Sato M, Levesque M J, Nerem R M
J Biomech Eng. 1987 Feb;109(1):27-34. doi: 10.1115/1.3138638.
The mechanical properties of endothelial cells were measured using the micropipette technique. The cells employed were collected from bovine aortic endothelium and cultured in our laboratory. Endothelial cells from confluent monolayers under no-flow conditions were detached from their substrate by trypsin or by a mechanical method and suspended in modified Dulbecco medium (MDM). In the micropipette technique, a part of the cell is aspirated into the tip of the micropipette under a microscope, and the deformation measured from a photograph. In this study, the data obtained were analyzed using a model where the cytoskeletal elements, which are considered to be the primary stress bearing components, are assumed to reside in a submembranous, cortical layer. Detached cells were found to have almost homogeneous mechanical properties based on measurements from different regions of the surface of a single cell. However, a hysteresis loop was observed in the relation between pressure and cell deformation during the loading and unloading processes. The calculated elastic shear moduli obtained for the trypsin-detached cells were as much as 10-20 times larger than those of a red blood cell. Mechanically-detached cells had moduli approximately twice that of the trypsin detached cells. Passage time, i.e., cell culture age, had no influence on the mechanical properties of the trypsin-detached cells, but did have an effect on the mechanically-detached cells, with both the younger and older cells being somewhat stiffer.
采用微吸管技术测量内皮细胞的力学性能。所用细胞取自牛主动脉内皮，并在我们实验室进行培养。在无流动条件下，将汇合单层的内皮细胞通过胰蛋白酶或机械方法从其底物上分离下来，并悬浮于改良的杜尔贝科培养基（MDM）中。在微吸管技术中，在显微镜下将细胞的一部分吸入微吸管尖端，并从照片中测量变形情况。在本研究中，使用一个模型对获得的数据进行分析，该模型假定细胞骨架成分是主要的应力承受成分，位于细胞膜下的皮质层中。基于对单个细胞表面不同区域的测量发现，分离的细胞具有几乎均匀的力学性能。然而，在加载和卸载过程中，压力与细胞变形之间的关系中观察到滞后回线。计算得出，胰蛋白酶分离的细胞的弹性剪切模量比红细胞的弹性剪切模量大10至20倍。机械分离的细胞的模量约为胰蛋白酶分离细胞的两倍。传代时间，即细胞培养年龄，对胰蛋白酶分离的细胞的力学性能没有影响，但对机械分离的细胞有影响，较年轻和较老的细胞都稍硬一些。
