Fadhel Muhannad N, Berndl Elizabeth S L, Strohm Eric M, Kolios Michael C
Department of Physics, Ryerson University, Toronto, Ontario, Canada.
Department of Physics, Ryerson University, Toronto, Ontario, Canada.
Ultrasound Med Biol. 2015 Oct;41(10):2700-13. doi: 10.1016/j.ultrasmedbio.2015.06.003. Epub 2015 Jul 10.
Variations in the acoustic impedance throughout cells and tissue can be used to gain insight into cellular microstructures and the physiologic state of the cell. Ultrasound imaging can be used to create a map of the acoustic impedance, on which fluctuations can be used to help identify the dominant ultrasound scattering source in cells, providing information for ultrasound tissue characterization. The physiologic state of a cell can be inferred from the average acoustic impedance values, as many cellular physiologic changes are linked to an alteration in their mechanical properties. A recently proposed method, acoustic impedance imaging, has been used to measure the acoustic impedance maps of biological tissues, but the method has not been used to characterize individual cells. Using this method to image cells can result in more precise acoustic impedance maps of cells than obtained previously using time-resolved acoustic microscopy. We employed an acoustic microscope using a transducer with a center frequency of 375 MHz to calculate the acoustic impedance of normal (MCF-10 A) and cancerous (MCF-7) breast cells. The generated acoustic impedance maps and simulations suggest that the position of the nucleus with respect to the polystyrene substrate may have an effect on the measured acoustic impedance value of the cell. Fluorescence microscopy and confocal microscopy were used to correlate acoustic impedance images with the position of the nucleus within the cell. The average acoustic impedance statistically differed between normal and cancerous breast cells (1.636 ± 0.010 MRayl vs. 1.612 ± 0.006 MRayl), indicating that acoustic impedance could be used to differentiate between normal and cancerous cells.
整个细胞和组织中声阻抗的变化可用于深入了解细胞微观结构和细胞的生理状态。超声成像可用于创建声阻抗图，图上的波动可用于帮助识别细胞中主要的超声散射源，为超声组织表征提供信息。由于许多细胞生理变化与它们的机械性能改变有关，因此可以从平均声阻抗值推断细胞的生理状态。最近提出的一种方法——声阻抗成像，已被用于测量生物组织的声阻抗图，但该方法尚未用于表征单个细胞。使用这种方法对细胞成像可以得到比以前使用时间分辨声学显微镜获得的更精确的细胞声阻抗图。我们使用一个中心频率为375 MHz的换能器的声学显微镜来计算正常（MCF - 10 A）和癌性（MCF - 7）乳腺细胞的声阻抗。生成的声阻抗图和模拟结果表明，细胞核相对于聚苯乙烯底物的位置可能会对测得的细胞声阻抗值产生影响。使用荧光显微镜和共聚焦显微镜将声阻抗图像与细胞核在细胞内的位置相关联。正常和癌性乳腺细胞的平均声阻抗在统计学上存在差异（1.636±0.010兆瑞利与1.612±0.006兆瑞利），表明声阻抗可用于区分正常细胞和癌细胞。
