Butler J P, Kelly S M
Physiology Program, Harvard School of Public Health, Boston, MA 02115, USA.
Biorheology. 1998 May-Jun;35(3):193-209. doi: 10.1016/S0006-355X(99)80007-9.
Magnetic twisting cytometry is gaining wide applicability as a tool for the investigation of the rheological properties of cells and the mechanical properties of receptor-cytoskeletal interactions. Current technology involves the application and release of magnetically induced torques on small magnetic particles bound to or inside cells, with measurements of the resulting angular rotation of the particles. The properties of purely elastic or purely viscous materials can be determined by the angular strain and strain rate, respectively. However, the cytoskeleton and its linkage to cell surface receptors display elastic, viscous, and even plastic deformation, and the simultaneous characterization of these properties using only elastic or viscous models is internally inconsistent. Data interpretation is complicated by the fact that in current technology, the applied torques are not constant in time, but decrease as the particles rotate. This paper describes an internally consistent model consisting of a parallel viscoelastic element in series with a parallel viscoelastic element, and one approach to quantitative parameter evaluation. The unified model reproduces all essential features seen in data obtained from a wide variety of cell populations, and contains the pure elastic, viscoelastic, and viscous cases as subsets.
磁扭细胞术作为一种用于研究细胞流变特性和受体-细胞骨架相互作用力学特性的工具，正得到广泛应用。当前技术涉及对结合在细胞上或细胞内的小磁性颗粒施加和释放磁诱导扭矩，并测量颗粒由此产生的角旋转。纯弹性或纯粘性材料的特性可分别由角应变和应变率来确定。然而，细胞骨架及其与细胞表面受体的连接表现出弹性、粘性甚至塑性变形，仅使用弹性或粘性模型同时表征这些特性在内部是不一致的。在当前技术中，施加的扭矩并非随时间恒定，而是随着颗粒旋转而减小，这一事实使得数据解释变得复杂。本文描述了一个由一个并联粘弹性元件与另一个并联粘弹性元件串联组成的内部一致模型，以及一种定量参数评估方法。该统一模型再现了从各种细胞群体获得的数据中所看到的所有基本特征，并包含纯弹性、粘弹性和粘性情况作为子集。
