Physical characterization and dynamic pathophysiological study of endothel using scanning acoustic microscopy

目的：利用扫描声学显微镜（SAM）研究活体人内皮细胞和主动脉平滑肌细胞的声传播速度。方法和材料：分别用100 MHz、450 MHz和600 MHz超声对endothel进行C模和X-Z模成像。传播速度可以由450 MHz超声拍摄的C模式图像上条纹的位置和X-Z模式图像上的条纹位移由公式V_S=V_M+2f DELTAz计算得到（V_S：样品的传播声速，V_M：介质的传播声速，f：频率，DELTAz: X-Z模式图像上的条纹位移）。用SAM法测定生长组（G组）、差值组（D组）和低渗负荷组（H组）主动脉平滑肌细胞的传播声速。结果：以生理盐水为偶联液，在450 MHz频率下可检出细胞内颗粒，获得细胞内C模图像清晰。在450 MHz和600 MHz下观察到细胞内颗粒，但在100 MHz下未观察到。细胞的向上Z扫描图像有两个或三个黑白对比环。低渗负荷使观察到的对比环数量显著增加。D (1624) (]SY.+-。[)16m/sec]显著高于G (1571（]SY.+-）。[)14米/秒)和H （1585(]SY.+- .[)8米/秒）。SAM应该被认为是研究活细胞声学特性的有用方法。结论：即使在样品厚度未知的情况下，仅监测X-Z扫描过程中脉冲振幅的变化，也可以计算出传播声速。扫描图像显示与细胞表面曲率和衰减有关的特征。扫描声学显微镜应该被认为是研究活细胞声学特性的有效方法。

purpose : This study was executed to evaluate the acoustic propagation speed of live human endothel cell and aortic smooth muscle cell using scanning acoustic microscopy (SAM).method and material : We depicted the C mode and X-Z mode images of endothel with 100 MHz, 450 MHz and 600 MHz ultrasound. The propagation speed was able to be calculated from the location of the fringe on the C mode image and the fringe shift on the X-Z mode image taken with 450 MHz ultrasound from the formula V_S=V_M+2f DELTAz (V_S : propagation sound speed of the sample, V_M : propagation sound speed of the medium, f : frequency, DELTAz : fringe shift on X-Z mode image). The propagation sound speed of aortic smooth muscle cells in groups : growing (group G), differential (D) and on hypotonic loading (H), were evaluated with SAM.result : C mode image of endothel was obtained clearly with intracellular granules detectable at 450 MHz frequency using saline as the coupling fluid. Intracellular granules were observed at 450 MHz, and 600 MHz but not at 100 MHz. The upward Z scanning images of the cell had two or three black and white contrast rings. Hypotonic loading produced a significant increase in the number of contrast rings observed.The propagation speed of D (1624(]SY.+-。[)16m/sec) is significantly higher than that of G (1571(]SY.+-。[)14m/sec) and H (1585(]SY.+-。[)8m/sec). SAM should be considered a useful method for studying live cell acoustic properties.Conclusion : The propagation sound speed was calculated even when the sample thickness is unknown, monitoring only the pulse amplitude change during X-Z scanning. The scanned image exhibits features related to the cell surface curvature and attenuation. Scanning acoustic microscopy should be considered a useful method for studying live cell acoustic properties.