTURBATIONS DURING LOW-INTENSITY ULTRASOUND PULSING
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DOI：
10.1016/j.ultrasmedbio.2014.01.003
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发表时间：
2014-07-01
影响因子：
2.9
通讯作者：
Yu, Alfred C. H.
中科院分区：
文献类型：
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作者：
Hu, Yaxin;Wan, Jennifer M. F.;Yu, Alfred C. H.
为了确定低强度超声的治疗潜力，重要的是表征其与活细胞的生物物理相互作用。在这里，通过一系列单细胞直接观察，我们表明，低强度的超声脉冲会引起细胞膜和细胞核水平的细胞力学扰动的动态过程。我们的研究是使用一个复合平台进行的，该平台将1 mhz超声暴露硬件耦合到共聚焦显微镜系统。在10分钟的时间内，将空峰时间平均强度为0.24 W/cm(2)（峰值正声压0.85 mpa）的短超声脉冲（5个周期，2 khz脉冲重复频率）传递给贴壁的神经母细胞瘤细胞，并在暴露前、暴露期间和暴露后对细胞动力学进行实时成像。亮场成像结果显示，低强度超声脉冲作用下细胞横截面积进行性缩小（25% ~ 45%,N = 7）；初始尺寸减小速率估计为每分钟8%-14%。这种收缩被发现是短暂的，因为超声细胞在暴露结束后30分钟内恢复到暴露前的大小（以每分钟0.4%-0.9%的速度增加）。三维共聚焦成像结果进一步显示：(i)超声诱导的膜收缩本质上是体积性的（减少21%-45%），（ii）核体积明显减少（减少12%-25%）。总之，这些发现表明，低强度超声脉冲，如果按分钟的顺序施加，将可逆地扰乱活细胞的物理和亚细胞结构。（E-mail: alfred.yu@hku.hk） (c) 2014年世界超声医学与生物学联合会。
To establish the therapeutic potential of low-intensity ultrasound, it is important to characterize its biophysical interactions with living cells. Here, through a series of single-cell direct observations, we show that low-intensity ultrasound pulsing would give rise to a dynamic course of cytomechanical perturbations at both the membrane and nucleus levels. Our investigation was conducted using a composite platform that coupled a 1-MHz ultrasound exposure hardware to a confocal microscopy system. Short ultrasound pulses (5 cycles, 2-kHz pulse repetition frequency) with a spatial-peak time-averaged intensity of 0.24 W/cm(2) (0.85-MPa peak positive acoustic pressure) were delivered over a 10-min period to adherent Neuro-2a neuroblastoma cells, and live imaging of cellular dynamics was performed before, during and after the exposure period. Bright-field imaging results revealed progressive shrinkage of cellular cross-sectional area (25%-45%, N = 7) during low-intensity ultrasound pulsing; the initial rate of size decrease was estimated to be 8%-14% per minute. This shrinkage was found to be transient, as the sonicated cells had recovered (at a rate of size increase of 0.4%-0.9% per minute) to their pre-exposure size within 30 min after the end of exposure. Three-dimensional confocal imaging results further revealed that (i) ultrasound-induced membrane contraction was volumetric in nature (21%-45% reduction), and (ii) a concomitant decrease in nucleus volume was evident (12%-25% reduction). Together, these findings indicate that low-intensity ultrasound pulsing, if applied on the order of minutes, would reversibly perturb the physical and subcellular structures of living cells. (E-mail: alfred.yu@hku.hk) (c) 2014 World Federation for Ultrasound in Medicine & Biology.