Cell mechanics using atomic force microscopy-based single-cell compression
Cell mechanics using atomic force microscopy-based single-cell compression
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DOI：
10.1021/la060561p
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发表时间：
2006-09-12
期刊：
影响因子：
3.9
通讯作者：
Liu, Gang-yu
中科院分区：
文献类型：
--
作者：
Lulevich, Valentin;Zink, Tiffany;Liu, Gang-yu
我们在此报告了基于原子力显微镜（AFM）中的力测量的单细胞压缩方法的建立。高分辨率明场或共焦激光扫描显微镜引导 AFM 探针的位置，然后监测细胞形状的变形，而微球修饰的 AFM 探针压缩细胞并测量力。活细胞的力和变形曲线揭示了小变形（< 30%）时的三次关系，30-70% 压缩时的多个峰值，以及超过 80% 变形时的快速增加。可以使用填充有不可压缩流体的不可渗透球囊的简单模型来定性和定量地描述初始压缩。应力峰值反映细胞膜破裂，随后细胞内成分变形和破裂，超过该值细胞反应变得不可逆。从球囊模型中提取活细胞膜的杨氏模量和弯曲常数，分别为10-30 MPa和17-52 kT。死亡细胞和固定细胞的初始压缩是使用赫兹接触理论建模的，假设细胞是均匀的球体。死细胞表现出 4-7.5 kPa 的细胞骨架弹性，而由于亚胺键的蛋白质交联，固定处理导致细胞骨架杨氏模量 (150-230 kPa) 急剧增加。这些结果证明了单细胞压缩方法对细胞分子水平结构变化的高敏感性，这为组织工程和癌症研究中的细胞力学研究提供了一个新的通用平台。
We report herein the establishment of a single-cell compression method based on force measurements in atomic force microscopy ( AFM). The high-resolution bright-field or confocal laser scanning microscopy guides the location of the AFM probe and then monitors the deformation of cell shape, while microsphere-modified AFM probes compress the cell and measure the force. Force and deformation profiles of living cells reveal a cubic relationship at small deformation (< 30%), multiple peaks at 30-70% compression, and a rapid increase at over 80% deformation. The initial compression may be described qualitatively and quantitatively using a simple model of a nonpermeable balloon filled with incompressible fluid. Stress peaks reflect cell membrane rupture, followed by the deformation and rupture of intracellular components, beyond which the cell responses become irreversible. The Young's modulus and bending constant of living cell membranes are extracted from the balloon models, with 10-30 MPa and 17-52 kT, respectively. The initial compression of dead and fixed cells is modeled using Hertzian contact theory, assuming that the cell is a homogeneous sphere. Dead cells exhibit a cytoskeleton elasticity of 4-7.5 kPa, while fixation treatment leads to a dramatic increase in the cytoskeletal Young's modulus (150-230 kPa) due to protein cross-linking by imine bonds. These results demonstrate the high sensitivity of the single-cell compression method to the molecular-level structural changes of cells, which suggests a new generic platform for investigating cell mechanics in tissue engineering and cancer research.