Department of Mechanical and Industrial Engineering, University of Toronto , Toronto, Ontario, Canada M5S 3G8.
ACS Nano. 2014 Apr 22;8(4):3821-8. doi: 10.1021/nn500553z. Epub 2014 Apr 1.
The study of nuclear mechanical properties can provide insights into nuclear dynamics and its role in cellular mechanotransduction. While several methods have been developed to characterize nuclear mechanical properties, direct intracellular probing of the nucleus in situ is challenging. Here, a modified AFM (atomic force microscopy) needle penetration technique is demonstrated to mechanically characterize cell nuclei in situ. Cytoplasmic and nuclear stiffness were determined based on two different segments on the AFM indentation curves and were correlated with simultaneous confocal Z-stack microscopy reconstructions. On the basis of direct intracellular measurement, we show that the isolated nuclei from fibroblast-like cells exhibited significantly lower Young's moduli than intact nuclei in situ. We also show that there is in situ nucleus softening in the highly metastatic bladder cancer cell line T24 when compared to its less metastatic counterpart RT4. This technique has potential to become a reliable quantitative measurement tool for intracellular mechanics studies.
核力学性质的研究可以深入了解核动力学及其在细胞力学转导中的作用。虽然已经开发了几种方法来描述核力学性质，但直接在细胞内原位探测核仍然具有挑战性。本文展示了一种改进的原子力显微镜（AFM）针入技术，用于原位机械表征细胞核。基于 AFM 压痕曲线上的两个不同段来确定细胞质和核的硬度，并与同时进行的共聚焦 Z 堆叠显微镜重建相关联。基于直接的细胞内测量，我们表明，从成纤维样细胞中分离出的核的杨氏模量明显低于原位完整核。我们还表明，与转移性较低的 RT4 相比，高度转移性膀胱癌细胞系 T24 中的原位核软化。该技术有望成为细胞内力学研究的可靠定量测量工具。
