Viscoelastic properties of zonal articular chondrocytes measured by atomic force microscopy
Viscoelastic properties of zonal articular chondrocytes measured by atomic force microscopy
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DOI：
10.1016/j.joca.2005.12.003
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发表时间：
2006-06-01
影响因子：
7
通讯作者：
Guilak, F.
中科院分区：
文献类型：
--
作者：
Darling, E. M.;Zauscher, S.;Guilak, F.
目的：关节软骨细胞对化学和机械信号的反应取决于其起源区域相对于组织表面的距离。然而，人们对软骨细胞机械性能的区域变化知之甚少。本研究的目的是使用原子力显微镜 (AFM) 确定猪软骨细胞弹性和粘弹性特性的区域变化，并针对微量移液器抽吸验证该方法。方法：用坚硬的球形压头（直径 5 μm）压入的粘弹性、不可压缩、各向同性表面的应力松弛的理论解决方案 导出并适合从软骨浅层或中/深层分离的软骨细胞的 AFM 压痕的实验应力松弛数据。结果：软骨细胞的瞬时模量对于浅层细胞 (S) 为 0.55 +/- 0.23 kPa，对于中/深层细胞 (M/D) 为 0.29 +/- 0.14 kPa (P < 0.0001)，并且的 松弛模量为 0.31 +/- 0.15 kPa (S) 和 0.17 +/- 0.09 kPa (M/D) (P < 0.0001)。表观粘度为 1.15 +/- 0.66 kPa·s (S) 和 0.61 +/- 0.69 kPa-s (M/D) (P < 0.0001)。微移液器抽吸测试的结果显示相似的细胞模量但较高的表观粘度，表明这两种技术测量的机械特性相似。结论：我们的研究结果表明，软骨细胞的生物力学特性随起源区域的不同而显着不同，这与先前显示软骨细胞生物合成活性和基因表达的区域差异的研究一致。鉴于 AFM 的多功能性和动态测试能力，使用该技术进行应力松弛测量的能力可以进一步了解分离细胞的粘弹性特性。 (c) 2005 年国际骨关节炎研究协会。由爱思唯尔有限公司出版。保留所有权利。
Objective: Articular chondrocytes respond to chemical and mechanical signals depending on their zone of origin with respect to distance from the tissue surface. However, little is known of the zonal variations in cellular mechanical properties in cartilage. The goal of this study was to determine the zonal variations in the elastic and viscoelastic properties of porcine chondrocytes using atomic force microscopy (AFM), and to validate this method against micropipette aspiration.Methods: A theoretical solution for stress relaxation of a viscoelastic, incompressible, isotropic surface indented with a hard, spherical indenter (5 mu m diameter) was derived and fit to experimental stress-relaxation data for AFM indentation of chondrocytes isolated from the superficial or middle/deep zones of cartilage.Results: The instantaneous moduli of chondrocytes were 0.55 +/- 0.23 kPa for superficial cells (S) and 0.29 +/- 0.14 kPa for middle/deep cells (M/D) (P < 0.0001), and the relaxed moduli were 0.31 +/- 0.15 kPa (S) and 0.17 +/- 0.09 kPa (M/D) (P < 0.0001). The apparent viscosities were 1.15 +/- 0.66 kPa s (S) and 0.61 +/- 0.69 kPa-s (M/D) (P < 0.0001). Results from the micropipette aspiration test showed similar cell moduli but higher apparent viscosities, indicating that mechanical properties measured by these two techniques are similar.Conclusion: Our findings suggest that chondrocyte biomechanical properties differ significantly with the zone of origin, consistent with previous studies showing zonal differences in chondrocyte biosynthetic activity and gene expression. Given the versatility and dynamic testing capabilities of AFM, the ability to conduct stress-relaxation measurements using this technique may provide further insight into the viscoelastic properties of isolated cells. (c) 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.