Mechanics of living cells measured by laser tracking microrheology
Mechanics of living cells measured by laser tracking microrheology
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DOI：
10.1016/s0006-3495(00)76725-7
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发表时间：
2000-04-01
影响因子：
3.4
通讯作者：
Kuo, SC
中科院分区：
文献类型：
--
作者：
Yamada, S;Wirtz, D;Kuo, SC
建立激光跟踪微观流变学（LTM）作为一种新的技术，用于量化细胞骨架力学，我们测量粘弹性模量与宽带宽（5十年）内的活细胞。随着粘弹性相位角的第一次亚细胞测量，LTM提供了不同频率下固体与液体行为的估计。在LTM中，粘弹性剪切模量是从嵌入在细胞骨架网络中的颗粒的布朗运动推断的。定制的激光光电子学可提供亚纳米和近微秒的粒子轨迹分辨率。肾脏上皮细胞系COS 7具有许多球形脂质储存颗粒，这些颗粒是非侵入性LTM的理想探针。虽然大多数颗粒是通过核周间隙，核周颗粒的一个子集是嵌入在致密的粘弹性细胞质。在所有的时间尺度上，嵌入的粒子表现出亚扩散行为，而不仅仅是由分子马达束缚。在低频下，层状区域（820 +/-：520达因/厘米2）比粘弹性核周区域（330 +/- 250达因/厘米2，p < 0.0001）更坚硬，但光谱在高频下会聚。虽然肌动蛋白破坏剂latrunculin A可以软化和软化lamebra，但生理水平的F-肌动蛋白（II +/- 1.2 dyne/cm（2））比lamebra柔软70倍。因此，F-肌动蛋白对于层状力学是必要的，但不是充分的。此外，在明显静止的细胞的延时中，单个板层颗粒可以显示出持续>10 a的模量的4倍变化。在广泛的频率范围内（0.1- 30，000 rad/s），LTM提供了一种独特的能力，可以无创地量化细胞粘弹性的动态局部变化。
To establish laser-tracking microrheology (LTM) as a new technique for quantifying cytoskeletal mechanics, we measure viscoelastic moduli with wide bandwidth (5 decades) within living cells. With the first subcellular measurements of viscoelastic phase angles, LTM provides estimates of solid versus liquid behavior at different frequencies. In LTM, the viscoelastic shear moduli are inferred from the Brownian motion of particles embedded in the cytoskeletal network. Custom laser optoelectronics provide sub-nanometer and near-microsecond resolution of particle trajectories. The kidney epithelial cell line, COS7, has numerous spherical lipid-storage granules that are ideal probes for noninvasive LTM. Although most granules are percolating through perinuclear spaces, a subset of perinuclear granules is embedded in dense viscoelastic cytoplasm. Over all time scales embedded particles exhibit subdiffusive behavior and are not merely tethered by molecular motors. At low frequencies, lamellar regions (820 +/-: 520 dyne/cm(2)) are more rigid than viscoelastic perinuclear regions (330 +/- 250 dyne/cm(2), p < 0.0001), but spectra converge at high frequencies. Although the actin-disrupting agent, latrunculin A, softens and liquefies lamellae, physiological levels of F-actin, alone (II +/- 1.2 dyne/cm(2)) are similar to 70-fold softer than lamellae. Therefore, F-actin is necessary for lamellae mechanics, but not sufficient. Furthermore, in time-lapse of apparently quiescent cells, individual lamellar granules can show similar to 4-fold changes in moduli that last >10 a. Over a broad range of frequencies (0.1-30,000 rad/s), LTM provides a unique ability to noninvasively quantify dynamic, local changes in cell viscoelasticity.